产程中会阴体伸展不能预测不良转归

亚利桑那州斯科茨代尔——最新数据显示，在第二产程中的会阴体伸展程度无助于预测哪些产妇将发生不良妇产科转归。

新墨西哥大学妇产科的Jill Alldredge博士在产外科医师协会（SGS）年会上指出，已知会阴体长度较短会增加分娩时重度会阴撕裂以及产后功能障碍的风险。产妇在第二产程中用力娩出胎儿而伸展盆底时也可能损伤盆底肌肉。

Alldredge博士及其同事按照预定计划对APPLE cohort（妊娠、分娩及之后的盆底变化）进行了二次分析，涉及448例在有资质的助产士协助下尝试引导分娩的初产女性。这些女性之后再次接受会阴检测，并且接受前瞻性随访至产后12个月。

Jill Alldredge博士

结果显示，第二产程中的会阴体最大长度与产前相比增加约2.4 cm。产前会阴体平均长度为3.7 cm，第二产程中会阴体平均最大长度为6.1 cm。在第二产程中，肛门的最大径平均为2.0 cm。生殖道裂孔的前后最大径为7.5 cm，最大横径为4.7 cm，最大阴道前庭面积为119.4 cm²。APPLE研究的受试者在产前、产程发动时、第二产程发动时、第二产程中每10分钟，以及产后6和12个月时接受会阴体长度测量。在第二产程中还测量了肛门和生殖道裂孔。产后6个月时，这些女性完成了一系列用于评估盆底功能的问卷：失禁严重度指数、Wexner排便失禁量表和女性性功能指数。

总共有35%的女性发生了2级或更严重的会阴撕裂。产后6个月时，72%的产妇有至少为轻度的尿失禁，68%有至少为轻度的排便失禁，13%不处于性活跃状态。

然而，不论是会阴体长度还是任何时间点的会阴体长度，均与会阴撕裂、尿道或肛门失禁、产后6个月时性生活不活跃等无关。

Alldredge博士评论称：“我们可以看到，会阴是动态变化的，在产程中的确会伸展。但是，检测会阴体长度和产前、产时及产后的会阴体长度变化并不能预测会阴撕裂或产后盆底功能障碍。”

Alldredge博士报告称无相关利益冲突。

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By: SUSAN LONDON, Ob.Gyn. News Digital Network

SCOTTSDALE, ARIZ. – The extent of stretching of the perineal body during the second stage of labor is not helpful in predicting which women will experience adverse obstetric and postpartum outcomes, new data show.

Short perineal body length is known to increase the risk of severe perineal laceration at the time of delivery as well as postpartum functional disorders, noted presenting author Dr. Jill Alldredge. Maternal expulsive efforts during the second stage of labor that stretch the pelvic floor may also damage the pelvic floor muscles.

She and her colleagues performed a planned secondary analysis of the APPLE cohort (Alterations in the Pelvic Floor in Pregnancy, Labor and Ensuing Years), analyzing data from 448 nulliparous women who had a vaginal birth attended by a certified nurse-midwife, had repeated perineal measurements over time, and were followed prospectively to 12 months post partum.

On average, perineal body length increased by about 2.4 cm in the cohort between the antepartum period and the maximal length during the second stage of labor, according to data reported at the annual scientific meeting of the Society of Gynecologic Surgeons.

However, neither perineal body length nor change in this length at any time point was associated with perineal lacerations, or with urinary or anal incontinence or not being sexually active at 6 months post partum.

"We can see that the perineum is dynamic and does stretch during labor. However, measurement of the perineal body length and change in perineal body length between the antepartum, intrapartum, and post partum time periods does not predict perineal trauma or postpartum pelvic floor dysfunction," commented Dr. Alldredge, an obstetrics-gynecology resident at the University of New Mexico in Albuquerque.

APPLE participants had measurement of the perineal body length during the antepartum period, at the onset of labor, at the onset of and every 10 minutes during the second stage, and at 6 and 12 months post partum. The anal opening and the genital hiatus also were measured during the second stage of labor.

At 6 months, the women completed a set of questionnaires assessing pelvic floor function: the Incontinence Severity Index, theWexner Fecal Incontinence Scale, and the Female Sexual Function Index.

The mean perineal body length was 3.7 cm during the antepartum period, and the mean maximal perineal body length during the second stage of labor was 6.1 cm, she said at the meeting, jointly sponsored by the American College of Surgeons.

During the second stage of labor, the maximal anal opening was 2.0 cm on average. The genital hiatus had an anterior-posterior maximal diameter of 7.5 cm, a maximal transverse diameter of 4.7 cm, and a maximal introital area of 119.4 cm2.

Overall, 35% of women experienced a second-degree or worse perineal tear. And at 6 months post partum, 72% had at least mild urinary incontinence, 68% had at least mild anal incontinence, and 13% were not sexually active.

However, analyses showed that neither perineal body length nor stretch at any of the time points assessed was significantly associated with any of these outcomes.

Dr. Alldredge disclosed no relevant conflicts of interest.