Section for epidemiology and medical statistics
New dissertation

Caesarean delivery and women’s health—Beyond the incision

Yeneabeba Tilahun Sima defends her PhD on February 22nd, 2024, at the University of Bergen with the thesis: "Caesarean Delivery and Women’s Health: Population-Based Studies: Trends, Offspring Birthweight, Fecundability and Maternal Cardiovascular Disease Mortality".

Yeneabeba Tilahun Sima - picture dissertation
Sage Wyatt, UIB

Main content

Caesarean delivery (CD) is a life-saving procedure. However, higher rates of CD have been linked with adverse maternal outcomes such as preterm birth, miscarriage, and infertility. By using population-based data, we have investigated CD trends in Norway in relation to sociodemographic factors and the subsequent consequences of CD for women's health, focusing on women’s fecundability (their ability to conceive) and cardiovascular disease (CVD) mortality.

We found an increasing trend of CD among first-time mothers since 1967, though it stabilized after 2008. Despite the increase in the number of women giving birth at an advanced age, CD declined among women aged 35 and older. The overall rise in CD rates cannot be merely attributed to the shift in the age of first-time mothers.

We also explored the role of CD on women’s fecundability in subsequent pregnancies using data from the Norwegian Mother, Father, Child cohort. We found that women with a prior CD experienced reduced fecundability in their next pregnancy compared to those with prior vaginal deliveries. Additionally, women who took longer to conceive were more likely to undergo a CD. Hence, we believe associations between CD and reduced fecundability may not be causal, but potentially due to common underlying mechanisms, and that the surgical procedure may not directly influence fecundability.

By linking the Medical Birth Register of Norway with the Norwegian Cause of Death Registry, we followed 753,244 mothers with two consecutive term births from 1967 to 2020. The study revealed that an increase in offspring birthweight from the first to second birth was associated with a decrease in maternal CVD mortality. This trend was consistent for both spontaneous- and iatrogenic births. Including information from subsequent births revealed heterogeneity in maternal mortality, highlighting the importance of considering pregnancies beyond the first.

Yeneabeba Sima grew up in Addis Ababa, Ethiopia, and graduated as a medical doctor from Mekelle University. She has a master’s degree in International Community Health from the University of Oslo (2018). She completed her PhD at the University of Bergen, with funding from the European Research Council. The main supervisor is Associate Professor Linn Marie Sørbye. Co-supervisors are Professor Rolv Skjærven, Associate Professor Liv Grimstvedt Kvalvik and Professor Nils-Halvdan Morken.