An epidemiologic investigation of childbirth and postpartum health
Embargo Date
2026-08-19
OA Version
Citation
Abstract
Almost one-third of birthing people in the United States deliver via cesarean delivery each year. This high rate has been linked to high maternal morbidity and mortality rates in the United States. Contributors to cesarean delivery rates are numerous and can complicate studies investigating postpartum outcomes associated with cesarean deliveries. The goal of this dissertation was to examine patterns in cesarean delivery rates by pregnancy and labor characteristics, and to assess the association of delivery method with postpartum emergent hospital visit accounting for individual-level demographic and pregnancy factors as well as hospital level variables. The first study of this dissertation is a descriptive analysis of births in Massachusetts between 2011 and 2018. The objectives of this study were to understand the distribution of cesarean deliveries using the Robson Classification system and to identify associated conditions (and potential drivers) of cesarean delivery across Robson groups. The Robson classification system is recommended by the World Health Organization (WHO) and allows comparison of cesarean delivery rates across populations in a standardized method. Using data from the Pregnancy and Early Life Longitudinal data system (PELL), we analyzed patterns in maternal comorbidities and labor and delivery complications by Robson group. We found that while cesarean delivery rates, maternal risk factors, and labor and delivery complications followed similar patterns across Robson groups, there were notable discrepancies; in births with non-cephalic presentations (where cesarean delivery rates were high), maternal comorbidity rates matched lower cesarean risk groups like the nulliparous single term cephalic births. Maternal health researchers have focused on nulliparous, term, singleton, vertex (NTSV) primary cesarean deliveries as potentially avoidable and these are typically the focus of interventions designed to reduce the cesarean delivery rate in the United States. We discovered that nearly half of these births (with no induction and no planned cesarean) had labor complications, suggesting cesarean deliveries that aren’t all necessarily preventable.
Our second study was an analysis of the association between cesarean delivery and postpartum emergent hospital visit within one year after delivery. Using PELL, we analyzed how different indications for cesarean delivery modify the absolute effect of cesarean delivery on postpartum emergent hospital visit. We found that overall, cesarean deliveries are associated with an increased risk of postpartum emergent hospital visit. Further, this effect differed across indication for cesarean delivery. Cesarean delivery among birthing people with no documented indication, cesarean delivery compared to vaginal delivery was not associated with higher postpartum emergent hospital visit rates. The same was true for individuals with a uteroplacental/anatomic complication. However, among individuals who experienced a labor complication, a fetal condition, or who had documented acute or chronic disease, cesarean delivery was associated with an increased risk of postpartum emergent hospital visit. These results show the importance of understanding cesarean delivery indication when estimating how cesarean deliveries impact postpartum health.
The final study in this dissertation examined the association between trial of labor after cesarean (TOLAC), vaginal birth after cesarean delivery (VBAC), and repeat cesarean delivery with 90-day postpartum emergent hospital visit. We used PELL data to estimate the effect of TOLAC on postpartum emergent hospital visit, compared to elective repeat cesarean delivery (ERCS). We then estimated the effect of vaginal birth after cesarean delivery (VBAC) compared to unsuccessful TOLAC on postpartum emergent hospital visit and examined if hospital volume modified the observed association. We found that TOLAC was associated with a reduced risk of postpartum emergent hospital visit compared to ERCS. Similarly, VBAC was protective against postpartum emergent hospital visit compared to unplanned repeat cesarean. These results affirm VBAC and TOLAC as protective against rehospitalization in the 90 days postpartum.
Description
2025