What is the question?
The aim of this Cochrane Review is to find out if membrane sweeping is a safe and effective way of inducing labour at or near term and if it is more effective than the formal methods of induction.
Why is this important?
Most commonly, formal induction of labour is offered to women when continuing with a pregnancy is considered probably more harmful for the mother or baby than the adverse effects of induction. The most common reason for formal induction of labour is post-term pregnancy (pregnancies that continue past 42 weeks' gestation).
Membrane sweeping is a relatively simple, low-cost procedure that seeks to reduce the use of formal induction of labour and it can be performed without the need for hospitalisation. It involves the clinician inserting one or two fingers into the lower part of the uterus (the cervix) and using a continuous circular sweeping motion to free the membrane from the lower uterus. Formal induction of labour involves artificially stimulating the uterus with drugs such as prostaglandins or oxytocin or by breaking the amniotic sack that holds the baby (breaking the waters).
What evidence did we find?
We searched for evidence on 25 February 2019. We included 44 randomised studies that reported findings for 6940 women from a wide range of countries including high-, middle- and low-income countries.
Studies compared membrane sweeping with no intervention or sham intervention, and also compared membrane sweeping with vaginal or intracervical prostaglandins, oral misoprostol, oxytocin and repeated membrane sweeping.
Of the seven studies that reported financial funding, two studies reported funding from pharmaceutical companies. Overall, the certainty of the evidence was found to be low.
Key results
Compared with no intervention or a sham sweep (40 studies involving 6548 women), allocated to membrane sweeping may be more likely to have spontaneous onset of labour, but we found no clear difference in unassisted vaginal births. Women may also be less likely to have formal induction of labour. We also found no clear differences between the groups for caesarean section, instrumental vaginal births or serious illness or death of the mother or baby.
Compared with vaginal or intracervical prostaglandins (four studies involving 480 women), we found no difference in any outcomes although data were limited.
We found insufficient data to draw any conclusions in the studies comparing membrane sweep with intravenous oxytocin, with or without breaking the waters, or with vaginal/oral misoprostol. Similarly for the comparison between different frequencies of membrane sweeping.
What does this mean?
Membrane sweeping appears to be effective in promoting labour but current evidence suggests this did not, overall, follow-on to unassisted vaginal births. Membrane sweeping may reduce formal induction of labour. Only three studies reported on women’s satisfaction with membrane sweeping. Women reported feeling positive about membrane sweeping. While acknowledging that it may be uncomfortable, they felt the benefits outweighed the harms and most would recommend it to other women. Further research is needed to confirm our review findings and to identify the ideal time for membrane sweep and whether having more than one sweep would be beneficial. Further information on women’s views is also needed.
Membrane sweeping may be effective in achieving a spontaneous onset of labour, but the evidence for this was of low certainty. When compared to expectant management, it potentially reduces the incidence of formal induction of labour. Questions remain as to whether there is an optimal number of membrane sweeps and timings and gestation of these to facilitate induction of labour.
Induction of labour involves stimulating uterine contractions artificially to promote the onset of labour. There are several pharmacological, surgical and mechanical methods used to induce labour. Membrane sweeping is a mechanical technique whereby a clinician inserts one or two fingers into the cervix and using a continuous circular sweeping motion detaches the inferior pole of the membranes from the lower uterine segment. This produces hormones that encourage effacement and dilatation potentially promoting labour. This review is an update to a review first published in 2005.
To assess the effects and safety of membrane sweeping for induction of labour in women at or near term (≥ 36 weeks' gestation).
We searched Cochrane Pregnancy and Childbirth’s Trials Register (25 February 2019), ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (25 February 2019), and reference lists of retrieved studies.
Randomised and quasi-randomised controlled trials comparing membrane sweeping used for third trimester cervical ripening or labour induction with placebo/no treatment or other methods listed on a predefined list of labour induction methods. Cluster-randomised trials were eligible, but none were identified.
Two review authors independently assessed studies for inclusion, risk of bias and extracted data. Data were checked for accuracy. Disagreements were resolved by discussion, or by including a third review author. The certainty of the evidence was assessed using the GRADE approach.
We included 44 studies (20 new to this update), reporting data for 6940 women and their infants. We used random-effects throughout.
Overall, the risk of bias was assessed as low or unclear risk in most domains across studies. Evidence certainty, assessed using GRADE, was found to be generally low, mainly due to study design, inconsistency and imprecision. Six studies (n = 1284) compared membrane sweeping with more than one intervention and were thus included in more than one comparison.
No trials reported on the outcomes uterine hyperstimulation with/without fetal heart rate (FHR) change, uterine rupture or neonatal encephalopathy.
Forty studies (6548 participants) compared membrane sweeping with no treatment/sham
Women randomised to membrane sweeping may be more likely to experience:
· spontaneous onset of labour (average risk ratio (aRR) 1.21, 95% confidence interval (CI) 1.08 to 1.34, 17 studies, 3170 participants, low-certainty evidence).
but less likely to experience:
· induction (aRR 0.73, 95% CI 0.56 to 0.94, 16 studies, 3224 participants, low-certainty evidence);
There may be little to no difference between groups for:
· caesareans (aRR 0.94, 95% CI 0.85 to 1.04, 32 studies, 5499 participants, moderate-certainty evidence);
· spontaneous vaginal birth (aRR 1.03, 95% CI 0.99 to 1.07, 26 studies, 4538 participants, moderate-certainty evidence);
· maternal death or serious morbidity (aRR 0.83, 95% CI 0.57 to 1.20, 17 studies, 2749 participants, low-certainty evidence);
· neonatal perinatal death or serious morbidity (aRR 0.83, 95% CI 0.59 to 1.17, 18 studies, 3696 participants, low-certainty evidence).
Four studies reported data for 480 women comparing membrane sweeping with vaginal/intracervical prostaglandins
There may be little to no difference between groups for the outcomes:
· spontaneous onset of labour (aRR, 1.24, 95% CI 0.98 to 1.57, 3 studies, 339 participants, low-certainty evidence);
· induction (aRR 0.90, 95% CI 0.56 to 1.45, 2 studies, 157 participants, low-certainty evidence);
· caesarean (aRR 0.69, 95% CI 0.44 to 1.09, 3 studies, 339 participants, low-certainty evidence);
· spontaneous vaginal birth (aRR 1.12, 95% CI 0.95 to 1.32, 2 studies, 252 participants, low-certainty evidence);
· maternal death or serious morbidity (aRR 0.93, 95% CI 0.27 to 3.21, 1 study, 87 participants, low-certainty evidence);
· neonatal perinatal death or serious morbidity (aRR 0.40, 95% CI 0.12 to 1.33, 2 studies, 269 participants, low-certainty evidence).
One study, reported data for 104 women, comparing membrane sweeping with intravenous oxytocin +/- amniotomy
There may be little to no difference between groups for:
· spontaneous onset of labour (aRR 1.32, 95% CI 88 to 1.96, 1 study, 69 participants, low-certainty evidence);
· induction (aRR 0.51, 95% CI 0.05 to 5.42, 1 study, 69 participants, low-certainty evidence);
· caesarean (aRR 0.69, 95% CI 0.12 to 3.85, 1 study, 69 participants, low-certainty evidence);
· maternal death or serious morbidity was reported on, but there were no events.
Two studies providing data for 160 women compared membrane sweeping with vaginal/oral misoprostol
There may be little to no difference between groups for:
· caesareans (RR 0.82, 95% CI 0.31 to 2.17, 1 study, 96 participants, low-certainty evidence).
One study providing data for 355 women which compared once weekly membrane sweep with twice-weekly membrane sweep and a sham procedure
There may be little to no difference between groups for:
· induction (RR 1.19, 95% CI 0.76 to 1.85, 1 study, 234 participants, low-certainty);
· caesareans (RR 0.93, 95% CI 0.60 to 1.46, 1 study, 234 participants, low-certainty evidence);
· spontaneous vaginal birth (RR 1.00, 95% CI 0.86 to 1.17, 1 study, 234 participants, moderate-certainty evidence);
· maternal death or serious maternal morbidity (RR 0.78, 95% CI 0.30 to 2.02, 1 study, 234 participants, low-certainty evidence);
· neonatal death or serious neonatal perinatal morbidity (RR 2.00, 95% CI 0.18 to 21.76, 1 study, 234 participants, low-certainty evidence);
We found no studies that compared membrane sweeping with amniotomy only or mechanical methods.
Three studies, providing data for 675 women, reported that women indicated favourably on their experience of membrane sweeping with one study reporting that 88% (n = 312) of women questioned in the postnatal period would choose membrane sweeping in the next pregnancy.
Two studies reporting data for 290 women reported that membrane sweeping is more cost-effective than using prostaglandins, although more research should be undertaken in this area.