Concurrent procedures during caesarean delivery and early postoperative deep vein thrombosis detection: a retrospective cohort study
This retrospective cohort study of 1,943 women found no significant association between concurrent procedures during caesarean delivery and early postoperative deep vein thrombosis detection, suggesting that the current RCOG practice of adding a uniform three-point risk increment for such procedures increases the number of women qualifying for prophylactic heparin without improving risk discrimination.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
Pregnancy and the immediate time after birth are natural states where a woman's blood becomes thicker and more prone to clotting, a biological safeguard designed to prevent excessive bleeding during delivery. However, this same protective mechanism can sometimes go too far, leading to dangerous clots that form in the deep veins of the legs, a condition known as deep vein thrombosis. If these clots break loose, they can travel to the lungs, causing a life-threatening blockage. Because of this risk, doctors use a scoring system to decide which new mothers need extra protection, usually in the form of daily blood-thinning injections. Cesarean delivery, which is major abdominal surgery, already carries a higher risk of these clots than a vaginal birth, so it automatically adds points to a woman's risk score. But a question has lingered in medical practice: if a surgeon performs an additional, unrelated operation during the same Cesarean surgery—such as tying off fallopian tubes to prevent future pregnancies or removing a fibroid from the uterus—does that extra work automatically make the patient even more at risk? Should that single extra step trigger a mandatory jump in the risk score, forcing more women to receive weeks of daily injections?
To answer this, researchers at the Maternal and Child Health Hospital of Hubei Province in China looked back at the records of nearly two thousand women who had Cesarean deliveries between January 2023 and January 2026. They focused on a specific group of 944 women who had at least one additional procedure performed while they were already on the operating table, comparing them to 999 women who had only the Cesarean delivery itself. The goal was to see if the women with the extra surgeries developed more blood clots in their legs shortly after the operation. To ensure they didn't miss any hidden clots, every single woman in the study underwent a specialized ultrasound scan of both legs about 24 hours after surgery, regardless of whether they felt any pain or swelling. This routine screening allowed the team to find clots that might otherwise have gone unnoticed until they caused serious problems later.
The results were clear and surprising. Among the women who had the additional procedures, about 1.7 percent were found to have a clot in their legs. Among the women who had only the Cesarean delivery, the rate was slightly lower at 1.4 percent. When the researchers adjusted for other factors that are known to increase clot risk, such as the mother's age and whether the baby was born early, the difference between the two groups vanished. The data showed no evidence that the extra surgery itself made a woman more likely to develop a clot in the first day after birth. The confidence in this finding was not absolute, as the number of clots found was relatively small, meaning the study could not completely rule out a very small increase or decrease in risk. However, the estimates hovered right around the middle, suggesting that the additional procedures did not independently drive up the danger of early clot formation.
The researchers then tested a different question: what would happen if doctors simply added three points to the risk score for every woman who had an extra procedure, as some interpretations of current guidelines might suggest? They ran a computer simulation to see how this rule change would affect patient care. The simulation showed that this uniform addition would push hundreds of women over the threshold where they would be prescribed at least ten days of blood-thinning injections. Specifically, 268 more women would be classified as high-risk and sent home with a prescription for these injections. However, the simulation also revealed that this change did not make the risk assessment system any better at actually predicting who would get a clot. The system's ability to distinguish between high-risk and low-risk patients did not improve; it simply labeled many more women as high-risk without finding more actual clots.
This suggests that while the extra surgeries might make the operation take longer or involve more blood loss, these factors did not translate into a higher rate of immediate blood clots in this group of women. The study indicates that automatically adding points to the risk score for every concurrent procedure might lead to a large number of women receiving unnecessary daily injections, which carry their own risks of bruising and bleeding, without providing a clear benefit in preventing clots. The researchers found that other factors, such as a mother being older or delivering a baby before 37 weeks, were more strongly linked to the development of clots than the presence of an additional surgery. Ultimately, the study supports the idea that risk assessment should remain nuanced and based on the full picture of a patient's health rather than a rigid rule that adds points for every extra step taken in the operating room. The authors conclude that while their findings do not justify ignoring current guidelines, they highlight a need for further, larger studies to determine if a more tailored approach to risk scoring could spare women from unnecessary treatment while still protecting those who truly need it.
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