Sima Yeneabeba Tilahun, Magnus Maria Christine, Kvalvik Liv Grimstvedt, Morken Nils-Halvdan, Klungsøyr Kari, Skjærven Rolv, Sørbye Linn Marie
Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway.
Centre for Fertility and Health, Norwegian Institute of Public Health, Oslo, Norway.
Am J Obstet Gynecol. 2024 Jun;230(6):667.e1-667.e21. doi: 10.1016/j.ajog.2023.10.029. Epub 2023 Oct 19.
Previous studies have found that women who undergo cesarean delivery have fewer pregnancies. Cesarean delivery is also more common among women with lower fecundability. The potential role of cesarean delivery in reduced fecundability is not known.
This study aimed to assess the bidirectional relationship between cesarean delivery and fecundability.
This was a prospective cohort study based on data from the Norwegian Mother, Father, and Child Cohort study linked with the Medical Birth Registry of Norway. We estimated the fecundability ratio (per cycle probability of pregnancy) and relative risk of infertility (time to pregnancy ≥12 months) by mode of delivery in the previous delivery among 42,379 women. For the reverse association, we estimated the relative risk of having a cesarean delivery by fecundability (the number of cycles women needed to conceive) among 74,024 women.
The proportion of women with infertility was 7.3% (2707/37,226) among women with a previous vaginal delivery and 9.9% (508/5153) among women with a previous cesarean delivery, yielding an adjusted relative risk of 1.21 (95% confidence interval, 1.10-1.33). Women with a previous cesarean delivery also had a lower fecundability ratio (0.90; 95% confidence interval, 0.88-0.93) than women with a previous vaginal delivery. When assessing the reverse association between fecundability and cesarean delivery, we found that women who did not conceive within 12 or more cycles had a higher risk for cesarean delivery (adjusted relative risk, 1.57; 95% confidence interval, 1.48-1.66) than women who conceived within the first 2 cycles. The associations remained after controlling for sociodemographic and clinical risk factors and were observed across parity groups.
Among women with more than 1 child, those who had a previous cesarean delivery subsequently had a lower fecundability ratio and an increased infertility risk than those who had a vaginal delivery. However, women who needed a longer time to conceive were also more prone to be delivered by cesarean delivery, indicating a bidirectional relationship between cesarean delivery and fecundability. This could suggest a common underlying explanatory mechanism and that the surgical procedure itself may not or only partly directly influence fecundability.
既往研究发现，接受剖宫产的女性妊娠次数较少。剖宫产在生育力较低的女性中也更为常见。剖宫产在降低生育力方面的潜在作用尚不清楚。
本研究旨在评估剖宫产与生育力之间的双向关系。
这是一项前瞻性队列研究，基于挪威母亲、父亲和儿童队列研究的数据，并与挪威医疗出生登记处的数据相链接。我们在42379名女性中，根据前次分娩方式估算了生育力比率（每个周期的妊娠概率）和不孕的相对风险（妊娠时间≥12个月）。对于反向关联，我们在74024名女性中，根据生育力（女性受孕所需的周期数）估算了进行剖宫产的相对风险。
前次阴道分娩的女性中不孕女性的比例为7.3%（2707/37226），前次剖宫产的女性中为9.9%（508/5153），校正后的相对风险为1.21（95%置信区间，1.10 - 1.33）。前次剖宫产的女性生育力比率（0.90；95%置信区间，0.88 - 0.93）也低于前次阴道分娩的女性。在评估生育力与剖宫产之间的反向关联时，我们发现12个或更多周期内未受孕的女性进行剖宫产的风险（校正后的相对风险，1.57；95%置信区间，1.48 - 1.66）高于在前2个周期内受孕的女性。在控制了社会人口学和临床风险因素后，这些关联仍然存在，并且在不同产次组中均有观察到。
在有多个孩子的女性中，前次接受剖宫产的女性随后的生育力比率较低，不孕风险增加，高于前次阴道分娩的女性。然而，需要更长时间受孕的女性也更倾向于剖宫产分娩，这表明剖宫产与生育力之间存在双向关系。这可能提示存在一个共同的潜在解释机制，并且手术本身可能不会或仅部分直接影响生育力。
