探讨一次性球囊宫颈扩张器(以下简称为球囊)对单纯性临界羊水过少(IBO)与单纯性羊水过少(IO)足月妊娠产妇的引产效果及其妊娠结局。

选择2018年6月至2020年6月，于江苏省苏北人民医院采取球囊引产的346例足月妊娠产妇为研究对象。根据晚孕期羊水指数(AFI)值，将其分为IBO组(n＝135，5 cm<AFI值≤8 cm)，IO组(n＝38，AFI值≤5 cm)与对照组(n＝173，AFI值正常)。观察3组产妇放置球囊时孕龄，放置前、后宫颈Bishop评分，促宫颈成熟有效率，阴道分娩率、中转急诊剖宫产术分娩率，第一产程时长，不良妊娠结局(羊水胎粪污染、产后发热、产后出血)与球囊相关并发症发生情况及新生儿结局等，并采用单因素方差分析、Kruskal-Wallis H检验、χ²检验对3组受试者的上述指标进行总体比较，进一步两两比较，采用最小显著性差异(LSD)-t检验或Bonferroni法调整检验水准(α′＝0.05/3＝0.017)。3组产妇的年龄、孕次、人体质量指数(BMI)等一般临床资料比较，差异均无统计学意义(P>0.05)。本研究遵循的程序符合2013年新修订的《世界医学协会赫尔辛基宣言》要求。

①IBO组、IO组、对照组产妇使用球囊引产后，宫颈Bishop评分分别为(7.7±1.6)分、(8.1±1.5)分与(8.0±1.5)分，均较引产前的(3.1±0.5)分、(3.1±0.7)分与(3.2±0.6)分显著增加，并且差异均有统计学意义(t＝-31.883、-19.546、-37.544，P<0.001)。3组产妇放置球囊前、后宫颈Bishop评分，以及促宫颈成熟总有效率分别总体比较，差异均无统计学意义(P>0.05)。②IBO组、IO组、对照组产妇放置球囊时孕龄分别为39.7孕周(39.3～40.1孕周)、38.9孕周(37.8～39.7孕周)与40.4孕周(40.3～40.6孕周)，3组总体比较，差异有统计学意义(χ²＝157.093，P<0.001)，进一步两两比较结果显示，IBO组、IO组产妇放置球囊时孕龄均显著低于对照组，IBO组显著低于IO组，并且差异均有统计学意义(P<0.001、<0.001、＝0.006)。3组产妇分娩方式构成比比较，差异有统计学意义(χ²＝6.565，P＝0.038)，进一步两两比较结果显示，IO组中转急诊剖宫产术分娩率显著高于对照组，并且差异有统计学意义(28.9% vs 12.7%，χ²＝6.221，P＝0.013)。3组因发现胎心异常行急诊剖宫产术产妇所占比例比较，差异有统计学意义(χ²＝7.649，P＝0.022)，进一步两两比较结果显示，IO组显著高于对照组，并且差异有统计学意义(72.7% vs 22.7%，P＝0.003)。③3组产妇羊水胎粪污染发生率总体比较，差异有统计学意义(χ²＝11.368，P＝0.003)，进一步两两比较结果显示，IO组显著高于IBO组与对照组，并且差异均有统计学意义(23.7% vs 7.4%、6.9%，P＝0.008、0.005)。3组产妇产后发热发生率总体比较，差异有统计学意义(χ²＝8.109，P＝0.015)，进一步两两比较结果显示，IO组显著高于对照组，差异有统计学意义(P＝0.010)。3组产妇第一产程时长、球囊相关并发症发生率分别总体比较，差异均无统计学意义(P>0.05)。④3组产妇分娩新生儿的出生体重总体比较，差异有统计学意义(F＝7.677，P＝0.001)，进一步两两比较结果显示，IO组新生儿出生体重显著低于IBO组、对照组，并且差异均有统计学意义[(3 186.8±278.2) g vs(3 353.6±335.1) g、(3 405.3±301.1) g，P＝0.004、<0.001]。3组新生儿生后1 min Apgar评分、转入新生儿重症监护病房(NICU)所占比例分别总体比较，差异均无统计学意义(P>0.05)。

晚孕期IBO与IO可造成医源性早产，对该类足月妊娠产妇使用球囊引产，促进宫颈成熟效果明显，不增加相关并发症发生率及影响第一产程。

To explore effects of one-off single balloon cervical dilator (hereinafter referred as ballon) used for labor induction in full-term parturients with isolated borderline oligohydramnios (IBO) and isolated oligohydramnios (IO) and their pregnancy outcomes.

A total of 346 parturients who were hospitalized in Northern Jiangsu People′s Hospital from June 2018 to June 2020 with labor induction by balloon were selected as research subjects. According to amniotic fluid index (AFI) of parturients in the third trimester, they were divided into IBO group (n=135, 5 cm<AFI≤8 cm), IO group (n=38, AFI≤5 cm), and control group (n=173, parturients with normal AFI). The gestational age of placing balloon, Bishop scores before and after placement, effective rate of cervical maturation, vaginal delivery rate, rate of transition to emergency cesarean section, duration of the first labor, postpartum adverse pregnancy outcomes (amniotic fluid meconium contamination, postpartum fever, postpartum hemorrhage) and related complications of balloon, and newborn outcomes were observed and were compared by one-way ANOVA, Kruskal-Wallis H test, and chi-square test among three groups. Least significant difference (LSD)-t test and Bonferroni method for adjusting the significant level (α′=0.05/3=0.017) were used for further comparisons. There were no statistical differences in general clinical data among three groups, such as age, gravidity, body mass index (BMI), and so on (P>0.05). The procedure followed in this study complied with the requirements of the World Medical Association Declaration of Helsinki revised in 2013.

①After labor induction by balloon in IBO group, IO group, and control group, cervical Bishop scores were (7.7±1.6) scores, (8.1±1.5) scores and (8.0±1.5) scores respectively, which were significantly increased compared with those (3.1±0.5) scores, (3.1± 0.7) scores and (3.2±0.6) scores before labor induction, and all the differences were statistically significant (t=-31.883, -19.546, -37.544; P<0.001). There were no statistical differences in cervical Bishop scores before and after balloon placement, and total effective rate of promoting cervical ripening among three groups (P>0.05). ②The gestational ages of parturients in IBO group, IO group, and control group were 39.7 weeks (39.3-40.1 weeks), 38.9 weeks (37.8-39.7 weeks), and 40.4 weeks (40.3-40.6 weeks), respectively, and the difference was statistically significant (χ²=157.093, P<0.001). Further pairwise comparison results showed that the gestational ages of placing balloon of parturients in IBO group and IO group were significantly lower than that of control group, and IBO group was significantly lower than that in IO group, and all differences were statistically significant (P<0.001, <0.001, =0.006). There was statistical difference in constituent ratio of delivery methods among three groups (χ²=6.565, P=0.038), and further pairwise comparison results showed that the rate of emergency cesarean section in IO group was statistically higher than that of control group, and the difference was statistically significant (28.9% vs 12.7%, χ²=6.221, P=0.013). Comparison of the proportion of parturients undergoing emergency cesarean section due to abnormal fetal heart rate monitoring among three groups was statistically significant (χ²=7.649, P=0.022), and further pairwise comparison results showed that the rate of IO group was higher than that of control group, and the difference was statistically significant (72.7% vs 22.7%, P=0.003). ③There was statistically significant difference in the incidence of meconium contamination among three groups (χ²=11.368, P=0.003), and further pairwise comparison results showed that the incidence in IO group was statistically higher than those in IBO group and control group (23.7% vs 7.4% and 6.9%, P=0.008, 0.005). Comparison of the incidence of postpartum fever among three groups was statistically significant (χ²=8.109, P=0.015), and further pairwise comparison results showed that the incidence in IO group was statistically higher that in control group (P=0.010). There were no statistical differences in duration of the first labor and incidence of related complications of balloon among three groups (P>0.05). ④The comparison of birth weights of neonates among three groups was statistically significant (F=7.677, P=0.001), and further pairwise comparison results showed that birth weight of neonates in IO group was significantly lower than that of IBO group and control group [(3 186.8±278.2) g vs (3 353.6±335.1) g and (3 405.3±301.1) g, P=0.004, <0.001]. Apgar scores at 1 min after birth and proportion of neonates transferred to neonatal intensive care unit (NICU) among three groups showed no significant differences (P>0.05).

IBO and IO in the third trimester can lead to iatrogenic preterm birth. The use of balloon for labor induction can effectively promote cervical ripening without increasing the incidence of related complications of balloon and affecting the first stage of labor.