Perinatal Care Measures Are Incomplete If They Do Not Assess The Birth Parent-Infant Dyad As A Whole

Abstract

Measures of perinatal care quality and outcomes often focus on either the birth parent or infant. We used linked vital statistics and hospital discharge data to describe a dyadic measure (including both the birth parent and infant) for perinatal care during the birth hospitalization. In this 5-state cohort of 2010-2018 births, 21.6% of birth parent-infant dyads experienced at least one complication and 9.6% experienced a severe complication. Severe infant complications were 8 times more prevalent than severe birth parent complications. Among birth parents with a severe complication the co-occurrence of a severe infant complication ranged from 2%-51%. Whereas, among infants with a severe complication the co-occurrence of severe birth parent complication was rare, ranging from 0.04%-5%. These data suggest that measures, clinical interventions, public reporting, and policies focused on either the birth parent or infant are incomplete in their assessment of a healthy dyad. Thus, clinicians, administrators, and policymakers should evaluate dyadic measures, incentivize positive outcomes for both patients (parent and infant), and create policies that support the health of the dyad.

Introduction

With more than 3.6 million births in the United States in 2021, childbirth remains one of the most common indications for hospitalization.(1) With rising rates of maternal mortality,(2) severe maternal morbidity (SMM),(3) and preterm birth(4), there has been increased attention to developing validated, endorsed perinatal care quality and outcome measures during the birth hospitalization. These quality measures, including those endorsed by the National Quality Forum, focus on specific outcomes, processes, and screening for either the birth parent or infant. For the birth parent, these measures include cesarean birth rates, while for the infant they include health-care associated blood stream infections and exclusive breastmilk feeding.(5,6) In some clinical scenarios, birth parent and infant quality measures may be in conflict, such as 1) a cesarean birth in the setting of neonatal distress, which is associated with a higher risk of infections for the birth parent or 2) a medically-indicated preterm birth for the health of the birth parent, which places the infant at increased risk of preterm-associated morbidities.(7,8)

Adoption and reporting of perinatal care quality measures and outcomes have influenced clinical level of care guidelines(9,10), informed public health goals(11), and fueled public funding of initiatives to reduce perinatal complications such as maternal mortality review committees (12,13) and local and state collaborative-supported quality improvement efforts.(14,15) In addition, perinatal care measures and outcomes are used by stakeholders to assess the quality of hospital care; to inform patients about hospital outcomes through the publicly reported data; and to guide reimbursement and payment strategies, such as value-based payment methods.(6)

However, most quality measures and outcomes are condition- or patient-specific and focus on the health and care of either the birth parent or infant, not the birth parent-infant dyad as a collective entity.(16) While the birth parent and infant are two individual and independent patients, their physical and mental health, care, and outcomes are inextricably co-dependent. High-risk pregnant patients with pre-existing or pregnancy-associated conditions are more likely to have high-risk infants who are born prematurely or require neonatal intensive care.(17-21) Among high-risk infants, SMM may be an independent risk factor for increased neonatal hospital costs, length of stay, and infant mortality.(22,23) Similarly, high-risk infants have birth parents at greater risk of serious morbidities.(24-26) The health status of one member of the birth parent-infant dyad can have downstream effects on important health outcomes and behaviors that impact both the parent and infant, including postpartum depression, postpartum posttraumatic stress, and breastfeeding.(27-30) Furthermore, the range of downstream effects may be undercounted due to poor data correlation in hospital rates of severe maternal and infant morbidities.(31) There are limited studies that compare the co-occurrence of outcomes at either the patient or hospital level, and thus the impact of a dyadic measure cannot be assessed. Quality measures and outcomes that consider only the birth parent or only the infant are incomplete and insufficient as they do not account for the birth parent infant-dyad as a whole, but are often the only option available with the current data infrastructure and siloed health systems and clinical specialties. Patients desire assessments of pregnancy and childbirth that reflect a favorable outcome for the birth parent and their infant, holistically.(32) The integration of perinatal dyadic outcome measures into the evaluation of hospital care quality and perinatal care policies on a local, state, and national level may improve perinatal care delivery for the birth parent infant-dyad.

To support the shift from individual to dyadic measures in perinatal care and research, the objective of this study was to examine the frequency, overlap, and co-occurrence of any and severe perinatal complications during the childbirth hospitalization for the birth parent and infant separately and for the birth parent-infant dyad as a whole. In this study we examined three types of perinatal complications; those affecting pregnancy [preterm birth], birth parent, and infant. We hypothesized that there are dyads who may experience one of these three types of complications and others who may experience all three. Through this analysis we sought to examine these experiences in order to quantify differences between single patient (infant or birth parent) and dyadic measures of care.

Methods

Data and Study Population

This is a retrospective observational study of hospital-based births in California (January 1, 2010-December 31, 2018), Michigan (January 1, 2010-December 31, 2018), Oregon (January 1, 2010-December 31, 2018), Pennsylvania (January 1, 2010-December 31, 2014), and South Carolina (January 1, 2010-December 31, 2018) using vital statistics linked to administrative hospital discharge data. The vital statistic data, birth and death certificates, are linked to hospital discharge data for the birth parent and infant. Vital statistics data include characteristics such as birth parent age and education as well as infant sex, gestational age, and birth weight. Hospital discharge data include International Classification of Diseases (ICD) and Current Procedural Terminology (CPT) codes associated with the hospitalization for childbirth and capture pre-existing and pregnancy associated conditions (e.g., diabetes mellitus and gestational diabetes) as well as perinatal complications (e.g., SMM, postpartum hemorrhage, infant severe intraventricular hemorrhage). Study outcomes and variables, respective data sources, and associated ICD and CPT codes, if applicable, are listed in Appendix Exhibit A1.(33)

Linkage of birth parent and infant data was performed by the individual states prior to distribution to the research team. Using previously established and published methods, the birth parent-infant match rate was 94.8%.(34) A table of birth parent and infant characteristics among matched and unmatched records is included in the Appendix (Exhibit A2).(33) Unlinked data are often missing a hospital identifier on the birth certificate, suggesting birth outside of a hospital (e.g., home birth or birthing center). Given the focus on dyadic outcomes, unmatched records were excluded.

Matched birth parent-infant dyads were included if the infant was born between 24 and 44 weeks of gestation, the birth weight was between 400g and 8000g and did not exceed five standard deviations for the mean for gestational age given potential errors in the birth weight or gestational age variables,(35) and the birth occurred in a hospital with ≥10 births/year. The cohort identification flow diagram is included in the Appendix (Exhibit A3).(33) This study was reviewed and approved by the local Institutional Review Board and the Human Research Committees at each of the states that related data for this study.

Outcomes and Variables

The primary outcomes were a composite of 1) any and 2) severe perinatal complications. Perinatal complications were categorized into three types: pregnancy, birth parent, and infant. Given that preterm birth, whether spontaneous or medically-indicated, has potential health implications for both the birth parent and infant, it was considered a pregnancy complication. The composite outcome of any perinatal complication included any preterm birth (<37 weeks of gestation); the birth parent complications of mortality during the birth hospitalization, SMM (a composite of 20 indicators which did not include blood product transfusion)(36), birth parent intensive care unit (ICU) admission, perinatal infection, postpartum hemorrhage, 3^rd or 4^th degree laceration; and the infant outcomes of mortality during the birth hospitalization, severe (e.g. severe asphyxia, organ failure, and septic shock) or moderate (e.g., respiratory distress syndrome, bacteremia) unexpected term newborn complications (37), neonatal intensive care unit (NICU) admission, and any preterm morbidity (severe intraventricular hemorrhage [defined as grade III or IV], necrotizing enterocolitis, retinopathy of prematurity requiring surgery, and bronchopulmonary dysplasia). The composite outcome of severe perinatal complications included: 1) preterm birth (≤34 weeks of gestation); 2) severe birth parent complications (mortality, SMM, ICU admission); and 3) severe infant complications (mortality, severe unexpected term newborn complications, NICU admission, and any preterm morbidity). As previously described, established, and endorsed by the National Quality Form, unexpected newborn complications, both severe and moderate, were measured using ICD codes and assessed among term (born at ≥37 weeks), singleton infants with a birth weight ≥2500g as this measure was developed to report outcomes of healthy term infants without preexisting conditions.(37) The individual components of the composite outcomes were constructed using variables present in the vital statistics data or ICD and CPT codes from the hospital discharge data, which are listed in the Appendix Exhibit A1.(33) Complications were examined as a composite, by type (pregnancy, birth parent, and infant), and individually.

Characteristics of the birth parent-infant dyad were examined, including birth parent age, race/ethnicity, insurance type, education attained, pre-existing and pregnancy-associated conditions, including chronic hypertension, pregnancy induced hypertension and pre-eclampsia, pre-existing and gestational diabetes, placenta previa and multiple gestation, as well as cesarean birth, infant sex, and birth weight.

Analysis

We examined the proportion of dyads who experienced perinatal complications, the overlap of complications by type, and the frequency of co-occurrence of severe perinatal complications across dyads. We compared the distribution of covariates within dyads with and without any and severe perinatal complications using standardized differences. Standardized differences compare proportions—formulated as a series of one-vs-rest comparisons for categorical variables in units of the pooled standard deviation.(38) A standardized difference of >0.1 indicates imbalance.(39) Unlike t tests or chi-squared tests, which may indicate statistically significant dissimilarities (small p-values) in large cohort studies, standardized differences are not influenced by sample size and are useful for assessing baseline differences in this context.(40)

The analysis has limitations. First, only five states were included, which are not nationally representative, but are geographically diverse and include populations with a range of demographic characteristics. Second, NICU admission is undercounted in birth certificate data, which is a source of misclassification bias and suggests more dyads may experience complications than reported. Third, there was no statistical adjustment or a weighting scheme for outcomes, which reflects the descriptive study design.

Results

Among 6,657,519 dyads meeting inclusion criteria, 1,438,380 (21.6%) had any perinatal complication (pregnancy, birth parent or infant) and 640,405 (9.6%) had a severe perinatal complication (pregnancy, birth parent or infant). Dyads experiencing any perinatal complication were more likely to have a birth parent who was non-Hispanic Black, with pre-existing or pregnancy-associated comorbidities, multiple gestation, or a cesarean birth (Appendix Exhibit A4).(33) Similar differences in characteristics were observed among dyads experiencing a severe perinatal complication (Appendix Exhibit A5).(33)

The proportion of pregnancies with any pregnancy, birth parent or infant complication was similar (9.0%, 8.8%, and 9.9%, respectively). However, severe complications were most frequent among infants (severe pregnancy complications: 3.7%, severe birth parent complications: 1.1%, severe infant complications: 8.2%) (Appendix Exhibit A6). Exhibit A6 also shows the frequency of complications by type and individually. For the birth parent, SMM was the most common individual severe complication (0.7%) and postpartum hemorrhage was the most common individual complication (3.7%). Among infants, NICU admission was the most common complication among both severe and any complications (7.3%). From 2010 to 2018 the proportion of dyads experiencing any birth parent or infant complication increased from 8.0% to 9.4% and from 9.1% to 10.6%, respectively. Similarly, severe birth parent and infant complications increased from 0.9% to 1.3% and from 7.7% to 8.6%, respectively. Any and severe pregnancy complications remained similar over time (any: 9.2% in 2010 and 2018, severe: 3.6% in 2010 and 3.7% in 2018).

There was limited overlap among dyads experiencing more than one complication type (pregnancy, birth parent or infant). Among the 21.6% of dyads experiencing any perinatal complication, 16.1% had one type of complication whereas only 0.59% experienced all three types (Exhibit 1). The pattern was similar with severe perinatal complications: among the 9.6% of dyads experiencing severe complications, 6.5% had one type of complication and only 0.19% experienced all three types (Exhibit 2).

EXHIBIT 1. Overlap of Any Perinatal Complications for the Pregnancy, Birth Parent, and Infant.

Source/Notes: Authors’ analysis of linked vital statistics and hospital discharge data from five states, 2010-2018.

EXHIBIT 2. Overlap of Severe Perinatal Complications for the Pregnancy, Birth Parent, and Infant.

Source/Notes: Authors’ analysis of linked vital statistics and hospital discharge data from five states, 2010-2018.

When examining individual complications, among birth parents with a severe complication, the co-occurrence of a severe infant or pregnancy complication ranged by condition from 2% (e.g., severe unexpected term newborn complications or any preterm morbidity among birth parents with SMM) to 51% (e.g., NICU admission among birth parents who died)(Exhibit 3). Among infants with a severe complication, the co-occurrence of a severe birth parent complication varied by condition but was in general less common than the overlap among parents with severe complications. Overlap between infants with a severe complication having a birth parent with a severe complication ranged from 0.04% (e.g., birth parent death among infants admitted to the NICU or with severe unexpected newborn complications) to 5% (e.g., birth parent SMM among infants who died or had any preterm morbidity)(Exhibit 4).

EXHIBIT 3. Co-occurrence of severe infant and pregnancy complications among birth parents with severe complications.

Source/Notes: Authors’ analysis of linked vital statistics and hospital discharge data from five states, 2010-2018.

EXHIBIT 4. Co-occurrence of severe birth parent complications among infants and pregnancies with severe complications.

Source/Notes: Authors’ analysis of linked vital statistics and hospital discharge data from five states, 2010-2018.

Discussion

This study found that 1,438,380 dyads - nearly 22% of dyads hospitalized for childbirth - experienced a perinatal complication across 5 states. The overlap of different types of complications within the dyad was infrequent, illustrating that measures focused on either the birth parent or the infant do not adequately account for adverse events that occur in the other half of the birth parent-infant dyad. The lack of co-occurrence is particularly evident among the most severe complications, such as birth parent or infant death.

The optimal childbirth outcome is a healthy infant and birth parent, a priority among many professional groups and organizations.(41) For example, the International Consortium for Health Outcomes and Measurement has proposed a set of 26 outcome measures capturing the care of the birth parent and infant during pregnancy through six months postpartum.(41) Benefits of this set of measures is that it is comprehensive over time, includes patient-reported outcomes and experiences, and has been deemed applicable to perinatal care by multiple stakeholders, across disciplines and specialties.(32,42) Yet, collating, reporting, and integrating a large number of measures that are collected longitudinally from multiple data sources (e.g., mortality registries and patient surveys) is resource intensive and requires significant buy in, from individual patients to national organizations.(43) A similar undertaking in the United States where efforts to coordinate data reporting at local, state, and national levels can be challenging given the large number of diverse and independent health systems with differing medical record systems and payor models would be complex.(43)

In many childbirth settings, particularly large volume (>2000 births/year) teaching hospitals (members of the Council on Teaching Hospitals or report a medical school affiliation to the American Medical Association) where the majority of births in the United States occur,(44) the organization and care of the birth parent and infant are separately managed, administered, and documented in the inpatient and outpatient setting. Care for birth parents is frequently led by obstetricians, and care for infants led by pediatricians; each type of specialist is guided by different clinical guidelines and is focused on their respective patients.(9,10) This is evident in the maternal and neonatal level of care guidelines, which were developed in isolation and only consider one half of the dyad.(16) This siloed focus is also reflected in commonly reported outcomes and perinatal care quality improvement efforts.(5,6,12,13) While breastfeeding, which may be viewed as a dyadic outcome, is commonly supported and promoted through institutional baby-friendly initiatives,(45) it is only one aspect of dyadic health and may not be indicated or preferred by all birth parents, such as those with certain infections, a history of breast surgery, or other barriers. Ideally, the organization and assessment of perinatal care delivery reflect the care needs of both the birth parent and infant, facilitating dyadic outcomes that are relevant and applicable to all patients, as well as clinicians, researchers and policymakers.

The dyadic measure we examined focuses on the birth hospitalization and has some advantages. First, similar to SMM and unexpected term newborn complications, this measure uses commonly collected data, which decreases the need for new data infrastructure and makes the examination and potential reporting of such measures accessible. This is complicated, however, by the reality that birth parent and infant records are not routinely linked or publicly available nationally.(43,46) Second, focusing on the birth hospitalization provides insight into a period of high health system contact where intervention is feasible. A dyadic outcome that is accessible with respect to measurement and actionable with respect to the context (e.g., childbirth hospitalization) has potential to inform the integration of future dyadic measures of care. Further, opportunities to improve consistent outcome reporting across hospitals and health systems is essential to value-based perinatal care. This dyadic measure may provide an opportunity for care assessment that is meaningful to patients, accessible to hospital administrators, and relevant to public health leaders and policymakers looking to improve perinatal care and outcomes.

As rates of maternal mortality and morbidity have risen in the United States, there has been a renewed focus on maternal care and outcomes among policymakers and researchers.(47) In June 2022 the White House released a Blueprint for Addressing the Maternal Health Crisis describing specific actions planned to improve maternal health.(48) One action area is maternal mental health, which has dyadic underpinnings as evidence has consistently shown a relationship between infant clinical complications with parental psychological stress and need for mental health services.(49,50) There are also multiple national initiatives working to enhance data in women’s health research.(51) The measure we describe aligns with the principles of these initiatives by using linked data to assess complications across the dyad to enhance outcome surveillance. The Centers for Medicare & Medicaid Services are actively establishing a “Birthing-Friendly” designation, a public-facing designation signifying high-quality and safe maternal care.(52) A meaningful “Birthing-Friendly” hospital definition is likely one that includes systems and practices that support high-quality, safe, and equitable care for both the birth parent and the infant. Integrating dyadic measures into such definitions does not overshadow the importance of each individual patient, but reflects a holistic view of health for the birth parent and infant. Reporting the dyadic composite and individual components may be beneficial in helping clinicians, hospitals, or policymakers identify areas for improvement, develop change efforts, and update policies.

The data used for this study and its results contribute useful information for policymaking, but there are limitations on the implications that can be drawn, and many opportunities for further development. These data may not fully capture the health and care of the dyad. While multiple data sources allow for internal crosschecking and prioritization of the most reliable variables, perinatal complications are likely underreported in this study. Furthermore, while a variety of birth parent, pregnancy, and infant complications were included in the composite outcome, the potential inclusion of other complications or outcomes may further improve dyadic measures. Nationwide linkage of vital statistics and hospital discharge data are not currently available and are resource intensive. Yet, a recent review found published studies using linked vital statistics and Medicaid data from 22 states and emphasized the value of these data to advance public health research and policy.(46) With a similar number of states that have previously or are able to link vital statistics with all hospital discharge data, increasing data availability and utility may encourage future national data linkage efforts. The findings and these baseline data create a foundation on which future work can further develop dyadic measures.

In conclusion, complications for the birth parent-infant dyad are common during the birth hospitalization. The limited overlap of complications described emphasizes the importance of integrating dyadic outcomes into clinical care, research, and policy in order to support the health of parents, infants, their families, and communities.