探讨不同分娩方式产妇2次分娩间隔时间与产后盆底功能指标的关系。

选择2022年1月至2023年12月于上海市第一妇婴保健院分娩的345例产妇为研究对象。采用回顾性分析方法，根据2次分娩方式不同，将其分为剖宫产术分娩组(n＝152)和自然分娩组(n＝193)。所有产妇均于第2次分娩后第45~60天接受盆底肌功能及盆底结构检测，并采用《盆底功能障碍症状调查简表》(PFDI-20)评估盆底功能障碍(PFD)相关症状。对2组产妇按照2次分娩间隔时间<3年、3~10年和>10年3个时间段进行分层，剖宫产术分娩组中，2次分娩间隔时间<3年、3~10年、>10年者分别为35、63、54例；自然分娩组中，2次分娩间隔时间<3年、3~10年、>10年者分别为56、88、49例。比较2组产妇与3个时间段进行分层产妇的Ⅰ类肌纤维平均肌电值及变异性、Ⅱ类肌纤维最大肌电值及上升时间、盆膈裂孔周长和面积、PFDI-20评分差异，并采用Spearman秩相关检验，分析2次分娩不同分娩间隔时间与产后盆底功能指标的相关性。本研究遵循的程序符合上海市第一妇婴保健院伦理委员会制定的标准，并获得该伦理委员会批准(审批文号：20220109)。

本研究结果如下。①剖宫产术分娩组与自然分娩组产妇年龄、2次分娩间隔时间、人体质量指数(BMI)、2次分娩新生儿出生体重及分娩胎龄比较，差异均无统计学意义(P>0.05)。②剖宫产术分娩组产妇Ⅰ类肌纤维平均肌电值和Ⅱ类肌纤维最大肌电值，均高于自然分娩组，Ⅰ类肌纤维(慢肌纤维，负责耐力)变异性和Ⅱ类肌纤维(快肌纤维，负责爆发力)的上升时间，则均低于自然分娩组，差异均有统计学意义(P<0.05)；而自然分娩组产妇盆膈裂孔周长和面积，均大于剖宫产术分娩组，PFDI-20各分量表评分及总分，则均高于剖宫产术分娩组，并且差异均有统计学意义(P<0.05)。③根据2次分娩时间间隔不同，剖宫产术分娩组和自然分娩组产妇组内间盆底肌肌电指标、盆底结构指标及PFDI-20评分比较，差异亦均有统计学意义(P<0.05)；并且2次分娩间隔为3~10年者的相关盆底功能指标相对较好，而2次分娩间隔<3年者，则相关盆底功能指标相对较差。④相关性分析结果显示，按2次分娩间隔时间分层时，在<3年和3~10年时间段内，剖宫产术分娩组和自然分娩组产妇Ⅰ类肌纤维平均肌电值、Ⅱ类肌纤维最大肌电值均与具体分娩间隔时间呈正相关(P<0.05)；其余盆底功能指标与具体分娩间隔时间均无相关性(P>0.05)。

分娩方式及2次分娩间隔时间，可能与产妇产后盆底功能恢复有关。与自然分娩相比，剖宫产术分娩产妇的产后盆底功能指标总体较好；2次分娩间隔3~10年者的相关盆底功能指标相对较优。临床应重视对自然分娩及再次妊娠间隔较短产妇的产后盆底功能筛查和康复指导。

To investigate the relationship between the interval between two deliveries and postpartum pelvic floor function indicators in women with different modes of delivery.

A total of 345 women who delivered at Shanghai First Maternity and Infant Hospital from January 2022 to December 2023 were enrolled in this retrospective study. According to the modes of the two deliveries, the women were divided into the cesarean delivery group (n=152) and the natural childbirth group (n=193). Based on the interval between the two deliveries, women in both groups were stratified into three categories: <3 years, 3-10 years, and >10 years. All participants underwent pelvic floor muscle function and pelvic floor structure examinations at 45-60 days after the second delivery. Postpartum pelvic floor dysfunction-related symptoms were assessed using the Pelvic Floor Distress Inventory-20 (PFDI-20). The differences in type Ⅰ muscle fiber mean electromyographic value and variability, type Ⅱ muscle fiber maximum electromyographic value and rise time, levator hiatus circumference and area, and PFDI-20 scores were compared between the two groups at different delivery intervals. Spearman rank correlation analysis was performed to evaluate the correlation between the interval between two deliveries and postpartum pelvic floor function indicators. The procedures of this study complied with the standards established by the Ethics Committee of Shanghai First Maternity and Infant Hospital, and the study was approved by the ethics committee (Approval No.20220109).

① There were no statistically significant differences between the cesarean delivery group and the natural childbirth group in maternal age, interval between two deliveries, body mass index, neonatal birth weight at the first and current deliveries, or gestational age at the first and current deliveries (P>0.05). ② At different delivery intervals, the type Ⅰ muscle fiber mean electromyographic value and type Ⅱ muscle fiber maximum electromyographic value in the cesarean delivery group were generally higher than those in the natural childbirth group, whereas the type Ⅰ muscle fiber variability and type Ⅱ muscle fiber rise time were generally lower than those in the natural childbirth group; these differences were statistically significant (P<0.05). The levator hiatus circumference and area in the natural childbirth group were greater than those in the cesarean delivery group, and the PFDI-20 subscale scores and total score were higher than those in the cesarean delivery group, with statistically significant differences (P<0.05). ③ In both the cesarean delivery group and the natural childbirth group, pelvic floor muscle electromyographic indicators, pelvic floor structure indicators, and PFDI-20 scores differed significantly among women with different delivery intervals (P<0.05). Overall, women with an interval of 3-10 years between the two deliveries had relatively better pelvic floor function indicators, whereas those with an interval of <3 years had relatively poorer pelvic floor function indicators. ④ Correlation analysis showed that, among women with delivery intervals of <3 years and 3-10 years, the type Ⅰ muscle fiber mean electromyographic value and type Ⅱ muscle fiber maximum electromyographic value were positively correlated with the specific delivery interval in both the cesarean delivery group and the natural childbirth group (P<0.05), whereas no correlation was observed for the other indicators (P>0.05).

Mode of delivery and the interval between two deliveries may be associated with postpartum pelvic floor function recovery. Compared with women who underwent natural childbirth, those who underwent cesarean delivery had generally better postpartum pelvic floor function indicators. Women with an interval of 3-10 years between two deliveries had relatively better pelvic floor function indicators. Clinical attention should be paid to postpartum pelvic floor function screening and rehabilitation guidance for women who undergo natural childbirth and those with a short interval before a subsequent pregnancy.