In-Labour Cesarean Sections Linked to Increased Risk of Preterm Birth and Mid-Trimester Loss: Study Finds

The authors from King’s College London, St Thomas’ Hospital, London, United Kingdom, emphasize that cervical damage caused by cesarean procedures during labor is a key factor contributing to these risks. The perspective was published online in

PLOS Medicine on December 12, 2024.

The rate of cesarean sections has risen significantly over the past few decades, with one in five women globally now delivering by cesarean. In the UK alone, over one in three women give birth through cesarean delivery, and 24% of these are classified as emergency cesareans, with 5% being performed at full cervical dilation. Notably, in North America, cesareans performed at full dilatation have risen by 44% over the past decade. Factors such as changes in medical training, litigation fears, and cultural expectations have been identified as contributing to these trends.

Cesarean sections are often lifesaving; however, the procedure, especially when performed late in labor, has been associated with significant risks in future pregnancies. Studies suggest that women with a history of in-labour cesarean delivery face an increased likelihood of mid-trimester loss and spontaneous preterm birth (sPTB). Data from recent research show that these risks are especially elevated when cesarean delivery occurs at full cervical dilatation. In one study, women with a prior in-labor cesarean had a relative risk of 2.7 for recurrent sPTB and 5.65 for mid-trimester losses compared to women without this surgical history.

Cervical damage, specifically at the internal os during or following cesarean procedures, has been proposed as the underlying mechanism. This disruption weakens cervical integrity, impairing its ability to maintain a pregnancy in subsequent gestations. Mechanisms contributing to cervical damage include surgical trauma, healing responses, and scar positioning. Imaging studies like transvaginal ultrasound (TVUS) support these findings, showing that cesarean scars near or at the internal os can lead to a shortening cervix and subsequent preterm delivery risks.

Standard interventions such as transvaginal cerclage (TVC) have shown limited success in women with prior in-labour cesarean deliveries. This has led to increased consideration of alternative approaches like transabdominal cerclage (TAC), which involves placing a suture higher up, above the cervical damaged area. Recent studies suggest that TAC may significantly reduce the rates of sPTB compared to TVC.

The authors stress that as cesarean rates rise, healthcare professionals must address these risks through better training, imaging, and management strategies. There is an urgent need for research to explore optimal imaging protocols, risk assessments, and interventions to minimize cervical damage and improve outcomes for affected women. Recognizing cervical cesarean damage as a growing clinical issue can guide shared decision-making and improve both clinical practice and maternal health outcomes.

Reference:

van der Krogt L, Shennan A (2024) Cervical cesarean damage as a growing clinical problem: The association between in-labour cesarean section and recurrent preterm birth in subsequent pregnancies. PLoS Med 21(12): e1004497. https://doi.org/10.1371/journal.pmed.1004497