Japanese Organization of Prevention of Preterm Delivery (JOPP), Tokyo, Japan.
Department Obstetrics and Gynecology, Nippon Medical School, Tokyo, Japan.
J Matern Fetal Neonatal Med. 2022 Dec;35(25):8012-8018. doi: 10.1080/14767058.2021.1940935. Epub 2021 Jun 28.
Vaginal progesterone reduces the preterm birth frequency among high-risk women with a cervical length ≤25 mm at midtrimester. However, the strategy may promote no substantial reduction in overall preterm birth rates, because such high-risk women are only approximately 2% of all pregnant women, which restrict the number of participants. Our purpose was to determine whether prophylactic vaginal progesterone administration can preserve cervical length and reduce preterm birth rates among women with mild cervical shortening.This multicenter, parallel-arm, double-blind, randomized, placebo-controlled trial involved vaginal progesterone administration (200 mg daily from 16 to 33 weeks of gestation) among asymptomatic women with a singleton pregnancy and a sonographic cervical length of 25 to <30 mm between 16 and 23 weeks of gestation. The primary and secondary endpoints were cervical shortening rates at 34 weeks of gestation and preterm birth rates, respectively. The trial was registered at the University Hospital Medical Information Network (UMIN000013518) in Japan.Between April 2014 and March 2018, 119 women were randomly assigned to the progesterone group ( = 59) and the placebo group ( = 60). No significant differences in the frequency of women with a cervical length ≥20 mm at 34 weeks of gestation were observed between both groups. All preterm births occurred after 34 weeks of gestation, except for one patient in the placebo group. The progesterone group had a lower rate of preterm birth before 37 weeks than the placebo group (3.4% vs. 15.0%, respectively; < .05).Despite having no effect on preserving cervical length, prophylactic vaginal progesterone administration reduced preterm birth frequency among women with mild cervical shortening. Our results are suggesting that women with mild cervical shortening are at risk for late preterm birth and the need for expanding progesterone treatment indications to include not only high-risk but also low-risk populations.
阴道孕酮可降低中孕期宫颈长度≤25mm 的高危孕妇的早产发生率。然而，这种策略可能不会显著降低整体早产率，因为这类高危孕妇仅占所有孕妇的 2%左右，这限制了参与者的数量。我们的目的是确定预防性阴道孕酮给药是否可以维持宫颈长度并降低宫颈缩短孕妇的早产率。
这项多中心、平行臂、双盲、随机、安慰剂对照试验纳入了 16-23 孕周、超声测量宫颈长度为 25-<30mm、无任何症状且单胎妊娠的孕妇，给予阴道孕酮（每天 200mg，从 16 孕周用到 33 孕周）。主要和次要终点分别为 34 孕周时的宫颈缩短率和早产率。该试验在日本大学医院医疗信息网络（UMIN000013518）注册。
2014 年 4 月至 2018 年 3 月，共有 119 名女性被随机分配到孕酮组（n=59）和安慰剂组（n=60）。两组在 34 孕周时宫颈长度≥20mm 的女性比例无显著差异。所有早产均发生在 34 孕周之后，除了安慰剂组的一名患者。孕酮组在 37 孕周之前的早产率低于安慰剂组（分别为 3.4%和 15.0%；<0.05）。
尽管预防性阴道孕酮给药对维持宫颈长度没有影响，但可降低宫颈缩短孕妇的早产频率。我们的研究结果表明，宫颈缩短程度较轻的孕妇有发生晚期早产的风险，需要扩大孕酮治疗的适应证，不仅包括高危人群，还包括低危人群。
