Department of Obstetrics and Gynecology, MBBM Foundation at San Gerardo Hospital, University of Milan-Bicocca School of Medicine and Surgery, Monza, Italy.
J Ultrasound Med. 2022 Jan;41(1):123-133. doi: 10.1002/jum.15687. Epub 2021 Mar 5.
The safest mode of delivery in low-lying placenta is debatable. Little is known about outcomes in low-lying placenta resolved during the late third trimester. We compare outcomes of women with persistent versus resolved low-lying placenta.
A retrospective analysis on a prospective cohort of women with low-lying placenta confirmed at 28-30 weeks sonography (01/2009 to 03/2018). Women were followed up serially every 2 to 3 weeks until delivery to assess the placental edge-to-internal os distance (IOD), and included if scan was performed within 28 days before delivery.
There were 86 women: in 21 the low-lying placenta resolved, whereas in 65 persisted (n = 15 IOD 1-10 mm, n = 50 IOD 11-20 mm). Antepartum bleeding associated with higher rates of urgent cesarean delivery in 1-10 mm (P = .041) but not in 11-20 mm (P = 1.000) and >20 mm (P = .333). Among women with IOD >10 mm allowed to labor, vaginal delivery occurred in 76.7% (11-20 mm) and 94.1% (>20 mm) (P = .155), with no difference according to parity (70% and 80% in multiparas, P = .696; 60% and 72.7% in nulliparas, P = .698). Severe PPH (P = .922) and hemoglobin drop (P = .109) were similar among groups. Women with IOD 11-20 mm and >20 mm and vaginal delivery bled less than women with similarly located placenta and cesarean delivery (P = .009 and P = .048).
Women with IOD >10 mm have high chances of deliver vaginally with no further increase of their hemorrhagic risk. Success of vaginal delivery is independent of parity and antepartum bleeding. Labor should be managed in an adequate hospital setting.
低位胎盘的最安全分娩方式仍存在争议。对于在妊娠晚期消退的低位胎盘，其结局知之甚少。我们比较了持续性和消退性低位胎盘孕妇的结局。
对 2009 年 1 月至 2018 年 3 月期间在 28-30 周超声检查中确诊为低位胎盘的前瞻性队列进行回顾性分析。每隔 2-3 周对孕妇进行连续监测，以评估胎盘边缘至子宫内口的距离（IOD），如果在分娩前 28 天内进行了扫描，则将孕妇纳入研究。
共纳入 86 名孕妇：21 名孕妇的胎盘位置消退，65 名孕妇的胎盘位置持续存在（15 名孕妇的 IOD 为 1-10mm，50 名孕妇的 IOD 为 11-20mm）。1-10mm 的胎盘前置出血与紧急剖宫产率升高相关（P=0.041），但在 IOD 为 11-20mm（P=1.000）和>20mm（P=0.333）的孕妇中无差异。对于允许经阴道分娩的 IOD>10mm 的孕妇，阴道分娩率为 76.7%（11-20mm）和 94.1%（>20mm）（P=0.155），且与产次无关（经产妇中分别为 70%和 80%，P=0.696；初产妇中分别为 60%和 72.7%，P=0.698）。严重产后出血（P=0.922）和血红蛋白下降（P=0.109）在各组间无差异。IOD 为 11-20mm 和>20mm 且行阴道分娩的孕妇出血量少于同样位置胎盘且行剖宫产分娩的孕妇（P=0.009 和 P=0.048）。
IOD>10mm 的孕妇经阴道分娩的机会很高，且不会增加其出血风险。阴道分娩的成功率与产次无关，与产前出血无关。应在适当的医院环境下进行分娩管理。
