Labour · Induction
Membrane Sweep Likelihood
Probability of spontaneous labour within 48 h and 7 days after membrane sweep, by Bishop score, gestational age, and parity. NICE NG207 + Cochrane 2010.
Last reviewed 27 May 2026
Membrane sweep
Likelihood of spontaneous labour within 48 h / 7 days
Troubleshooting + common pitfalls
- Pitfall: Sweep at < 39 weeks.
Solution: Don’t. Sweep is offered at ≥ 39+0 (some units 38+0) for low-risk pregnancies. Earlier sweeps don’t change outcomes and may cause unnecessary discomfort. - Pitfall: Sweep with low-lying placenta / vasa praevia.
Solution: Confirm placental site (ideally normal 32-wk follow-up scan on file). Don’t sweep with known placenta praevia, vasa praevia, or unexplained APH. - Pitfall: Sweep with active genital herpes lesion.
Solution: Defer until lesions healed and post-aciclovir. - Pitfall: Sweep with ruptured membranes.
Solution: Contraindicated — infection risk. If SROM occurs at > 37 wk, manage per PROM pathway, not sweep. - Pitfall: Sweep with GBS positive without antibiotic plan.
Solution: No contraindication to sweep in GBS+ women, but ensure the labour-onset IAP pathway is in place (see /calculators/gbs-prophylaxis). - Pitfall: Sweep is interpreted as a quick guarantee.
Solution: Even at favourable Bishop, only ~25 % of women labour within 48 h. Counsel realistic expectations. - Pitfall: Bleeding after sweep mistaken for show vs APH.
Solution: Light spotting is common after sweep. Heavy bleeding, ongoing fresh red loss, or pain warrants urgent assessment. - Pitfall: No consent / not explaining discomfort.
Solution: Document informed consent including discomfort, bleeding, infection risk, possibility of accidental ROM, and lack of guarantee. Discomfort is the most common reason for declining a second sweep. - Pitfall: Repeated sweeps > 3 without escalation.
Solution: If three sweeps haven’t worked, move on to formal induction discussion rather than continuing weekly sweeps. - Pitfall: Sweep instead of treating reduced fetal movements.
Solution: RFM is a triage indication for CTG and possibly delivery, not a sweep indication. Don’t conflate the two pathways. - Pitfall: Sweep at the 41+ wk visit but not booking induction backup.
Solution: NICE NG207 recommends offering induction by 41+0–42+0 wk. Book the induction date at the sweep visit; cancel if sweep succeeds.
Educational tool only — not medical advice. NICE NG207; Cochrane 2010. Sweep decision and procedure by midwife / obstetric team.
What does this mean?
A membrane sweep (“stretch and sweep”) is a simple office procedure: the clinician sweeps a finger inside the cervix to mechanically separate the chorionic membranes from the lower uterine segment, releasing prostaglandins. NNT ~8 to avoid one formal induction in low-risk pregnancies at term (Cochrane 2010 meta-analysis of 22 RCTs, 2,797 women). Effect size depends heavily on Bishop score (favourable ≥ 6 doubles the 48-h labour rate) and gestational age (effect rises with each week past 40). Multiparous women labour earlier than nulliparous after any cervical intervention. Discomfort is the universal downside — well-counselled women tolerate the procedure fine, but lack of informed consent or unrealistic expectations (“baby’s coming tonight!”) drive most complaints. Three contraindications matter: low-lying placenta, ruptured membranes, active genital herpes. Sweep + induction backup is the practical pairing: offer the sweep at the 41+ wk visit; book induction for 41+0–42+0; cancel induction if spontaneous labour follows.
Introduction
A membrane sweep is a simple office procedure offered at term to reduce post-dates pregnancies and the need for formal induction. Cochrane 2010 NNT ~8 in low-risk pregnancies.
Eligibility window
- ≥ 39+0 weeks (some units 38+0) for low-risk pregnancies.
- Offered at routine 40- and 41-week visits.
- Pair with booked induction by 41+0–42+0 wk.
Contraindications
- Placenta praevia / low-lying placenta / vasa praevia
- Ruptured membranes
- Active genital herpes lesion
- Unexplained APH
Troubleshooting — common pitfalls
- Pitfall: Sweep < 39 weeks.
Solution: Don’t offer routinely. No outcome benefit, unnecessary discomfort. - Pitfall: Sweep with unknown placental site.
Solution: Confirm normal placenta on the third-trimester scan record. No sweep with praevia / vasa praevia. - Pitfall: Unrealistic expectations.
Solution: Counsel ~25 % maximum chance of labour within 48 h at the best Bishop / GA combination. - Pitfall: Heavy bleeding after sweep dismissed as “normal show”.
Solution: Light spotting yes; ongoing fresh red loss or pain → urgent assessment. - Pitfall: No induction backup booked.
Solution: NICE NG207 — book induction at 41+0–42+0 at the sweep visit; cancel if labour follows. - Pitfall: Sweep instead of triage for reduced fetal movements.
Solution: RFM → CTG and possibly delivery, not sweep. - Pitfall: Repeated sweeps > 3.
Solution: Move to formal induction rather than continuing weekly sweeps.
Sources
- NICE NG207. Inducing Labour. 2021, updated 2023.
- Boulvain M, Stan C, Irion O. Membrane sweeping for induction of labour. Cochrane Database Syst Rev 2005, updated 2010.
- de Miranda E, et al. Membrane sweeping and prevention of post-term pregnancy in low-risk pregnancies: a randomised controlled trial. BJOG 2006;113:402–8.
Frequently asked questions
What is a membrane sweep?
Also called 'stretch and sweep' — an office procedure where the clinician inserts a gloved finger through the cervix and sweeps it circumferentially to mechanically separate the chorionic membranes from the lower uterine segment. This releases local prostaglandins and increases the likelihood of spontaneous labour over the next 48 h to 7 days. Cochrane 2010 meta-analysis of 22 RCTs (2,797 women) showed NNT ~8 to avoid one formal induction.
When is sweep offered?
Per NICE NG207, sweep is offered at ≥ 39+0 weeks (some units from 38+0) for low-risk pregnancies, particularly at the 40- and 41-week routine visits. It's part of the 'expectant management with offered sweep' arm of the post-dates pathway, with formal induction by 41+0–42+0 if labour hasn't started.
How effective is it?
Effect varies with Bishop score and gestational age. At favourable Bishop ≥ 6 and 41 weeks, probability of labour within 48 h roughly doubles (~25 % vs ~10 % without sweep). At unfavourable Bishop or 39 weeks, the boost is smaller. Multiparous women labour faster than nulliparous after any cervical intervention.
What are the contraindications?
Absolute: placenta praevia / low-lying placenta (haemorrhage risk), vasa praevia, ruptured membranes (infection risk), active genital herpes lesion (transmission risk). Relative: unexplained APH, prior classical caesarean, severe maternal disease. GBS-positive women can have a sweep — ensure the IAP pathway is in place for labour onset.
Does it hurt?
Most women describe the procedure as uncomfortable to painful for the ~30–60 seconds of the sweep itself. Cramping for a few hours afterwards is common. Light pink spotting is also common and not concerning. Heavy bleeding, ongoing fresh red loss, severe pain, or fluid leak warrants urgent assessment.
Does it cause infection?
Cochrane 2010 showed no increase in infection rates compared with no sweep. Care with sterile technique is standard. Sweep is contraindicated with already-ruptured membranes specifically because of ascending infection risk.
How many sweeps?
Up to 3 sweeps offered at intervals of a few days. Beyond that, escalate to formal induction discussion. Multiple sweeps offer modest incremental benefit but diminishing returns; persistent failure to enter labour at 41+ wk warrants the induction pathway rather than more sweeps.
How does this relate to other calculators on BumpBites?
Companion: /calculators/bishop-score for cervical favourability assessment; /calculators/oxytocin-titration for the formal induction pathway if sweep fails; /calculators/gbs-prophylaxis for IAP context in GBS+ women; /calculators/friedman-labor for labour-progress thresholds once labour begins; /calculators/due-date for gestational dating that drives offer timing.