产后腹直肌分离高频超声特征及其与分娩方式的关系

The high frequency ultrasonographic features of rectus diastasis and their relationships with the modes of delivery in postpartum women

目的探讨产后早期女性腹直肌分离(RD)的多位点高频超声特征及其与不同分娩方式的关系。方法收集2020年3-5月于浙江大学医学院附属妇产科医院分娩并进行产后6周检查的初产妇571例,按分娩方式分为阴道分娩组(336例)和剖宫产组(235例),采用高频超声检查,测量静息状态5个位点(脐上4.5 cm、脐上3 cm、脐上缘、脐下缘、脐下3 cm)和屈曲状态2个位点(脐上缘、脐下缘)的腹直肌间距(IRD)及两种状态右侧平脐腹直肌厚度。分析两种分娩方式对各位点IRD的影响及两种状态下IRD的变化,采用Spearman相关性分析评估腹直肌厚度与各位点IRD间的相关性。结果产后早期RD发生率为79.7%(455/571),以脐上3 cm和脐周为著。静息状态下,阴道分娩组5个位点IRD分别为(1.62±0.79)cm、(2.03±0.84)cm、(2.65±0.94)cm、(2.09±0.93)cm、0.54(0.00,1.13)cm,剖宫产组5个位点IRD分别为(1.75±0.85)cm、(2.26±0.99)cm、(2.99±1.14)cm、(2.57±1.21)cm、1.00(0.41,1.59)cm,两组间差异有统计学意义(均P<0.05)。屈曲状态下,阴道分娩组2个位点IRD分别为(2.10±0.84)cm、(1.66±0.86)cm,剖宫产组2个位点IRD分别为(2.28±0.87)cm、(1.91±0.87)cm,两组间差异有统计学意义(均P<0.05)。屈曲状态较静息状态,阴道分娩组在脐上缘和脐下缘IRD增大的发生率分别为16.1%和26.5%;剖宫产组在脐上缘和脐下缘IRD增大的发生率分别为17.4%和20.4%。静息状态和屈曲状态下,阴道分娩组与剖宫产组腹直肌厚度差异有统计学意义[(0.74±0.12)cm对(0.67±0.12)cm,P<0.05;(1.11±0.23)cm对(0.99±0.22)cm,P<0.05)]。静息状态下,腹直肌厚度与5个位点IRD呈负相关(rs=-0.116、-0.140、-0.185、-0.143、-0.144,均P<0.01)。屈曲状态下,腹直肌厚度与脐上缘IRD呈负相关(rs=-0.091,P<0.05),与脐下缘IRD无明显相关性(P>0.05)。结论高频超声可以评估多位点不同状态产后腹直肌形态学特征,剖宫产相比阴道分娩后腹直肌厚度较薄、IRD较大,但受屈曲状态影响较小。

Objective To investigate the multi-sites high frequency ultrasound features of rectus diastasis (RD) in early postpartum women and their relationships with different delivery modes.Methods Total of 571 primiparas who gave birth in the Obstetrics and Gynecology Hospital Affiliated to Zhejiang University Medical College from March to May 2020 and underwent 6-week postpartum examination were chosen, they were divided into vaginal delivery group (336 cases) and the cesarean section group (235 cases). The inter-rectus distance(IRD) of five loci (umbilical on 4.5 cm, umbilical on 3 cm, umbilical edge, edge of umbilical, umbilical down 3 cm) at resting state and two loci (umbilical edge, edge of umbilical) at curling state as well as the rectus thickness on the right side of umbilical level were observed by high frequency ultrasound. The impacts of the two delivery modes on IRD at each site and the changes of IRD under the two conditions were analyzed. Spearman correlation analysis was used to evaluate the correlation between the thickness of rectus abdominis and IRD at each site.Results The incidence of early postpartum RD was 79.7% (455/571), most of which occurring at 3 cm above the umbilicus and the umbilicus levels. At resting state, the IRDs at the 5 loci of vaginal delivery group were (1.62±0.79)cm, (2.03±0.84)cm, (2.65±0.94)cm, (2.09±0.93)cm, and 0.54(0.00, 1.13)cm respectively, while the IRDs at 5 loci of the cesarean section group were (1.75±0.85)cm, (2.26±0.99)cm, (2.99±1.14)cm, (2.57±1.21)cm, and 1.00(0.41, 1.59)cm, with statistical differences at all the levels between groups (P<0.05). Under the curling state, the IRDs at the 2 loci of vaginal delivery group were (2.10±0.84)cm and (1.66±0.86)cm respectively, while the IRDs at the 2 loci of cesarean section group were (2.28±0.87)cm and (1.91±0.87)cm, with statistical differences between groups(P<0.05). The incidences of increased IRD when compared between resting and curling states at the upper and lower umbilicus in the vaginal delivery group were 16.1% and 26.5%, with 17.4% and 20.4% in the cesarean section group. At the resting state, there was a significant difference in the thickness of rectus abdominis between the vaginal delivery and cesarean section groups [(0.74±0.12)cm vs (0.67±0.12)cm, P<0.05]. At the curling state, the difference between two groups was statistically significant [(1.11±0.23)cm vs (0.99±0.22)cm, P<0.05]. The thickness of rectus abdominis was negatively correlated with IRD(all the 5 loci at resting state, rs=-0.116, -0.140, -0.185, -0.143, -0.144, all P<0.01;and the upper umbilical loci at curling state, rs=-0.091, P<0.05). There was no significant correlation between the thickness of rectus abdominis and IRD at the lower umbilical edge at the curling state (P>0.05).Conclusions High frequency ultrasound can evaluate the morphological characteristics of the abdominal rectus muscle in early postpartum stage. Compared with vaginal delivery, rectus abdominis thickness, the IRD is larger in cesarean section primiparas, but less affected by the curling state.