Congenital abnormalities in Pacific Island Countries and Territories: a scoping review

Abstract

Background

Pacific Island Countries and Territories experience disproportionately high rates of stillbirth, neonatal, and childhood deaths, yet the drivers of these outcomes remain unclear. The impact of congenital abnormalities within the Pacific has not been clearly established, despite these abnormalities being a leading global cause of infant and child mortality. This scoping review maps available literature to determine the current knowledge of congenital abnormalities in Pacific Island Countries and Territories.

Methods

Two independent reviewers searched six scholarly databases (PubMed, Scopus, CINHL, Proquest, Web of Science and Google Scholar) in addition to performing targeted web searches for grey literature. Searches were limited to sixteen Pacific Island Countries and Territories and extracted data was analysed as thematic summaries.

Results

Seventy-two sources were included in the final review. Papua New Guinea was the most represented Pacific nation in identified literature. Congenital abnormalities were commonly reported without description or specification to identify the type of abnormality, but congenital heart defects (n = 17) and neural tube defects (n = 13) were most often reported. The burden of congenital abnormalities between Pacific Island Countries and Territories was not comparable due to limited and varied data collection and reporting methods in the literature.

Conclusions

Our exploration of the body of knowledge on congenital abnormalities in Pacific Island Countries and Territories shows that there is an unequal representation of Pacific nations in literature focused on congenital abnormality research and reporting. This gap may reflect variations in the capacity for health research across different Pacific nations. The paucity of literature and generalised reporting of congenital abnormalities further demonstrates ongoing challenges to health surveillance pertaining to common causes of stillbirth, neonatal and childhood deaths in the region.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-026-27322-3.

Introduction

Congenital abnormalities (CA) are a major contributor to neonatal and childhood mortality and morbidity worldwide [1]. CA are defined as structural or functional abnormalities that develop during gestation [2], which are estimated to account for 11% of neonatal deaths and 4% of childhood deaths globally [3]. Survivors often experience lifelong disability, complex health challenges and reduced quality of life, with substantial implications for families, health systems and societies [3, 4].

The burden of mortality and morbidity attributed to CA is disproportionately borne by low- and middle-income countries (LMIC) [1, 5]. As deaths from infectious and preventable causes have declined, the relative contribution of non-communicable conditions such as CA to child mortality has increased [4]. In high-income countries (HIC) improvements in maternal care, early CA diagnosis, and neonatal health management have led to marked reductions in CA occurrences, severity and CA-related mortality [4]. In contrast, many LMIC have not experienced similar gains, raising concern that CA may contribute to persistently high levels of child mortality and morbidity in these settings [4].

Disparities in improvements in rates of neonatal mortality rates (NMR) are particularly evident in Pacific Island Countries and Territories (PICT). Despite international commitments to reduce NMR under the United Nations Sustainable Development Goal 3 [6], several PICT remain off track to meet the target of 12 neonatal deaths per 1,000 live births [3]. Indeed, over the past three decades, the Pacific region has experienced the slowest decline in NMR globally [3]. In neighbouring HIC (Australia and New Zealand), NMR rates average 2 per 1,000 live births compared to around 20 per 1,000 live births in PICT [3]. These persistently high rates suggest that key drivers of adverse pregnancy, neonatal and infant outcomes (APNIO) in PICT have not been fully addressed.

Within the Western Pacific region, CA are estimated to account for approximately 5% of childhood deaths [7]. However, this figure is likely an underestimation as many PICT are classified as LMIC, where access to diagnostic services, health surveillance systems and cause-of-death attribution is limited, and where socio-cultural beliefs may influence CA reporting and health-seeking behaviour [4, 5, 8]. As a result, the true burden of CA, and the contribution of CA to ongoing high NMR and child mortality and morbidity rates in PICT remains poorly understood.

Given the persistently high burden of NMR and child mortality and morbidity in PICT, and the potential for CA to be a substantial contributor to these outcomes, a clearer understanding of CA patterns and trends in this region is urgently needed. However, evidence pertaining to the prevalence, distribution, and characteristics of CA in PICT has, to date, not been comprehensively synthesised. This scoping review therefore aimed to identify and map the available literature on CA in PICT to describe current evidence, identify key knowledge gaps, and inform future research and health policy to reduce health inequities in the Western Pacific region.

Methodology

Study design and protocol

Given the limited a heterogenous nature of existing research in this field, a scoping review was conducted to identify and collate available literature and identify knowledge gaps on CA incidence and distribution within PICT. A scoping review was deemed appropriate to examine the range and nature of research activity within this field, draw conclusions about the overall context of research, and identify key gaps, rather than describe findings in detail. The review was informed by Arksey and O’Malley’s framework [9], comprised of the following five stages; (1) identifying the research question(s), (2) identifying relevant studies, (3) selection of relevant studies, (4) charting data and (5) collating, summarizing and reporting findings [9]. The scoping review was undertaken in accordance with the JBI methodology for scoping reviews [10], and follows reporting guidelines ascribed by PRISMA-extension for Scoping Reviews [11]. A detailed protocol is available online (https://osf.io/he3v2/).

Study inclusion

Literature included in our review were required to meet two inclusion criteria that (1) the source reported CA cases, including patient-level data and population estimates and (2) that the source pertained to one of the sixteen PICT of interest (American Samoa, Cook Islands, Federated States of Micronesia (FSM), Fiji, Kiribati, Nauru, Niue, Palau, Papua New Guinea (PNG), Republic of Marshall Islands (RMI), Samoa, Solomon Islands, Tokelau, Tonga, Tuvalu, Vanuatu). These nations are classified as Pacific Small Islands and Developing States (PSIDS) by the UN Department of Economic and Social Affairs [12], with the exception of American Samoa and Tokelau, which were included as they are geographically located within the region of interest and share cultural and socio-economic similarities with PSIDS.

Literature search

The search strategy was designed to capture a broad scope of relevant literature. Source-types eligible for review included journal articles, grey literature, books, theses, and conference papers. All study designs, including Demographic Health Surveys, other population-based surveys and case reports were included. Only sources published in English were eligible for inclusion. A preliminary search of PubMed and Google Scholar was conducted to identify relevant general search terms. Key search terms were then developed in consultation with research team members with expertise in reproductive physiology and cultural research within the Western Pacific. Broad search terms included “congenital abnormali*”, “congenital defects”, “perinatal deaths”, “congenital abnormality”, searched in combination with geographic terms “Pacific Islands”, “Polynesia”, “Melanesia”, “Micronesia”, and each relevant PICT. Terms referring to congenital heart defects and neural tube defects were included in the search strategy as these are the most prevalent CA globally [1]. Six scholarly databases (PubMed, Scopus, CINHL, Proquest, Web of Science, Google Scholar) were searched. Targeted searches of citations from reference lists were also used to identify relevant literature (backward citation searching). No date limit was set. Search strings comprised of a combination of key terms and Medical Subject Headings for both study concepts (Supplementary Table 1). Additionally, a targeted grey literature search for regional and national government reporting, was guided by the South Pacific Community (SPC) Statistics for Development Division ‘Census and Survey Calendar’ [13]. Initial database and grey literature searches were completed on the 16th of August 2023. The literature search process was repeated on 20th of August 2024 to capture any additional literature published over the preceding 12-month period.

Data analysis

Once all literature was retrieved, citations were collated for screening and analysis by two independent researchers using Covidence software (covidence.org). Literature was initially screened by title and abstract and any literature that did not meet inclusion criteria was removed (Fig. 1). During full-text screening, sources were excluded from the review if they did not meet the inclusion criteria, if no full-text was available, or if data from the text was already available from a primary source (in cases where sources were literature reviews). Data was extracted from the final pool of relevant literature by two independent researchers, using a Covidence data extraction tool. Extracted data was consolidated in Excel for thematic analysis and conflicts over inclusion were resolved during review by a third researcher.

Fig. 1.

PRISMA-ScR flow diagram of scoping review process

Results

Selection and characteristics of studies

The literature search returned 1,404 results captured via scholarly databases (n = 1,341), citation searches (n = 4), and grey literature (n = 59) (Fig. 1). Once duplicates were removed (n = 358), 1,046 sources were screened. A total of 72 sources were included in our final review published across the last 63 years (1966–2024) (Table 1). We report that the volume of available literature on CA in PICT has progressively increased in recent years. Four studies were published over the 1960s-1970s compared to 26 sources published within the last decade (2014–2024) (Fig. 2). Observational cohort studies were the most common source type (63%, n = 45) followed by case studies (11%, n = 8) and grey literature (8%, n = 6). The remaining 12 sources (16%) consisted of interventional studies [30, 39, 43], systematic and meta-analyses [4, 7, 50, 54, 57, 58, 81], one literature review [49], and a doctoral thesis [72].

Table 1.

Summary of literature. Overview of the 72 sources analysed in this review, including source characteristics, study aims, types of CA and potential determinants, and population statistics reported

Author(s)	Year	Source context	Type of publication	Study Aims	Type of CAs studied	CA determinants studied/discussed	CA statistics recorded
Gajdusek [14]	1977	Papua New Guinea (PNG)	Cross-sectional study	Describe socio-cultural perceptions and practices of a community in the Highlands of PNG toward individuals with congenital anomalies (CA) of genital organs	Genital organs	Suspected consanguinity	Prevalence of CA of genital organs in Simbari-Anga community 7 per 1,800 population
Korner [15]	1980	PNG	Retrospective cohort study	Analyse the types of cardiovascular disease in PNG in a representative sample of patients drawn from multiple centres	Congenital heart disease (CHD), Down Syndrome	Not applicable	Within the cohort of 251 individuals with cardiovascular disease, 8% of cases caused by congenital heart defects (CHD) (n = 20). CHD caused 3% of cardiac failures (2/75)
De Costa & Griew [16]	1982	PNG	Prospective cohort study	Determine the effects of chewing betel nut during pregnancy and puerperium on maternal and neonatal health outcomes	CDH, clubfoot, chromosomal, Respiratory, Urinary system	Substance use (Betel nut chewing)	No significant association between chewing betel nut during pregnancy and congenital anomalies
Herdt & Davidson [17]	1988	PNG	Retrospective cohort study	Provide a cross-cultural perspective on 5-alpha-reductase deficiency and the development of gender identity in males with genital organ CA	Genital organs	Consanguinity	14 cases of genital organ CA recorded amongst Sambia tribe in PNG reported from 1910–1983. Estimated incidence of 6 cases per 1,000 live births
Imperato-McGiniey et al. [18]	1991	PNG	Cohort study	Describe the biochemical profile of males genital organ CA and primary 5-alpha-reductase deficiency, and study the socio-cultural perceptions and practices surrounding these individuals in the community	Genital organs	Genetic	6 individuals with genital organ CA (aged 4 years-40 years) identified in the Simbari-Anga linguistic group in the Eastern Highlands of PNG
Klufio, Amoa & Kariwiga [19]	1994	PNG	Prospective cohort study	Provide socio-demographic and reproductive characteristics of parturient mothers at the PMGH	Non-specific abnormality	Not applicable	Within cohort of 676 total births, 15 stillbirths and 5 perinatal deaths recorded. 1 case of 'major congenital anomaly' recorded as cause of perinatal death
Jacob, Rosenfeld & Waiters [20]	1994	PNG	Retrospective cohort study	Describe the surgical repair and management of frontal encephaloceles in PNG	Encephaloceles, facial abnormalities	Not applicable	17 cases (aged < 5 years—18 + years) of congenital encephaloceles (1986–1993) across PMGH, Mt Hagan and Goroka Hospital
Dryden [21]	1997	PNG	Prospective cohort study	Record the prevalence of CAs recognizable after birth or soon after in a series of 10,000 babies delivered at PMGH	Clubfoot, cleft lip/palate, face, ears, microphthalmia, hydrocephalus, microcephalus, anencephalous, spina bifida, abdominal, CHD, genital, chromosomal, Respiratory	Environmental (mother's province of origin), Parity	Incidence of CA in cohort was 116 per 10,000 total births
Dewan et al. [22]	1998	PNG	Case study	Present case study of a patient presenting to PMGH with penile duplication	Penile duplication, anorectal duplication	Not applicable	Not applicable
Amoa et al. [23]	1998	PNG	Case control study	Determine the causes of stillbirths, and the incidence of avoidable factors at PMGH	Non-specific abnormality	Not applicable	CAs significantly associated with stillbirths, caused 6% (n = 19) of stillbirths within cohort of 315 stillbirths in PMGH (1995–1997)
McMaster et al. [24]	1999	PNG	Case study	Report on the first identified case of hyperekplexia in PNG	Nervous system (Hyperekplexia)	Genetic mutation	Not applicable
Watters et al. [25]	2001	PNG	Review of publications and surgical audit data	Describe the surgical pathology and surgeorn capacity in 2000	Cleft lip/palate, Non-specific abnormality	Not applicable	CAs caused 5% (n = 14) of deaths in surgical ward of PMGH (1996–1998)
Tefuarani et al. [26]	2001	PNG	Retrospective cohort study	Critically analyse the programme for surgical management of children in PNG with CHD	CHD	Not applicable	Estimated annual number of new cases of CHD in PNG between 800—1,000. Study cohort (n = 165 children with CHD) included ventricular septal defect (34%), tetralogy of Fallot (23%) and patent ductus arteriosus (16.4%)
Amoa, Sapuri & Klufio [27]	2001	PNG	Case control study	Determine risk factors of breech presentation in PMGH and evaluate if modifications of clinical practice may improve perinatal outcomes	Non-specific abnormality	Not applicable	CAs significantly associated with persistent breech presentations. Incidence of CAs was 21 cases per 1,004 breech infants (1988–1993)
Duke et al. [28]	2002	PNG	Prospective cohort study	Collect accurate data on disease and microbial-specific causes and avoidable factors in child deaths at Goroka Hospital	CHD, Down Syndrome, cleft lip/palate, diaphragmatic hernia; hydrocephaly, anencephaly, urinary system, digestive tract	Not applicable	CAs caused 12.5% (n = 44) of child deaths in Goroka Hospital. CHD caused 7.1% (n = 25) of deaths
Tefuarani et al. [29]	2002	PNG	Retrospective cohort study	Describe the selection, preoperative clinical features, and post-operative outcomes of children with CHD managed by the Royal Alexandra Hospital for Children PNG cardiac surgical programme	CHD	Not applicable	230 children identified with CHD from PNG selected for the Royal Alexandra Hospital for Children cardiac surgical programme in Australia
Lehmann et al. [30]	2002	PNG	Case control study	Determine the efficacy and safety of pneumococcal polysaccharide vaccine delivered to women at 28–38 weeks’ gestation	CHD	Not applicable	One reported infant death from CHD in maternal immunization group. No significant difference of CA incidence between control and vaccinated group during 3-year follow-up period
Amoa, Klufio, & Amos [31]	2002	PNG	Case control study	Identify socio-demographic, obstetric and intrapartum factors associated with early neonatal death at PMGH	CHD, neural tube defects (NTD), chromosomal, diaphragmatic hernia, non-specific abnormality	Maternal substance use (betel nut chewing, smoking)	CAs caused 17% (n = 26) of deaths in early neonatal period amongst study cohort (300 total births)
Tefuarani et al. [32]	2004	PNG	Retrospective cohort study	Report the medium-to-long-term outcome in children selected to undergo cardiac surgery at the Royal Alexandra Hospital for Children in Sydney, Australia between 1978 and 1994	CHD	Not applicable	Outcomes of cohort of 125 children with CHD who survived (short-term) post-cardiac surgery was compared cohort of 31 children with CHD who were excluded from surgery. Survival probability of different types of CHD within the cohorts compared
Tay, Kitz & Booth [33]	2004	PNG	Case study	Present a case of Goldenhar syndrome in a child from PNG	Goldenhar Syndrome (eyes, face, ear, renal)	Not applicable	Not applicable
Duke et al. [34]	2005	PNG	Prospective cohort study	Investigate the epidemiology of illness among young infants at remote health clinics and determine risk factors for mortality to be used as triggers for emergency treatment or referral	Non-specific abnormality	Not applicable	2 CAs recorded amongst cohort (n = 511) of infants (< 2 months) presenting to rural and remote health facilities between Dec 1 2001-Jan 31 2002
Kaptigau, Ke & Rosenfeld [35]	2007	PNG	Prospective cohort study	Prospectively audit and follow up hydrocephalus cases in Port More over 2 years from January 2003 to December 2004 and ascertain the causes and the outcome of treatment	Hydrocephalus	Maternal nutrition (folate intake)	2003–2004: 34 cases of congenital hydrocephalus presentations to PMGH (56% of all hydrocephalus presentations)
Kaptigau, Mamadi & Kevau [36]	2007	PNG	Retrospective cohort study	To detail the management of different spinal diseases presentations to PMGH between 2004 and 2006	Spina bifida	Not applicable	2004–2006: 5 cases of spina bifida admissions recorded. 2003–2004, 1 case of myelomeningocele in > 20,000 live births in Labour Ward
Culverwell & Tapping [37]	2009	PNG	Retrospective cohort study	To explore the burden of congenital talipes equinovarus in the East Sepik region of PNG	Talipes equinovarus (clubfoot)	Maternal nutrition (anaemia secondary to malaria); environmental (seasonal link)	2001–2003: Incidence of clubfoot presenting to hospital 2.7 per 1,000 live births per year
Gende [38]	2012	PNG	Retrospective cohort study	Describe a technique for severe bilateral cleft lip repair without presurgical orthodontics or lip adhesion and short-term outcomes of cases with this procedure	Cleft lip/palate	Not applicable	Incidence of cleft lip/palate in PNG: 1 per 640 live births (or 1.6 per 1,000)
Pharoah, Buttfield, Hetzel [39]	2012	PNG	Randomised control trial (RCT)	Determine if intramuscular iodised oil is effective in the prevention of endemic cretinism and that	Congenital Hypothyroidism	Maternal nutrition (iodine deficiency)	Congenital hypothyroidism in case group (mothers receive iodised oil): 7 cases (1.4%) per 498 children. Control group (mothers do not receive iodised oil): 26 cases (4.9%) per 534 children
Ome et al. [40]	2013	PNG	Case study	Report a case of prune belly syndrome from PNG	Prune Belly Syndrome (Respiratory, genital, urinary, musculoskeletal)	Genetic mutation	Not applicable
Karl et al. [41]	2015	PNG	Prospective cohort study	Compare the performance of established alternative estimators of gestational age (GA) with foetal biometry in the first half of pregnancy to assess if combination of various measures in mathematical models could improve GA estimation	Non-specific abnormality	Not applicable	Of the 2,793 women enrolled in study, 0.8% (n = 6) delivered infants with CAs
Ome-Kaius et al. [42]	2015	PNG	Prospective cohort study	Assess the impact of betel nut chewing on adverse birth outcomes in a cohort of pregnant women in rural lowland PNG	Non-specific abnormality	Maternal Substance use (betel nut chewing, smoking, alcohol)	No significant association between maternal use of betel nut and CAs. Proportion of infants born with CAs to mothers who were 'heavy users' of chewing betel nut was 1.1%, compared to 1.4% of babies born with CAs to non-users
Morris et al. [43]	2017	PNG	Prospective dose escalation study	Investigate the safety and effectiveness of a regimen of oral misoprostol in women undergoing induction of labour	Non-specific abnormality	Not applicable	Within cohort of 209 births, 2 babies born with CAs
Korowi et al. [44]	2019	PNG	Retrospective cohort study	Identify causes of neonatal admissions and deaths in the Eastern Highlands Provincial Hospital Special Care Nursery, identify interventions to improve neonatal outcomes	Non-specific abnormality	Not applicable	CAs caused 5.5% (n = 28) of neonatal deaths in Special Care Nursery (2011–2015). Reported CAs case-fatality rate of 35% on the ward
Vallely et al. [45]	2020	PNG	Retrospective cohort study	Undertake a retrospective perinatal death audit and assessment of avoidable factors associated with stillbirths	Non-specific abnormality	Not applicable	July 2017- Jan 2020: 59 stillbirths recorded per 2558 total births in 2 provinces (stillbirth rate 23 per 1000 births). CAs caused 5% (n = 3) of stillbirths
Vallely et al. [46]	2021	PNG	Retrospective cohort study	Determine causes of early neonatal death and associated avoidable factors among women participating in a cluster-randomised crossover trial in PNG	Diaphragmatic hernia, microcephaly, anophthalmia	Not applicable	CAs caused of 11.4% (n = 4) of neonatal deaths (n = 35) amongst cohort (n = 2,499 live births). Included deaths from Microcephaly/anophthalmia (n = 3) and diaphragmatic hernia (n = 1)
Yakea et al. [47]	2022	PNG	Case study	Describe the management of gastroschisis in a low-birthweight baby	Gastroschisis	Not applicable	Not applicable
Toti et al. [48]	2024	PNG	Prospective cohort study	Report the types, incidence, and geographic distribution of birth defects in the East New Britain Province of PNG	CHD, NTD, nervous system, craniofacial, chromosomal/genetic syndrome, gastrointestinal, abdominal, respiratory, musculoskeletal, renal, genitourinary, multisystem CA	Environmental (mother's province of origin, environmental exposures)	Incidence of CA per 2,000 live births at Rabaul Hospital (2018–2020): 37 CHD (27%), 19 nervous system (13.9%), 19 craniofacial (13.9%), 26 chromosomal and genetic syndromes (19%), 14 gastrointestinal/abdominal (10.2%), 12 respiratory/thoracic (8.7%), 6 MSK (4.4%), 4 renal/genitourinary (2.9%), 7 multi-system (5.1%)
Stevenson et al. [49]	1966	Fiji	Literature Review	Determine and compare frequencies of anencephalous, hydrocephalus, spina bifida and other NTD amongst different countries	Anencephaly	Environmental determinants	Frequency of anencephalous in Colonial War Memorial Hospital (Fiji) (1956–1959): Indigenous Fijians = 1 case/2,791 births (0.33 per 1,000). Fijian Indians = 6 cases/4,494. births (1.33 per 1,000)
Cutts & Vynnycky [50]	1999	Fiji	Systematic analysis	Model annual rates of rubella infection, to estimate the number of cases of congenital rubella syndrome (CRS) occurring in developing countries	CRS	Infectious disease (Rubella)	Incidence of CRS in Fiji (1973) 251 per 100,000 live births average [95% CI, 204–302]
Lonnée, Chetty & Rawailiu [51]	2007	Fiji	Case study	Report the surgical repair of an abdominal defect and perioperative management of the first pair of live conjoined twins delivered in Fiji	Musculoskeletal, digestive tract, circulatory, genital, respiratory, Thoracopagus	Not applicable	Not applicable
Cama, Nagra & Chang [52]	2011	Fiji	Case study	Present a case report of a female newborn with a rare congenital abdominal wall defect associated with intestinal malformation	Short-gut Syndrome (abdominal wall/intestinal malformation, digestive)	Not applicable	Not applicable
Singh et al. [53]	2013	Fiji	Retrospective cohort study	Report incidence of CRS in Fiji and incidence of notified cases of rubella since 1995, and document CRS classification between 1995–2010	CRS, Eyes, Ears, Circulatory, Nervous; Non-specific abnormality	Infectious disease (Rubella)	Incidence of CRS in Fiji (1995–2010) ranged from 0.4 cases per 1,000 live births (1994) to 1.7 cases per 1,000 (2010). CRS accounted for 30% (n = 294) of all CAs (n = 977) amongst infants born 1995–2010
Arth et al. [54]	2016	Fiji	Systematic analysis	Examine the global status in 2015 of prevention of folic acid-preventable spina bifida and anencephaly	Anencephaly, Spina Bifida	Maternal nutrition (folate intake)	NTD prevalence in Fiji pre-fortification: 1.5 per 1,000 live births. Nationally, 18 NTD prevented annually due to fortification
Thean et al. [55]	2021	Fiji	Case study	Describe the case of an infant (11 months) with Down Syndrome, Malnutrition, and Hyperkeratotic Skin Lesions at a referral hospital in Fiji	Down Syndrome	Not applicable	Not applicable
Brody et al. [56]	1970	Pohnpei, Federated States of Micronesia (FSM)	Cross-sectional study	Study the burden of congenital blindness and potential genetic and environmental determinants amongst Pingelapese people	Eyes (Congenital blindness)	Genetic, suspected consanguinity	Incidence of congenital blindness in Mand Village cohort: 22 cases per 285 population. Estimate 4–10% of Pingelapese people are blind from birth
Yomai & Pavlin [57]	2010	Chuuk (FSM)	Retrospective cohort study	Explore genetic and environmental causes associated with microphthalmia and anophthalmia in Chuuk State	Microphthalmia, anophthalmia	Genetic, maternal nutrition (Vit A deficiency)	Incidence of microphthalmia and anophthalmia in Chuuk: 140 cases per 100,000
Baud et al. [58]	2017	Yap (FSM)	Systematic literature review	Provide updates in the knowledge of Zika virus and associated CAs as of early 2017	Microcephaly	Infectious disease (Zika)	No associated nervous system malformation cases confirmed from the 49 confirmed Zika cases on Yap (2016)
Albakri et al. [59]	2023	Chuuk (FSM)	Prospective observational case series	To determine the cause of Leber congenital amaurosis (LCA) in Chuuk state (FSM)	Leber congenital amaurosis	Genetic, suspected consanguinity	LCA identified in 5 individuals from population of 3,910 on Tonoas Island (1.28 per 1,000 population)
Clouse & Damon [60]	1971	Solomon Islands	Cross-sectional study	Document the health of communities with limited exposure to industrialization, surveying the health of lungs, heart, spleen, scoliosis, bone age and dental development	Wolff-Parkinson-White syndrome, atrial septal defect	Not applicable	1 case of Wolff-Parkinson-White syndrome diagnosed from 438 Lau community members studied
Durski et al. [61]	2016	Solomon Islands	Retrospective cohort study	Describe CRS outbreak investigation in Solomon Islands (2012–2013), findings and measures implemented	CRS (congenital cataracts, CHD)	Infectious disease (Rubella)	January—March 2013, 13 infants born with CRS, 3 known deaths (23% fatality rate). Of total CRS cases (n = 13), infants had congenital cataracts (n = 6), and combined congenital cataracts and CHD (n = 3)
Jones et al. [62]	2018	Solomon Islands	Retrospective cohort study	Calculate the perinatal mortality rate in Kirakira Hospital over a 3-year period (2014–2016)	Non-specific abnormality	Not applicable	CAs made up 8% of neonatal mortality in Kirakira Hospital (2014–2016)
Sandakabatu et al. [63]	2018	Solomon Islands	Prospective cohort study	Identify areas in the death audit process in the paediatric department of the National Hospital in Honiara for improvement	Non-specific abnormality, CHD, Tracheo-oesophageal fistula	Not applicable	CAs were direct or underlying cause of 9% (n = 6) of neonatal and child deaths (n = 66) amongst admissions between 1 st Jan-30th June 2017
Tosif et al. [64]	2018	Solomon Islands	Cross-sectional study	Identify strengths and obstacles for improving the quality of newborn care in Solomon Islands	Non-specific abnormality	Not applicable	CAs caused 9% of neonatal deaths in Solomon Islands Referral Hospital (2014)
Tosif et al. [65]	2019	Solomon Islands	Retrospective cohort study	Describe the perinatal mortality and clinical factors associated with poor newborn outcomes at four hospitals in Solomon Islands	CHD, spina bifida, hydrocephalus, anencephaly, digestive tract, Non-specific abnormality	Not applicable	Incidence of CAs (total) in National Referral Hospital special care nursery (2014–2016): 96 cases per 2,550 admissions. CAs caused 8.4% (n = 17) of deaths
De Silva et al. [66]	2022	Solomon Islands	Retrospective cohort study	Investigate the incidence of stillbirth and associated risk factors in the Solomon Islands	Hydrocephalus, trisomy 21, Non-specific abnormality	Not applicable	CAs caused 4.7% (n = 8) of antepartum and 14.3% (n = 4) of intrapartum deaths at National referral hospital (2017–2018)
Finau & Taylor [67]	1988	Tonga	Retrospective cohort study	Report on screening for cardiac murmurs and disease among schoolchildren on the island of Eua (1985), and profile of rheumatic heart disease amongst the population	CHD	Not applicable	Crude prevalence of CHD amongst Eua population was 0.15%. 6 CHD cases identified amongst total population n = 4,017
Carter et al. [68]	2012	Tonga	Retrospective cohort study	Review quality of locally collected cause of death data from medical certification and present a national death profile based on amended data	Non-specific abnormality	Not applicable	6 deaths from CAs reported (0-4yrs) in Tonga, 10% of deaths for children under 4yrs (2008)
Tonga National Statistics Department [69]	2018	Tonga	Grey literature	Assess the degree of activity limitations, participation restrictions and societal activities for persons with disability	Non-specific abnormality	Not applicable	Prevalence of CAs amongst People Living with Disability in Tonga was 68 per 1,000 people with disability (2018)
Conard [70]	1992	Republic of Marshall Islands, (RMI)	Retrospective cohort study	Report the experiences of a medical team providing care for Marshallese population exposed to fallout radiation	Non-specific abnormality	Radiation exposure	CAs identified in 8.4% (n = 8) of unexposed cohort, and 9.7% (n = 23) of exposed cohort. No significant association reported
World Health Organization [71]	2016	RMI	Grey literature	Provide a situational report on the global status of Zika virus, Microcephaly and Guillain–Barre Syndrome as of October 2016	Microcephaly, central nervous system	Infectious disease (Zika)	1 case of microcephaly/central nervous system abnormality in an infant, suggestive of congenital Zika infection
Barker [72]	1985	Niue	PhD dissertation	Examine cultural values, child-rearing practices, family and household organization, and use of formal and informal health services for children	Chromosomal, cleft palate, bilateral talipes (clubfoot), hydrocele	Not applicable	CA cases (n = 5) identified from Child Welfare records in June 1982, including chromosomal (n = 1), cleft palate (n = 1), bilateral talipes (n = 1) and hydroceles (n = 2)
Siosikefu & Haberkorn [73]	2008	Niue	Grey literature	Present demographic, social and economic characteristics of Niue and provide a measure of development	Non-specific abnormality	Not applicable	1997–2001: One case of severe CA reported as cause of infant death. CA incidence of 3.5 per 1,000 total births
Cook Islands Ministry of Health [74]	2020	Cook Islands	Grey literature	Provide a summary of the health status of people living in the Cook Islands	Non-specific abnormality, Chromosomal abnormality	Not applicable	2016: 2 deaths from CAs (17.4 per 100,000 population). 2017: 1 death from CA (8.7 per 100,000 population). No deaths from CA recorded in 2015, 2018–2020
Palau Ministry of Health [75]	2015	Palau	Grey literature	Collate and present reports on the Bureau of Hospital and Clinical Services, Bureau of Nursing, Bureau of Public Health and Administrative Services	Non-specific abnormality	Not applicable	CAs caused 0.8% (n = 13) of all deaths (all ages) between 2003–2012
Sicree et al. [76]	1986	Fiji, Niue, Cook Islands, Nauru	Cross-sectional	Assess the association between parity and diabetes prevalence, and between diabetes prevalence and stillbirth occurrence	Non-specific abnormality	Maternal nutrition (glucose tolerance, gestational diabetes)	CAs identified in < 0.7% of pregnancies within study cohort
Meza-Valencia et al. [77]	2005	RMI, American Samoa, FSM	Retrospective cohort study	Establish the incidence of Hirschsprung Disease in children from the United States Associated Pacific Islands (USAPIs) and compare to incidence in developed countries	Hirschsprung disease	Genetic, Consanguinity	Average annual incidence of Hirschsprung disease 1994–2002 in FSM: 1 per 3,190 per total births. In RMI: 1 per 5,577 total births; in American Samoa 1 per 7,304 total births
Van Konkelenberg, Galea and Bhushan [78]	2007	Western Pacific	Grey literature	Explore the links between poverty and NCDs in the Western Pacific Region	Non-specific abnormality	Not applicable	CAs caused an estimated 108,000 deaths in the Western Pacific region in 2003
Batts, Thompson & Person [79]	2009	RMI, American Samoa, FSM	Retrospective cohort study	Compare the frequency of congenital diaphragmatic hernia (CDH) presentation in USAPIs to high-income countries	Diaphragmatic hernia, digestive (malrotation), microphthalmia	Not applicable	Total cases of CDH identified (1997–2006): in Federated States of Micronesia (n = 8), RMI (n = 3) and American Samoa (n = 1)
Black et al. [7]	2010	Fiji; Solomon Islands, RMI, Tonga, Palau, FSM, Niue, Cook Islands, Samoa, Kiribati, Tuvalu, Nauru, Vanuatu	Systematic analysis	Report new global, regional, and national estimates for 2008 of the major causes of death in children younger than 5 years	Non-specific abnormality	Not applicable	CAs cause an estimated 5% of deaths under 5 years old within the WHO Western Pacific region
Shapiro-Mendoza et al. [80]	2017	RMI, American Samoa, FSM	Retrospective cohort study	Report pregnancy outcomes after maternal Zika virus infection during pregnancy in US Territories between January 2016-April 2017	Microcephaly, Eyes	Infectious disease (Zika)	Amongst pregnancies reported with possible Zika infection (n = 2,549), 5% (n = 122) infants born with CAs, including microcephaly (n = 108). Data aggregated for USAPIs
Kancherla et al. [81]	2018	Fiji, Solomon Islands, Kiribati	Systematic analysis	Estimate the proportion of folic acid-preventable spina bifida and anencephaly (FAP SBA) from mandatory fortification of wheat and/or maize flour with FA during 2017	Spina bifida, anencephaly	Maternal nutrition (folate intake)	Prevalence of NTD per 1,000 live births pre-fortification in Fiji (n = 2); Kiribati (n = = 1.7); and Solomon Islands (n = 1.5). Estimated annual total FAP SBA cases prevented in Fiji (n = 27), Kiribati (n = 0), Solomon Islands (n = 8)
Rice et al. [82]	2018	RMI, American Samoa, FSM	Retrospective cohort study	Identify Zika-associated CAs and neurodevelopmental abnormalities associated with congenital Zika virus infection amongst USAPIs and assess reported follow-up care	Central nervous system, microcephaly, eyes	Infectious disease (Zika)	Amongst cohort of infants from Zika virus infected pregnancies receiving follow-up care (n = 1,450), 14% (n = 203) had Zika-associated CAs
Lu [83]	2023	Niue, Tokelau, Cook Islands	Retrospective data review	Quantitively define the global, regional, and national epidemiological trends in NTD incidence, mortality and disability-adjusted lift years	NTD	Maternal nutrition (folate intake)	Cook Islands: Age-standardised incidence of NTD 0.03 per 100,000 births; Age-standardised mortality from NTD 0.03 per 100,000 (between 1990–2019). Niue & Tokelau recorded < 1 case NTD, < 1 NTD mortality, < 1 DALY from NTD (per 100,000 births age-standardised incidence rate)
Perin et al. [4]	2023	PNG, Solomon Islands, Fiji, RMI, Tonga, Palau, FSM, Niue, Cook Islands, Samoa, Kiribati, Tuvalu, Nauru, Vanuatu	Systematic analysis	Examine the potential for bias in the estimate of under-5 mortality due to birth defects recently produced by the WHO and the Maternal and Child Epidemiology Estimation research group	Non-specific abnormality	Not applicable	Estimated rate of under-5 deaths caused by CAs (per 1,000 live births) in PICT: PNG (n = 2.7); Solomon Islands (n = 2.8); Fiji (n = 5); RMI = (n = 4.4), Tonga (n = 3.7), Palau (n = 4.7), FSM (n = 3.9), Niue (n = 0), Cook Islands = (n = 4), Samoa (n = 2.3), Kiribati (n = 5.2), Tuvalu (n = 3.2), Nauru (n = 3.3), Vanuatu (n = 3.8)

Fig. 2.

Volume of literature published per decade. The total number of captured literature published per decade

Pacific Islands disproportionately represented in published literature

Across all PICT (Fig. 3A) sources derived from PNG dominated the available research and resources relating to CA (50% of literature) (Fig. 3B). Data was also captured from Fiji = 15%; FSM and Solomon Islands 14%; other islands and territories < 10%; with Tokelau and Western Pacific at only 1%.

Fig. 3.

A Map of Pacific Island Countries and Territories included in the review. B Volume of literature published by Pacific Island Country or Territory. The total number of sources that report congenital abnormality (CA) data (individual case studies/population statistics) for each PICT. One study reported CA data for the Western Pacific region, aggregating data from PICT with other Oceania nations. Below each country is the corresponding population estimate from The Pacific Community (SPC) [84]

Disproportionate identification of congenital abnormality types in PICT

Congenital abnormalities were commonly reported (37% of sources) without adequate clinical descriptions. Amongst the body of literature that did specify CA type, congenital heart defects (CHD) (n = 17) were the most reported, followed by neural tube defects (NTD) (n = 13), including anencephaly, spina bifida and encephalocele (Table 2). PNG reported the most diverse range of CA (Fig. 4) which included NTD [20, 21, 28, 31, 35, 36, 48], CHD [15, 21, 26, 28–30, 32, 48], cleft palate [21, 25, 28, 38, 48], chromosomal abnormalities [15, 16, 21, 28, 31, 48], clubfoot [16, 21, 37, 48], and other musculoskeletal abnormalities [16, 21, 28, 31, 37, 40, 46–48]. While many countries reported on more than one type of CA, several smaller island nations (Tuvalu, Vanuatu, Nauru, Palau, Samoa) did not report any specific CA type (Fig. 4). Countries which reported a variety of CA were also those most represented in the literature. Due to the paucity of information available for all PICT, it was not possible to determine how the distribution of CA may vary across PICT.

Table 2.

Types of congenital abnormalities (CA) reported in the captured literature. CA reported in the literature and number of sources that reported the specifical abnormality/grouping. ‘Non-specific’ refers to the number of sources reporting CA without identifying the specific abnormality/condition

Type of CA	Number of studies
Non-specific abnormality	27
Congenital heart defects	16
Neural tube defects	13
Eyes	12
Musculoskeletal	11
Central nervous system defects	8
Genital organs	8
Down Syndrome	6
Cleft lip/palate	6
Digestive tract	6
Face/ear/neck	6
Respiratory system	5
Clubfoot	4
Chromosomal	4
Urinary/renal system	4
Congenital rubella syndrome	3
Endocrine system	1

Fig. 4.

Distribution of reported congenital abnormalities (CA) per country. The distribution of different types of CA reported per country/region are displayed. The X axis is the percentage of studies (per country) that reported a CA type/group. Each colour corresponds to a specific CA type/group. Grey (‘Non-specified defects’) represents the percentage of studies (per country) that reported cases under the general term ‘congenital abnormalities’ without specifying the type/group of CA. Note: Abbreviations used for congenital rubella syndrome (CRS), and the Federated States of Micronesia (FSM)

Determinants of congenital abnormalities reported in literature

We next analysed the reported determinants of CA in PICT research. Potential risk factors for CA were identified in less than half (40%) of the literature. Genetic risk factors were reported and linked to potential consanguinity (intra-familial union) within the population [14, 17, 56, 59, 77]. Two sources investigated congenital blindness and Leber Amaurosis in FSM, determining a greater incidence of these rare conditions amongst the atoll communities likely due to reproduction occurring within small genetic pools [56, 59]. Suspected consanguinity was also reported as a potential determinant of a cluster of cases of genital malformation identified in remote populations located in the PNG Highlands [14, 17].

Communicable diseases such as Zika virus and Rubella were highlighted as causal agents for specific CA in the Pacific. Zika virus outbreaks in US-affiliated Territories (FSM, RMI and American Samoa) in 2016–2017 prompted several investigations demonstrating the rise of microcephaly or central nervous system (CNS) abnormalities associated with gestational infection [58, 80, 82]. Rubella infection during pregnancy was also a concern in this region, with vertical transmission causing congenital rubella syndrome (CRS) and subsequent abnormalities of the eyes, ears, heart and nervous system [50, 53]. A systematic analysis of reported rubella and CRS cases in LMIC included modelling for CRS infection and associated CA in Fiji [50]. The burden of rubella-associated CA in Fiji was further explored through a review of hospital records from 1995–2010, reporting the incidence of CA, including CRS, presenting at health facilities during this period [53]. Following a spike in Rubella cases in Solomon Islands in 2012, an outbreak investigation report identified the subsequent CRS cases and infants born with various CA nationally [61].

Finally, maternal nutrition and exposure to substances were considered potential risk factors for CA across the PICT region [35, 37, 39, 42, 54, 57, 76, 81]. In PNG, the effect of chewing betel nut during pregnancy on CA incidence was investigated, however, no significant association was identified [42]. In 1980–1982, a retrospective cohort study in four PICT (Fiji, Niue, Cook Islands, and Nauru) investigated the association of gestational diabetes mellitus (GDM) with parity and stillbirth [76]. The self-reported incidence of CA amongst the cohort (< 0.7% of pregnancies amongst each population) was smaller than hypothesised (6%), and was thus insufficient to conduct analysis of association with GDM [76]. Maternal deficiency in vitamin A, iodine and anaemia (secondary to malaria infection) were discussed risk factors for CA within the captured literature [37, 39, 57]. Few papers (n = 4) discussed the association of folate deficiency in the development of NTD. These sources included an audit of hydrocephalus cases in a PNG referral hospital [35], two systematic analyses detailing the status of folic acid (FA) preventable spina bifida and anencephaly globally [54, 81], and a review of NTD incidence reported to the Global Burden of Disease database (1990–2019) [83].

Discussion

This scoping review highlights the limited literature on CA in PICT. Of the CA which were reported, congenital heart defects (CHD) were the most frequent, likely reflecting the higher prevalence of these CA rather than any limitation of the search strategy. Globally, CHD are the most common abnormality, with an estimated birth prevalence of 9.41 cases per 1,000 live births [85]. In contrast, studies from PICT show substantial variation in CHD prevalence, often differing markedly from global averages. For example, in 1985, school screenings and hospital record reviews on Eua Island (Tonga) identified CHD cases in approximately 0.15% of the Island’s population (1.5 cases per 1,000 people) [67]. Meanwhile, two prospective cohort studies from PNG reported considerably different rates. At Port Moresby General Hospital in 1985, 9 cases of CHD were identified among 10,000 consecutive births (0.9 cases per 1,000 live births) [21]. More recently, a study at Rabaul Hospital (PNG—East New Britain) reported 37 cases amongst the first 2,000 live births (18.5 cases per 1,000 live births), greatly exceeding the global average [48]. These discrepancies between historical [21, 67] and recent [48] CHD rates in the Pacific likely reflect advancements in clinical and diagnostic capacity over the last 20 years [85].

Following CHD, neural tube defects (NTD) were the second most reported CA in PICT. Common NTD (anencephaly, encephalocele, spina bifida) are typically associated with severe external structural deformities of the skull and spine [86], and an estimated global incidence of 20 cases per 10,000 births [86]. Prospective cohort studies in two PNG hospitals revealed high rates of NTD [21, 48]. At Port Moresby Hospital, 23 cases were identified among 10,000 total births [21], and NTD accounted for the highest proportion of stillbirths, with 47.8% of affected babies stillborn [21]. At Rabaul Hospital, 10 cases were identified among 2,000 live births (50 cases per 10,000 live births), greatly exceeding both global estimates and rates observed at other hospitals within the same country [48]. In contrast, other PICT nations (Cook Islands, Niue, and Tokelau) appear to have a relatively low burden of NTD, with the Global Burden of Disease Database reporting fewer than one new case per country in 2017 [83]. However, as these data rely primarily on population censuses and demographic health surveys [87], they may underestimate NTD incidence due to limited diagnostic and surveillance capacities, common to some PICT [4, 5].

Adequate maternal nutrition is critical for healthy foetal development and for reducing the risk of adverse pregnancy outcomes, including CA [2]. Deficits in key micronutrients such as iodine and folate are known to contribute to specific CA, including congenital hypothyroidism and NTD [2, 81]. However, few of the identified studies investigated links between maternal nutrition and CA in the Pacific context. In our review, one study examined the impact of iodised oil intake during pregnancy on congenital hypothyroidism in a PNG cohort [39]. Three additional studies evaluated folic acid (FA) supplementation and NTD prevalence globally as part of systematic reviews which included PICT, but did not focus specifically on the nuanced Pacific context [54, 81, 83]. The most recent global update on FA-preventable spina bifida and anencephaly modelled pre-fortification NTD estimates for Fiji, Kiribati and Solomon Islands, at 20, 17 and 15 cases per 10,000 live births respectively [81]. In comparison, neighbouring HIC (Australia and New Zealand) reported lower pre-fortification rates of 13.3 and 11.2 cases per 10,000 births respectively, further supporting the hypothesis that low- and middle-income Pacific nations bear an inequitable burden of NTD [88]. Given the high risk of mortality and sever morbidity associated with nutrition-related CA, this inequity reinforces the critical need for targeted maternal nutrition research, policy, and interventions in PICT.

This review identified an unequal distribution of published CA literature across Pacific Island nations. PNG studies dominated research, while interestingly, high-income PICT such as Tokelau, Nauru, Niue, and American Samoa were largely absent. This pattern suggests that domestic infrastructure and research capacity, rather than national income status likely determines research outputs. For example, 50% of sources were from PNG, recognised as a LMIC, whilst only one source was identified from Tokelau (a territory of New Zealand) which is considered a HIC [89]. PNG has a population of approximately 10.6 million [90], compared to around 2,500 in Tokelau [91], and possesses several well-established health research-capable institutions including the Institute of Medical Research (IMR), University of PNG (UPNG) and Port Moresby General Hospital (PMGH), which were major contributors to the literature on CA. More specifically, of the 13 studies published exclusively by PICT authors, 10 (77%) were affiliated with at least one of the three PNG research institutions [16, 19, 21, 23, 24, 31, 36, 38, 42, 43]. However, we found that presence of domestic infrastructure for health research did not always equate to output. Although Fiji, the Solomon Islands, and FSM also have research institutes and universities, fewer than 30% of literature from these nations involved in-country organisations. These findings indicate that while domestic infrastructure is important for health research, outputs are also influenced by a multitude of factors likely to include population size and international collaboration.

Collaborative research was a prominent feature of the literature on CA in PICT. Almost half (48%) of studies involved partnerships between in-country stakeholders and international researchers or funding organisations, often reflecting historical regional affiliations and current socio-economic spheres of influence. For example, Australia is PNG’s largest development partner [92], and more than half (58%) of research from PNG was conducted in collaboration with Australian research institutes, universities, and funding organisations [15, 20, 22, 25, 26, 29, 30, 32–35, 39–42, 45–47]. Similarily, literature from US-Affiliated Pacific Islands (RMI, FSM, Palau, and American Samoa) was commonly supported by American research institutes and funding bodies [4, 7, 56–59, 70, 77, 79, 80, 82].

Although collaborative research can enhance local capacity, it is important to note that a third of studies (33%) lacked in-country stakeholder involvement. Engaging local stakeholders is critical to ensure research is contextually relevant, scientifically robust and translatable into local health system improvements [93]. Co-design approaches also facilitate knowledge transfer, resource sharing, and the development of sustainable research implementation and infrastructure [93, 94]. While some argue that collaborations between HIC and LMIC may be susceptible to structural power imbalances within research teams, and may perpetuate inequities between countries [95–97], the evidence presented here shows that collaboration effectively increases research outputs and can strengthen research capabilities in low-resource settings [94]. Our review highlights the benefits of partnerships between Pacific nations and HIC and suggests that expanding regional collaborations could further research capacity in key areas such as CA prevalence and prevention through improved monitoring and surveillance, and the development of targeted health policies and interventions.

Strengthening monitoring and surveillance systems in the Pacific is essential to address the burden of CA, neonatal and child mortality, in line with the UN SDG 3 [98]. Robust surveillance infrastructure is necessary to capture accurate and reliable population-level data on CA, allowing trends to be monitored, cluster detected, and baseline burden assessed. This information can guide health policy and help evaluate progress toward national and global health targets. At the individual-level, surveillance programmes can also facilitate timely referrals and access to treatment [99].

Limited or uneven reporting of CA across PICT may contribute to delays in developing public health programs for prevention, diagnosis, and treatment. In addition, a lack of evidence may reinforce the perception of CA as a lesser health priority among policymakers, further slowing program development and progress towards the UN SDGs. To combat this, international endorsement can help to elevate CA as important health indicators. For example, in 2024 the 77th World Health Assembly passed Resolution (WHA77.5) calling for accelerated progress toward SDG 3.1 and 3.2 through comprehensive newborn screening, including examinations at birth for visible abnormalities, as well as tests for hearing, vision, and CHD, in addition to blood tests [100]. Such screening, alongside improving CA diagnosis and management [100, 101], can provide local policymakers with robust evidence to understand the true burden of CA and prioritize interventions to reduce neonatal and child mortality.

Given resource constraints in many PICT, initial screening efforts should prioritize one or more CA based on their contribution to local child mortality and morbidity, local diagnostic and management capacity, and the potential impact of early detection on quality of life. Accordingly, the WHO is developing a framework to support LMIC in integrating CA screening, treatment and management into health systems [100], and the Pacific Community (SPC) and WHO jointly established The Pacific Public Health Surveillance Network (PPHSN) in 1996 to facilitate cooperation between member states in monitoring population health [102]. While the PPHSN primarily focuses on infectious disease and emergency response [102], its networks could be leveraged to advance CA surveillance in the region.

Regionally, national registries in Australia and New Zealand provide established models for CA monitoring [103, 104]. Given their experience and existing research collaborations in the Western Pacific, these HIC are well positioned to support the development of CA surveillance infrastructure in PICT. Strengthening such systems would enable accurate tracking of CA, guide targeted prevention strategies, and ultimately reduce preventable neonatal and child mortality in the region.

Limitations of the available literature

The literature captured in this scoping review often grouped all abnormalities under the umbrella term ‘congenital abnormalities’, limiting insight into the distribution of specific conditions nationally and across the Pacific. This likely reflects technical and logistic barriers to diagnosis and health surveillance in the region, including the gradual transition to electronic health information systems, limited centralised reporting and constrained human resources [8, 105]. Such challenges may contribute to incomplete reporting on CA in the captured literature [8, 106].

Comparisons between regional or global CA statistics were further complicated by differences in reporting indicators. Some studies reported CA incidence per live births [4, 26, 35, 37, 38, 48, 50, 52–54, 57, 81], others per total births [21, 39, 49], or by total population [61, 67, 74, 79, 83]. As a result, many population-level statistics were not directly comparable. Additionally, this scoping review did not exclude studies based on quality, as capturing the full range of available literature was necessary to map the landscape of CA reporting in PICT. Assessing study quality and potential risk of bias was considered important to contextualise findings, although the variability in reporting standards, study design and denominators across studies limits comparability. The review was also restricted to literature published in English, with search strategies excluding non-English texts at point-of-capture, which may have excluded relevant studies or reports published in other languages. These limitations highlight both the challenges in generating robust CA data in PICT and the ongoing need to strengthen research and surveillance systems in the region to accurately capture the burden of CA.

Conclusion

The distribution and focus of CA research in PICT reflect systematic differences in health research capacity, surveillance infrastructure and policy prioritization. The predominance of studies on CHS and NTD appears to reflect their prevalence and relative detectability rather than a comprehensive characterization of the burden of these CA in the Pacific. Limited and uneven reporting across PICT suggests that substantial CA burdens may remain under-documented, potentially influenced by evolving changes in dietary patterns, food insecurity, and compounded by constrained diagnostic and health system capacity. Addressing knowledge gaps in this field requires the coordinated development of surveillance systems, targeted newborn screening programs and research capacity through collaborative, co-designed initiatives with regional and international partners. Generating context-specific evidence will enable informed policymaking, effective resource allocation, and the implantation of preventative and clinical interventions to ultimately support progress towards UN SDGs and reduce the burden of CA and resulting neonatal and child mortality rates in the Western Pacific.

Abbreviations

LMIC

Low- and middle-income countries

HIC

High-income countries

NMR

Neonatal mortality rate

PICT

Pacific Island Countries and Territories

APNIO

Adverse pregnancy, neonatal, and infant outcomes

WHO

World Health Organization

CAs

Congenital abnormalities

PRISMA

Preferred Reporting Items for Systematic reviews and Meta-Analyses

FSM

Federated States of Micronesia

PNG

Papua New Guinea

RMI

Republic of Marshall Islands

PSIDS

Pacific Small Island Developing States

SPC

The South Pacific Community

PMGH

Port Moresby General Hospital

CHD

Congenital heart defect

NTD

Neural tube defect

GA

Gestational age

CRS

Congenital rubella syndrome

LCA

Leber congenital amaurosis

FAP SBA

Folic acid-preventable spina bifida and anencephaly

GDM

Gestational diabetes mellitus

FA

Folic acid

IMR

Institute of Medical Research

UPNG

University of Papua New Guinea

PPHSN

The Pacific Public Health Surveillance Network

Authors’ contributions

GK and EK developed the manuscript concept. EK and JM screened articles and GK acted as a moderator for screening. EK and GK, drafted the manuscript text with input from RT and BD. EK and GK prepared figures and tables. All authors reviewed the manuscript.

Funding

Research Training Program scholarship (Australian Government) awarded to EK.

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.