Last updated on March 2019

Lateral Episiotomy or Not in Vacuum Assisted Delivery in Non-parous Women


Brief description of study

Non-parous women with a live singleton pregnancy in cephalic presentation past 34 gestational weeks will be randomized to lateral episiotomy or no episiotomy when operative vaginal delivery by vacuum extraction is indicated. Primary outcome is clinically diagnosed obstetric anal sphincter injury (OASIS) of any degree.

Detailed Study Description

The study has started at Danderyd Hospital. Danderyd Hospital is a large teaching hospital affiliated to the Karolinska Institute in Stockholm, Sweden. Danderyd Hospital attends approximately 7 000 deliveries annually, of which 330 are vacuum extractions in non-parous women. Other hospitals in Stockholm County and other parts of Sweden are invited to participate in the study.

Informed consent is collected from non-parous women with a singelton, live fetus in cephalic presentation, with a planned vaginal delivery and without previous gynecological surgery due to incontinence or prolapse. Women can be approached at any time from gestational week 25 until delivery, unless they are in severe pain or discomfort, there is not enough time to consider the information, or there is a language barrier. The informed consent form is kept at the receiving research department and a note of consent/no consent is made in the obstetrical medical file, which pops up every time the file is opened.

At indication for vacuum extraction, the patient's consent is confirmed verbally and allocation is made by opaque envelopes on the vacuum extraction equipment mobile cart. Randomization is performed 1:1 in blocks of 4 by an external organization (Karolinska Trial Alliance).

Lateral episiotomy is performed according to the intervention description. Total sample size has been calculated to 1400 women, if a reduction in OASIS prevalence from today's 12.2% to 7.7% in operative vaginal deliveries is to be detected (estimated drop-out rate 3% for the primary outcome). The women will be recruited over a maximum of 3 years. An interim analysis will be performed after 350 randomized women to each arm, since a 50% reduction to less than 6.1% sphincter tears could be detected with less than 5% risk of a type-1 error at this sample size. If such a reduction is seen, the study will be closed.

Data is collected prospectively through Case Record Forms and the obstetrical medical file Obstetrix (Cerner Sverige AB), which covers approximately 98% of deliveries with complete data, and the Swedish Pregnancy Register covering the whole of Sweden from 2015 as well as the (optional) Swedish Obstetrical Tear Register, which Danderyd Hospital is a part of since 2014. From the Obstetrical Tear Register, questionnaires are sent out in paper form or electronically to patients with a diagnosed anal sphincter tear at delivery, 8 weeks and 12 months after delivery. The same questionnaires is sent out electronically in the follow-up of the study participants regardless of randomization or result (sphincter tear or not). In addition, the participants will be sent questionnaires regarding birth satisfaction (BSS-R and CEQ 2.0) at 8 weeks after delivery and questionnaires regarding sexual function (FSFI and FSDS) and quality of life (Euro-QoL-5D) at delivery and after 12 months.

A follow-up from registers regarding mode of delivery and prevalence of episiotomy and OASIS in subsequent births will be performed at 2 years, 5 years, and 10 years after the index birth.

Clinical Study Identifier: NCT02643108

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