Inducing labour
If your waters break before 34 weeks, you’ll only be offered induction if there are other factors that suggest it’s the best thing for you and your baby.
Membrane Sweep At 39 Weeks Success Rate
Study Population: Patients who are pregnant with a live fetus at or near term (36 weeks or greater estimated gestational age) without indication for induction or urgent delivery
Efficacy End Points: Primary: spontaneous onset of labor, need for induction of labor, need for cesarean delivery, spontaneous vaginal delivery; secondary: instrument-assisted vaginal birth, epidural analgesia
Harm End Points: Primary: maternal death or serious morbidity, uterine hyperstimulation with or without fetal heart rate deceleration, neonatal death, serious perinatal morbidity; secondary: postpartum hemorrhage, uterine rupture, augmentation of labor
Narrative: Approximately 20% to 25% of deliveries occur after labor induction in middle-to high-income countries. 1 Membrane sweeping is a common outpatient intervention associated with cervical dilatation assessment. Membrane sweeping is the advancement of one or two fingers through the internal cervical os to the lower uterine segment, followed by a circular sweeping movement between the amniotic membrane and the lower uterine segment. Successful performance of this procedure can decrease the need for formal induction with pharmacologic or mechanical methods or the need for hospitalization or advanced monitoring. The process of membrane sweeping leads to the release of phospholipase A2 and prostaglandin F2α, which directly contribute to cervical ripening through an inflammatory cascade. 2
| Green | Benefits greater than harms |
| Yellow | Unclear benefits |
| Red | No benefits |
| Black | Harms greater than benefits |
A 2020 Cochrane review included 44 studies and 6,940 patients in 19 countries (14 from the United States). 2 The trials compared membrane sweeping with expectant management, sham membrane sweeps, and several induction methods, including vaginal and intracervical prostaglandins and intravenous oxytocin (Pitocin). Seventeen randomized controlled trials (RCTs) with 3,170 patients compared membrane sweeping with expectant management, demonstrating a relative risk of 1.21 (95% CI, 1.08 to 1.34), an absolute risk difference of 12.5%, and a number needed to treat of 8 for spontaneous onset of labor. Sixteen RCTs with 3,224 patients demonstrated a relative risk of 0.73 (95% CI, 0.56 to 0.94) for requiring labor induction. This corresponds to an absolute risk reduction of 8.5% and a number needed to treat of 12 to prevent the need for further mechanical or pharmacologic induction of labor. Other primary outcomes, including the likelihood of spontaneous vaginal delivery, were not significantly different.
Evidence certainty was low to moderate for all primary outcomes. Patient perception of membrane sweeping was positive. In one study in the Netherlands (n = 742), 88% of patients noted they would opt for membrane sweeping in subsequent pregnancies if it were offered; 31% characterized the procedure as not painful, 51% as somewhat painful, and 17% as painful or very painful. Even among those who had pain, 88% indicated they would opt for the procedure again. 3
Caveats: Despite the good numbers needed to treat and large sample sizes, the studies included in the Cochrane review had low certainty of evidence as assessed using the GRADE approach. The authors performed sensitivity analyses and excluded studies at high or unclear risk of bias for sequence generation or allocation concealment and studies with high or unclear risk of attrition. When sensitivity analyses were performed, including 12 of the 40 identified trials with low risk of bias, the result for spontaneous onset of labor was no longer statistically significant. Moderate heterogeneity was present in these included trials (Tau 2 = 0.00; I 2 = 37%; P = .16).
This Cochrane review predates the ARRIVE trial, which examined the safety of induction vs. expectant management at 39 weeks’ estimated gestational age. The results of ARRIVE are expected to increase the overall percentage of induced deliveries. 4 – 7 Therefore, a safe, evidence-based modality such as membrane sweeping, which minimizes the need for formal induction, could have strong clinical utility.
The Cochrane review included data from 19 countries, a breadth of resource settings, and urban and rural locations. There was significant procedural heterogeneity across studies in the number of revolutions and standard depth of digital advancement in the membrane sweeping procedure. Sweeps can also be associated with bleeding from undiagnosed placenta previa or a low-lying placenta, which were not reported in this review because they were exclusion criteria.
There are concerns about the safety of membrane sweeping in carriers of group B streptococci. A prospective trial of 542 patients who underwent membrane sweeping demonstrated a nonsignificant difference in all study outcomes between those who were positive for group B streptococci and those who were negative. 8
This Cochrane review did not address the possibility of artificial rupture of membranes after membrane sweeping. In one RCT of 300 patients, there was no significant difference in rates of prelabor rupture of membranes when directly comparing those who underwent membrane sweeping with those who did not. In subgroup analyses, patients with cervical dilatation of 1 cm or greater had a relative risk of 1.10 (95% CI, 1.03 to 1.18), with a number needed to harm of 378 for prelabor rupture of membranes. 9 Studies comparing membrane sweeping with amniotomy and oxytocin demonstrated no statistically significant differences in outcomes or safety across the study groups. The same was true of one-time membrane sweeping vs. recurrent membrane sweeping. 2
Conclusion: The American College of Obstetricians and Gynecologists mentions membrane sweeping in their practice bulletin on induction of labor without an overt endorsement. 10 The 2021 guidelines from the National Institute for Health and Care Excellence state that membrane sweeping should be offered at 39 weeks’ gestation and during subsequent antenatal visits if labor does not spontaneously commence. 11 The Society of Obstetricians and Gynaecologists of Canada mentions membrane sweeping in its guidelines but does not include it as part of the evidence-based recommendations. 12 The World Health Organization recommendations on labor induction at or beyond term detail most induction modalities but do not explicitly mention membrane sweeping. 1
A lack of trial data precludes the development of a clear consensus on the ideal timing and frequency of membrane sweeping. A color recommendation of yellow (unclear benefits) was assigned to this intervention because of uncertainties and the low quality of evidence generated by the trials included in the systematic review.
The views expressed are those of the authors and do not necessarily reflect the official policy or position of the Department of the Navy, Uniformed Services University of the Health Sciences, Navy Medicine and Readiness Training Command Camp Pendleton, the Department of Defense, or the U.S. government.
Copyright ©2024 MD Aware, LLC (theNNT.com). Used with permission.
This series is coordinated by Christopher W. Bunt, MD, AFP assistant medical editor, and the NNT Group.
Inducing labour
An induced labour is one that’s started artificially.
It’s common for labour to be induced if your baby is overdue or there’s any risk to you or your baby’s health.
This risk could be if you have a health condition such as high blood pressure, for example, or your baby is not growing.
Induction will usually be planned in advance. You’ll be able to discuss the advantages and disadvantages with your doctor and midwife, and find out why they think your labour should be induced.
It’s your choice whether to have your labour induced or not.
If your pregnancy lasts longer than 42 weeks and you decide not to have your labour induced, you should be offered increased monitoring to check your baby’s wellbeing.
Why you might be induced
- if you’re overdue
- if your waters have broken
- if you or your baby have a health problem
If you’re overdue
Induction will be offered if you do not go into labour naturally by 41 weeks, as there will be a higher risk of stillbirth or problems for the baby.
If your waters break early
If your waters break more than 24 hours before labour starts, there’s an increased risk of infection to you and your baby.
If your waters break after 34 weeks, you’ll have the choice of induction or expectant management.
Expectant management is when your healthcare professionals monitor your condition and your baby’s wellbeing, and your pregnancy can progress naturally as long as it’s safe for both of you.
Your midwife or doctor should discuss your options with you before you make a decision.
They should also let you know about the newborn (neonatal) special care hospital facilities in your area.
If your baby is born earlier than 37 weeks, they may be vulnerable to problems related to being premature.
If your waters break before 34 weeks, you’ll only be offered induction if there are other factors that suggest it’s the best thing for you and your baby.
If you have a health condition or your baby is not thriving
You may be offered an induction if you have a condition that means it’ll be safer to have your baby sooner, such as diabetes, high blood pressure or intrahepatic cholestasis of pregnancy.
If this is the case, your doctor and midwife will explain your options to you so you can decide whether or not to have your labour induced.
Membrane sweep
Before inducing labour, you’ll be offered a membrane sweep, also known as a cervical sweep, to bring on labour.
A membrane sweep would usually be offered to you after 39 weeks.
To carry out a membrane sweep, your midwife or doctor sweeps their finger around your cervix during an internal examination.
This action should separate the membranes of the amniotic sac surrounding your baby from your cervix. This separation releases hormones (prostaglandins), which may start your labour.
Some women find the procedure uncomfortable or painful. You may get some cramping and vaginal bleeding afterwards.
If labour does not start after a membrane sweep you may be offered an additional sweep or induction of labour.
Induction is always carried out in a hospital maternity unit. You’ll be looked after by midwives and doctors will be available if you need their help.
How labour is induced
If you’re being induced, you’ll go into the hospital maternity unit.
There are 2 main ways labour can be induced:
- Hormones can be put inside your vagina using a vaginal tablet (pessary) or a gel, or given as tablets that you swallow.
- Devices such as balloon catheter (a small balloon, full of water) or an osmotic dilator (a type of sponge) can be used to widen your cervix.
You’ll usually be offered hormones first to see if they work, unless there’s a medical reason you cannot take hormones.
It usually takes many hours for these treatments to start working. You will usually stay in the hospital maternity unit, though you may be able to go home in some cases.
Sometimes a hormone drip is needed to speed up the labour. You may also need to have your waters broken artificially.
What induced labour feels like
If you need to be induced it may affect where you can give birth. You may need to stay in hospital for longer and have more examinations.
Induced labour is usually more painful than labour that starts on its own.
Your pain relief options during labour are not restricted by being induced.
You should have access to all the pain relief options usually available, such as an epidural or water birth.
If you are induced you’ll be more likely to have an assisted delivery, where forceps or ventouse suction are used to help the baby out.
If induction of labour does not work
Induction is not always successful, and labour may not start.
Your obstetrician and midwife will assess your condition and your baby’s wellbeing. You may be offered another method of induction or a caesarean section, or you may be able to wait a few hours and then be assessed again.
Your midwife and doctor will discuss all your options with you.
Natural ways to start labour
There are no proven ways of starting your labour yourself at home.
You may have heard that certain things can trigger labour, such hot baths, certain food or drinks, having sex or herbal supplements. But there’s no evidence that these work. Also there’s no information about the safety of herbal supplements and they could be harmful to you or your baby.
Having sex will not cause harm, but you should avoid having sex if your waters have broken as there’s an increased risk of infection.
For more information on induction, you can read the NICE information for the public on induction of labour.
Video: When would I be induced and what’s involved?
In this video, a midwife describes what an induction of labour is and what is involved.
