Abstract
Background: Preterm delivery represents an important public health problem due to its neonatal outcomes. There are numerous complications that occur due to prematurity, but the most significant one is represented by neonatal death. Even if the certain mechanism of prematurity is elusive, there are various risk factors known to be involved in the etiology of preterm birth, among which one is young age.
Objectives: The present study aims to find whether preterm delivery has a higher rate in adolescent patients and if neonatal outcomes are different in adolescent and adult patients.
Patients and methods:We performed an observational retrospective study about preterm infants from adolescent and adult patients. Thus, we analyzed 96 patients aged between 13 and 38 years who delivered in our unit between October 1st 2018 and December 31st 2021. Patients were divided into two groups: a study group (n=59), which included adolescents who delivered preterm, and a control group (n=37), which comprised adult patients who delivered preterm. We evaluated the rate of prematurity of all births and among patients enrolled in the present study and the neonatal outcome by newborn’s weight, one-minute newborn’s Apgar score and Neonatal Intensive Care Unit (NICU) admission.
Results:In our study, the rate of prematurity was higher in adolescent patients, with a rate of 61.46%. The newborns’ outcomes, analyzed by newborn’s weight and one-minute Apgar score, were better in adolescent patients compared to adult ones. Therefore, newborns from adult patients needed neonatal intensive care more often, with a rate of 62.16%, while in the study group the percentage was 38.98%. The rate of antenatal care was higher in adult patients compared to adolescent ones (32.43% versus 27.12%).
Conclusion:Adolescents have a higher risk of preterm delivery; however, their newborns have better outcomes than those of adult patients. The lack of antenatal care represents a risk factor for preterm delivery.
Keywords:preterm delivery, adolescent pregnancy, newborn’s weight, one-minute Apgar score, Neonatal Intensive Care Unit.
INTRODUCTION
Preterm delivery, defined as childbirth before 37 completed weeks of gestation, is the main cause of perinatal morbidity and mortality worldwide (1-4). The consequences of preterm delivery are represented by short- and long-term adverse outcomes (1-7). Complications may occur in the early newborn period (e.g., respiratory distress syndrome or necrotizing enterocolitis) but also in the long-term (e.g., bronchopulmonary dysplasia or retinopathy of prematurity) (8). Preterm infants who experience one or more of the above-mentioned complications have a high risk of neurological disabilities (8). More than that, all over the world, prematurity accounts for approximately 35% of all neonatal deaths (9, 10).
The incidence of preterm birth varies depending on the demographic characteristics. In Europe, Australia, Northern America, Asia and Africa, the rate of preterm deliveries ranges between 5% and 13% (1, 4, 11-14). Worldwide, prematurity is estimated to affect 11% of all live births. Given the high incidence of preterm delivery and its related complications, it is a significant public health problem (9).
There are various risk factors for preterm delivery, including history of preterm birth, inadequate prenatal care, anemia, substance abuse, premature rupture of membranes, vaginal infections, gestational hypertension, maternal age less than 20 years or over 35 years, multiple pregnancies, and ethic characteristics or genetic attributes (1, 13-33). Despite the involvement of multiple risk factors, the etiology of preterm delivery has not been completed established yet (20, 26, 28). Because the underlying causes of preterm delivery may be due to biochemical mechanisms of labor interacting with multiplicity of medical and socio-economic factors, it is difficult to predict and prevent it (1).
As previously mentioned, one of those risk factors is represented by maternal age. Adolescent pregnancies are associated with a high risk of adverse neonatal complications, including preterm delivery. It is assumed that teenagers have a higher risk of pregnancy complications due to the biological immaturity; however, researches have recently shown that maternal and fetal complications were more likely to be associated to lack of antenatal care, poverty and low socio-economic status (34-37).
The purpose of the present study is to compare the rate of preterm delivery among adolescent and adult patients and to analyze the neonatal outcomes of preterm newborns from these two groups. Also, we explored whether, despite preterm birth complications, maternal age may influence the neonatal outcome.
PATIENTS AND METHODS
We performed an observational retrospective study with the aim of evaluating the neonatal outcomes of preterm newborns from adolescent and adult patients who delivered in the Department of Obstetrics and Gynecology of Bucharest University Emergency Hospital. The study was carried out between October 1st 2018 – December 31st 2021 and included 96 patients. Subjects were divided into two groups: a study group, which comprised, 59 adolescent patients aged 13–19 years, and a control group that consisted of 37 adult patients aged 20–38 years.
Maternal age was recorded at the time of admission to hospital. Gestational age was recorded according to the last menstrual period, if known, or ultrasound report. Deliveries were recorded as expulsion of the fetus after 24 completed weeks of gestation or over 500 grams. Gestational products below 24 weeks of gestation or below 500 grams were considered abortions and were not included in the present study.
Preterm birth was defined as delivery before 37 completed weeks of gestation. The information regarding pregnancy and neonatal outcomes data were retrieved from the hospitalization sheets and the Base Data System of Bucharest University Emergency Hospital.
Inclusion criteria were represented by patients aged between 13 and 38 years who delivered preterm in our unit and provided an informed consent for participation in the present study which has been signed by either each of them or the legal tutor for patients aged under 16.
Exclusion criteria included refusal to participate in the study, presence of associated pathologies such as infection with hepatitis C virus, hepatitis B virus or immunodeficiency virus, and patients with multiple pregnancies.
Figure 1 illustrates the selection and distribution of patients participating in the study
RESULTS
We explored 96 patients aged between 13 and 38 years who delivered preterm in our unit during the study period and observed that 4.51% of all births were registered among adolescents. Prematurity accounted for 0.99% of all births, with adolescent preterm deliveries representing 0.61%. The rate of prematurity was higher for teenage patients compared to adult ones (13.53% versus 0.40%) (Figure 2).
The cases were stratified by maternal age, area of residence BMI category, gestational age, status of antenatal care, birth weight, one-minute Apgar score and NICU admission (Table 1).
The rate of preterm births in our study was 61.46% among adolescents and 38.54% among adult patients (Figure 3).
We evaluated the neonatal status by the newborn’s weight, one-minute Apgar score, and NICU admission. Newborns’ weights were higher in the study group compared to the control group (Figure 4). Most of the patients in both groups delivered a newborn whose birth weight varied between 2,000 and 2,999 grams.
Most of the newborns from both the study and control groups had a one-minute Apgar score of 8 (Figure 5). On the other hand, there were two early neonatal deaths in the study group. It is of note that eight newborns in the study group, but group had a one-minute Apgar score of 8, while the second most common Apgar score was 5.
Regrading NICU admission, intensive care was needed by most of the adult patients’ preterm newborns and by none of those born to adolescent patients (Figure 6).
DISCUSSION
Preterm births affect approximately 13 million infants, but its incidence depends on demographic characteristics (3). Thus, the rate varies between 12% and 13% in the US and between 5% and 9% in Europe (4, 38, 39). It is known that young age represents a risk factor for preterm delivery and therefore, adolescents have a higher risk of preterm birth (34). A study on 1080 adolescents and 19807 adult subjects showed that the rate of preterm birth was 10.2% in adolescent patients and 8.9% in patients aged 20–34 years (36). A systemic review and meta-analysis regarding the neonatal outcomes from adolescents who were living in Canada has also found out that patients in this age group had a higher risk of preterm delivery than adult ones (34). Our study revealed that, among all births, a higher rate of young patients delivered preterm compared to adult ones. As well, the majority of patients enrolled in the present study were adolescents (61.46%). A possible explanation for the high rates of prematurity among adolescents may be the higher incidence of lack of antenatal care in adolescent patients (72.88%) compared to adult ones (67.57%).
Regarding the neonatal outcomes, we evaluated the newborns’ weight, one-minute Apgar score and need for NICU. It is clear that prematurity affects the newborns’ weight and Apgar score, but it significant to find whether there is any difference between these in adolescents’ newborns compared to adult patients’ ones. We showed that preterm newborns from teenagers had better outcomes than those from adult patients. Therefore, the mean weight was 2.243 grams in the study group versus 1.930 grams in the control group. The mean one-minute Apgar score was 7.16 in newborns to adolescents and 6.75 in those to adult patients. Regarding the neonatal intensive care, admission to NICU was required for most of the newborns to adult patients but for only 38.98% of those to patients included in the study group. These outcomes may be mainly due to the high incidence of no prenatal care in the study group, which explains why most adolescent patients did not know their last menstrual period. As well, studies show that adolescents have a higher risk of low weight birth compared to adults (34). Therefore, the gestational age evaluated by ultrasound exam may be misled among adolescent patients who had not undergone any prenatal visit and did not know their last menstrual period. This is also an acceptable explication for the low rate of NICU admissions for the newborns to patients in the study group.
Limitation of the study
The present study has some limitations that should be taken into account for further research. The sample size is small, therefore large-scale studies should be performed in order to report more accurate results. More than that, the lack of prenatal care in both groups, especially in adolescent patients, may influences the outcomes, hence more patients with adequate prenatal care and the risk of preterm delivery should be evaluated. Moreover, the socio-economic status, an important parameter known to influence the neonatal outcomes mainly in adolescent patients (34), was not available in the database.
CONCLUSION
Preterm delivery is an important public health problem due to its both short- and long-term complications. The most significant and easy action that healthcare providers can take to prevent preterm birth is to implement new strategies to encourage prenatal care, particularly among teenage patients. Adolescent pregnancy involves a high risk of preterm delivery due to biological immaturity and, to a greater extent, due to lack of antenatal care.
Conflict of interests: none declared.
Financial support: none declared.
Author contributions: All authors contributed equally in developing this article. All authors have read and agreed to the published version of the manuscript.
Institutional Review Board Statement: The study was approved by the local Ethical Committee of University Emergency Hospital Bucharest.
Informed consent: Informed consent was obtained from all patients involved in the study.
Data availability: The datasets used and analyzed during the current study are available from the corresponding author on reasonable request.
FIGURE 1.
Selection and distribution of patients participating in the study
FIGURE 2.
The rate of preterm birth in adolescent and adult patients in relation to all births
TABLE 1.
Description of study participants and their characteristics
FIGURE 3.
The rate of patients who delivered preterm in the study and control groups
FIGURE 4.
Newborns’ distribution according to their weight in the study and control groups
FIGURE 5.
Newborns’ distribution by their one-minute Apgar score in the study and control groups
FIGURE 6.
The rate of NICU admission of preterm newborns from the study and control groups
Contributor Information
Ana Veronica UZUNOV, Doctoral School of “Carol Davila” University of Medicine and Pharmacy, Bucharest, Romania.
Diana Cristina SECARA, “Carol Davila” University of Medicine and Pharmacy, Bucharest, Romania; Department of Obstetrics and Gynaecology, University Emergency Hospital Bucharest, Bucharest, Romania.
Andreea Elena CONSTANTIN, Department of Obstetrics and Gynaecology, University Emergency Hospital Bucharest, Bucharest, Romania.
Claudia MEHEDINTU, “Carol Davila” University of Medicine and Pharmacy, Bucharest, Romania; Department of Obstetrics and Gynaecology, Filantropia Clinical Hospital of Obstetrics and Gynaecology, Bucharest, Romania.
Monica Mihaela CIRSTOIU, “Carol Davila” University of Medicine and Pharmacy, Bucharest, Romania; Department of Obstetrics and Gynaecology, University Emergency Hospital Bucharest, Bucharest, Romania.
References
- 1.Jiang M, Mishu MM, Lu D, Yin X. A case control study of risk factors and neonatal outcomes of preterm birth. Taiwan J Obstet Gynecol. 2018;57:814–818. doi: 10.1016/j.tjog.2018.10.008. [DOI] [PubMed] [Google Scholar]
- 2.Zhonghua F, Chan K, Za Z. Diagnosis and therapy guideline of preterm birth. Chinese J Obstet Gynecol. 2014;49:481–485. [PubMed] [Google Scholar]
- 3.Simmons LE, Rubens CE, Darmstadt GL, Gravett MG. Preventing preterm birth and neonatal mortality: exploring the epidemiology, causes, and interventions. Semin Perinatol. 2010;34:408–415. doi: 10.1053/j.semperi.2010.09.005. [DOI] [PubMed] [Google Scholar]
- 4.Goldenberg RL, Culhane JF, Iams JD, Romero R. Epidemiology and causes of preterm birth. The Lancet. 2008;371:75–84. doi: 10.1016/S0140-6736(08)60074-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Petrou S, Eddama O, Mangham L. A structured review of the recent literature on the economic consequences of preterm birth. Arch Dis Child Fetal Neonatal Ed. 2011;96:F225–F232. doi: 10.1136/adc.2009.161117. [DOI] [PubMed] [Google Scholar]
- 6.Saigal S, Doyle LW. An overview of mortality and sequelae of preterm birth from infancy to adulthood. The Lancet. 2008;371:261–269. doi: 10.1016/S0140-6736(08)60136-1. [DOI] [PubMed] [Google Scholar]
- 7.Petrou S, Sach T, Davidson L. The long‐term costs of preterm birth and low birth weight: Results of a systematic review. Child Care Health Dev. 2001;27:97–115. doi: 10.1046/j.1365-2214.2001.00203.x. [DOI] [PubMed] [Google Scholar]
- 8.Randis TM. Complications associated with premature birth. AMA Journal of Ethics. 2008;10:647–650. doi: 10.1001/virtualmentor.2008.10.10.cprl1-0810. [DOI] [PubMed] [Google Scholar]
- 9.Williams TC, Drake AJ. Preterm birth in evolutionary context: a predictive adaptive response? Philosophical Transactions of the Royal Society B. 2019;374:20180121. doi: 10.1098/rstb.2018.0121. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Blencowe H, Cousens S, Chou D, et al. Born too soon: the global epidemiology of 15 million preterm births. Reproductive Health. 2013;10:1–14. doi: 10.1186/1742-4755-10-S1-S2. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Wen SW, Smith G, Yang Q, Walker M. Epidemiology of preterm birth and neonatal outcome. Semin Fet Neonatal Med. 2004;9:429–435. doi: 10.1016/j.siny.2004.04.002. [DOI] [PubMed] [Google Scholar]
- 13.Beck S, Wojdyla D, Say L, et al. The worldwide incidence of preterm birth: a systematic review of maternal mortality and morbidity. Bull World Health Organ. 2010;88:31–38. doi: 10.2471/BLT.08.062554. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Martin JA, Kung HC, Mathews TJ, et al. Annual summary of vital statistics: 2006. Pediatrics. 2008;121:788–801. doi: 10.1542/peds.2007-3753. [DOI] [PubMed] [Google Scholar]
- 16.Lumley J. Defining the problem: the epidemiology of preterm birth. BJOG. 2003;110:3–7. [PubMed] [Google Scholar]
- 17.Murphy DJ. Epidemiology and environmental factors in preterm labour. Best Pract Res Clin Obstet Gynaecol. 2007;21:773–789. doi: 10.1016/j.bpobgyn.2007.03.001. [DOI] [PubMed] [Google Scholar]
- 18.Burguet A, Kaminski M, Abraham‐Lerat L, et al. The complex relationship between smoking in pregnancy and very preterm delivery: results of the Epipage study. BJOG. 2004;111:258–265. doi: 10.1046/j.1471-0528.2003.00037.x. [DOI] [PubMed] [Google Scholar]
- 19.Svensson AC, Sandin S, Cnattingius S, et al. Maternal effects for preterm birth: a genetic epidemiologic study of 630,000 families. Am J Epidemiol. 2009;170:1365–1372. doi: 10.1093/aje/kwp328. [DOI] [PubMed] [Google Scholar]
- 20.Ahumada-Barrios ME, Alvarado GF. Risk Factors for premature birth in a hospital. Rev Lat Am Enfermagem. 2016;24:e2750. doi: 10.1590/1518-8345.0775.2750. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21.Schwab FD, Zettler EK, Moh A, et al. Predictive factors for preterm delivery under rural conditions in post-tsunami Banda Aceh. Journal of Perinatal Medicine. 2016;44:511–515. doi: 10.1515/jpm-2015-0004. [DOI] [PubMed] [Google Scholar]
- 22.Morgan-Ortiz F, Cinco-Sánchez A, Douriet-Marín FA, et al. Factores sociodemográficos y obstétricos asociados con nacimiento pretérmino. Ginecología y Obstetricia de México. 2010;78:103–109. [PubMed] [Google Scholar]
- 23.Covarrubias LO, Aguirre GER, Chapuz JR, et al. Factores maternos relacionados con prematuridad. Ginecología y Obstetricia de México. 2008;76:526–536. [PubMed] [Google Scholar]
- 24.Genes Barrios VB. Factores de riesgo asociados al parto pretérmino. Rev Nac 2012.
- 25.Scholl TO, Hediger ML, Fischer RL, Shearer JW. Anemia vs iron deficiency: increased risk of preterm delivery in a prospective study. Am J Clin Nutr. 1992;55:985–988. doi: 10.1093/ajcn/55.5.985. [DOI] [PubMed] [Google Scholar]
- 26.Giacomin-Carmiol L, Leal-Mateos M, Moya-Sibaja RÁ. Anemia materna en el tercer trimestre de embarazo como factor de riesgo para parto pretérmino. Acta Médica Costarricense. 2009;51:39–43. [Google Scholar]
- 27.Morisaki N, Togoobaatar G, Vogel JP, et al. Risk factors for spontaneous and provider‐initiated preterm delivery in high and low Human Development Index countries: a secondary analysis of the World Health Organization Multicountry Survey on Maternal and Newborn Health. BJOG. 2014;121:101–109. doi: 10.1111/1471-0528.12631. [DOI] [PubMed] [Google Scholar]
- 28.Rodríguez-Coutiño SI, Ramos-González R, Hernández-Herrera RJ. Factores de riesgo para la prematurez. Estudio de casos y controles. Ginecología y obstetricia de México. 2013;81:499–503. [PubMed] [Google Scholar]
- 29.Ouattara A, Ouedraogo CM, Ouedraogo A, Lankoande J. Factors associated with preterm birth in an urban African environment: A case-control study at the University Teaching Hospital of Ouagadougou and Saint Camille Medical Center. Médecine et Santé Tropicales. 2015;25:296–299. doi: 10.1684/mst.2015.0465. [DOI] [PubMed] [Google Scholar]
- 30.Pérez-Molina J, Panduro-Barón G, Quezada-López C. Factores maternos asociados con nacimiento pretérmino espontáneo versus pretérmino nacido por cesárea. Ginecologia y Obstetricia de Mexico. 2011;79:607–612. [Google Scholar]
- 31.Peña-Martí G, Barbato J, Betancourt C, et al. Aet alón entre prematuridad y embarazadas en edad avanzada. Revista de Obstetricia y Ginecología de Venezuela. 2007;67:15–22. [Google Scholar]
- 32.Rodríguez-Fernández A, Ruíz-De la Fuente M, Sanhueza-Riquelme X, et al. Association between Maternal Factors, Preterm Birth, and Low Birth Weight of Chilean Singletons. Children. 2022;9:967. doi: 10.3390/children9070967. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 33.Frey HA, Klebanoff MA. The epidemiology, etiology, and costs of preterm birth. Sem Fetal Neonat Med. 2016;21:68–73. doi: 10.1016/j.siny.2015.12.011. [DOI] [PubMed] [Google Scholar]
- 34.DeMarco N, Twynstra J, Ospina MB, et al. Prevalence of low birth weight, premature birth, and stillbirth among pregnant adolescents in Canada: a systematic review and meta-analysis. J Pediatr Adolesc Gynecol. 2021;34:530–537. doi: 10.1016/j.jpag.2021.03.003. [DOI] [PubMed] [Google Scholar]
- 35.Chen XK, Wen SW, Fleming N, et al. Teenage pregnancy and adverse birth outcomes: a large population based retrospective cohort study. Int J Epidemiol. 2007;36:368–373. doi: 10.1093/ije/dyl284. [DOI] [PubMed] [Google Scholar]
- 36.Wong SP, Twynstra J, Gilliland JA, et al. Risk factors and birth outcomes associated with teenage pregnancy: a Canadian sample. J Pediatr Adolesc Gynecol. 2020;33:153–159. doi: 10.1016/j.jpag.2019.10.006. [DOI] [PubMed] [Google Scholar]
- 37.Amjad S, MacDonald I, Chambers T, et al. Social determinants of health and adverse maternal and birth outcomes in adolescent pregnancies: a systematic review and meta‐analysis. Paediatr Perinat Epidemiol. 2019;33:88–99. doi: 10.1111/ppe.12529. [DOI] [PubMed] [Google Scholar]
- 38.Slattery MM, Morrison JJ. Preterm delivery. The Lancet. 2002;360:1489–1497. doi: 10.1016/S0140-6736(02)11476-0. [DOI] [PubMed] [Google Scholar]
- 39.Martin JA, Hamilton BE, Sutton PD, et al. Births: final data for 2005. Natl Vital Stat Rep. 2007;56:1–103. [PubMed] [Google Scholar]