Childbirth study examines first-time deliveries and link between cesarean section and subsequent fertility

In the United States, more than 30% of babies are surgically delivered via cesarean sections. A new Penn State College of Medicine study, published in the American Medical Association’s JAMA Network Open, examines first-time births to see if C-section deliveries impact a woman’s ability to conceive later and if C-sections impact subsequent births.

The study, Association Between Mode of First Delivery and Subsequent Fecundity and Fertility, examines if women who have their first child via a C-section experience decreased fertility compared to women who deliver their first babies vaginally.

Led by Kristen Kjerulff, MA, PhD, the study looks at 2,021 women, 18 to 35 years old, who participated in Penn State’s First Baby Study and had their first child during 2009 to 2011. Women were interviewed throughout their pregnancies and at defined intervals up to 36 months postpartum. Data analysis for this study took place in 2019 and early 2020.

Of the participants, 599 women delivered their first child via a C-section. During the 36-month postpartum period, researchers examined whether participants conceived after unprotected intercourse, and if women had any additional children during this timeframe.

Findings show that mothers who had their first child via a C-section were less likely to conceive after unprotected intercourse, compared to women who had vaginal births. Of participants, 42% of those who had their first child via a C-section reported at least one subsequent birth during the 36-month follow-up period. This compares to 50% of those who had their first child delivered vaginally. Women who delivered via a C-section had a higher rate of subsequent stillbirths than women who had delivered vaginally.

Regarding fertility during the follow-up period, 76% of women who delivered their first child vaginally were able to conceive during this time, compared to 68% of mothers who had delivered their first child via a C-section.

This study does have limitations. Further studies could benefit from a larger scope and collect data over a longer period of time. This study only included women from Pennsylvania, and participants were only monitored for a three-year period after having their first baby.

This study was supported by grant number R01 HD052990 from the Eunice Kennedy Shriver National Institute of Child Health & Human Development, National Institutes of Health.

For this study, Dr. Kjerulff was joined by Ian Paul, MD, MSc, professor of pediatrics and public health sciences; Carol Weisman, PhD, distinguished professor emeritus of public health sciences, obstetrics and gynecology and health policy and administration; Marianne M. Hillemeier, PhD, MPH, professor of health policy and administration; Ming Wang, MS, PhD, associate professor of public health sciences; Richard Legro, MD, professor and chair of obstetrics and gynecology and professor of public health sciences; and John Repke, MD, professor of obstetrics and gynecology.

Read more about the work in this New York Times article.

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