From the Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, Texas.
Obstet Gynecol. 2010 Sep;116(3):595-600. doi: 10.1097/AOG.0b013e3181ea2deb.
To estimate the relationship between cervical length and hemorrhage leading to preterm delivery in women with placenta previa.
Between October 2007 and May 2009, transvaginal cervical-length measurements were obtained in all singleton pregnancies with placenta previa identified at or beyond 24 weeks of gestation. Only women who delivered liveborn or stillborn neonates at our hospital and had placenta previa confirmed at delivery were included. Cervical length of 30 mm or less was considered short. Clinicians were blinded to cervical-length measurements. Chi-square and logistic regression were used for analysis.
Of 89 identified women with placenta previa at initial ultrasonography, 68 had placenta previa at delivery, and 29 (43%) of these had a short cervix. Gestational age at cervical-length measurement was 32+/-4 weeks in women with a short cervix and 33+/-2 weeks in those with a longer cervix (P=.4). Women with previa and a short cervix were more likely to require delivery for hemorrhage, 79% compared with 28%, and to deliver preterm, 69% compared with 21% (both P<.001). Tocodynamometer evidence of regular uterine contractions was more common with a short cervix than with a longer cervix, 69% compared with 21% (P<.001). Conversely, 64% with a cervical length greater than 30 mm had no bleeding episodes and progressed to term.
In pregnancies with placenta previa, a third-trimester cervical length of 30 mm or less is associated with increased risk for hemorrhage, uterine activity, and preterm birth.
II.
评估胎盘前置孕妇的宫颈长度与早产出血的关系。
2007 年 10 月至 2009 年 5 月，对所有在 24 周及以后经阴道超声检查诊断为前置胎盘的单胎妊娠孕妇进行宫颈长度测量。仅纳入在我院分娩的活产或死产新生儿且分娩时证实为前置胎盘的孕妇。宫颈长度＜30mm 定义为宫颈短。临床医生对宫颈长度测量结果不知情。采用卡方检验和 logistic 回归进行分析。
89 例初始超声检查诊断为前置胎盘的孕妇中，68 例孕妇在分娩时仍为前置胎盘，其中 29 例（43%）的宫颈较短。宫颈长度较短的孕妇进行宫颈长度测量时的妊娠周数为 32+/-4 周，宫颈长度较长的孕妇为 33+/-2 周（P=.4）。宫颈较短的前置胎盘孕妇更可能因出血而需要分娩，发生率为 79%，而宫颈较长的孕妇为 28%（均 P<.001）；更可能早产，发生率为 69%，而宫颈较长的孕妇为 21%（均 P<.001）。宫颈较短的孕妇比宫颈较长的孕妇更常见规律宫缩的宫缩仪证据，发生率分别为 69%和 21%（P<.001）。相反，64%的宫颈长度大于 30mm 的孕妇无出血发作并进展至足月。
在胎盘前置的孕妇中，妊娠晚期宫颈长度＜30mm 与出血、子宫活动和早产风险增加相关。
II 级。
