From the Bishop score to cervical ripening doses, from oxytocin regimens to the ARRIVE discussion and the week 41 induction decision; Guideline-based management of induction.
⚕️ Target audience: This clinical review is intended for physicians and healthcare professionals; It is a summary of current literature and guidelines for educational purposes. Clinical decisions should be made based on patient-specific evaluation and applicable institutional protocols.
Induction of labor is performed when the risk of continuing the pregnancy is considered to be equal to or greater than the risk of birth. The frequency of application is rapidly increasing: in the USA, the induction rate increased from 9.5% in 1990 to 34.5% in 2024 (CDC 2024; UpToDate 2026). This increase is due to both the expansion of the indication list and the establishment of the concept of "risk-reducing" induction at the 39th week. This review covers cervical ripening techniques, oxytocin protocols, definition of failed induction, and management of postterm pregnancy; Induction after previous cesarean section is a separate topic.
Induction is indicated when the maternal/fetal risks associated with maintaining the pregnancy are considered to be at least equal to the maternal/perinatal risks associated with delivery. The risk of maintaining the pregnancy depends mainly on the severity of the maternal/fetal condition, and the risk of birth depends mainly on the week of pregnancy (neonatal morbidity). Frequent indications: postterm pregnancy, prelabor membrane rupture, hypertensive diseases of pregnancy (preeclampsia, eclampsia, HELLP, gestational and chronic hypertension), pregestational and gestational diabetes, fetal growth restriction, twin pregnancy, clinical chorioamnionitis, placental abruption, oligohydramnios, intrahepatic cholestasis of pregnancy, alloimmunization with fetal anemia and fetal death. (UpToDate 2026).
The risks of labor and vaginal birth are considered greater than the risks of cesarean section in the following cases; induction is contraindicated: previous classic or other high-risk cesarean section incision, previous uterine rupture, previous large incision involving the entire layer of the myometrium, active genital herpes simplex infection, placenta previa or vasa previa, umbilical cord prolapse or persistent funic presentation, transverse fetal posture, invasive cervical cancer, and category III fetal heart rate (FHR) monitoring (UpToDate 2026).
Pre-induction evaluation includes: review of data on which gestational age and estimated delivery date are based, determination of fetal presentation, fetal weight estimation, cervical examination (is maturation agent required), evaluation of FHR monitoring, and review of risk factors that may cause problems during labor (history of shoulder dystocia, history of postpartum bleeding) (UpToDate 2026).
The likelihood that induction will result in vaginal delivery depends on both cervical and non-cervical factors. The Bishop score is the most widely used cervical assessment system in the United States and is based on five elements: cervical dilation, effacement, consistency, position, and station of the presenting part. Dilation is the most important of the five elements. The scoring system was originally developed in multiparous patients at ≥36 weeks of gestation with an uncomplicated obstetric history, and today it is used in all patients undergoing induction (UpToDate 2026).
| Component | Score range | Note |
|---|---|---|
| Cervical dilation | 0–3 | The most decisive of the five elements |
| Cervical effacement | 0–3 | — |
| Level of the presenting part (station) | 0–3 | — |
| Cervical consistency | 0–2 | — |
| Cervical position | 0–2 | — |
| Total | 0–13 | Common interpretation: ≥6 favorable, ≤3 unfavorable, 4–5 gray area. There is no universally accepted threshold |
Noncervical factors also increase the likelihood of success: multiparity, rupture of membranes, low body mass index, taller height, lower estimated fetal weight, and absence of comorbidities associated with placental insufficiency (e.g., preeclampsia). Despite its limitations, the Bishop score performs as well as — or even better than — ultrasonographic cervical length measurement or fetal fibronectin level in predicting induction success (UpToDate 2026).
An important misunderstanding: an unfavorable cervix does not mean "the chances of a vaginal birth are higher if I avoid induction and watch by waiting." Patients with an unfavorable cervix are also at high risk for cesarean section in expectant management, and in the ARRIVE study the cesarean rate was found to be lower with induction regardless of cervical status (ARRIVE, NEJM 2018).
If the cervix is unfavorable, cervical ripening is generally performed before induction; this shortens the duration of oxytocin administration and increases the likelihood of vaginal delivery. Compared with oxytocin alone, cervical ripening likely increases the chance of vaginal delivery within 24 hours and does not increase—and may reduce—the risk of cesarean delivery. Many clinicians consider a Bishop score <6 an indication for ripening, while some use a lower threshold (≤3 or 4); UpToDate recommends a ripening agent for a Bishop score ≤3 [Grade 1B], for scores of 4–6 the decision is guided jointly by cervical and noncervical factors (including patient preference), and at >6 ripening is considered unnecessary (UpToDate 2026).
There are two main methods: mechanical (balloon catheter, hygroscopic dilator) and pharmacological (prostaglandins). A single method may be used, or mechanical and pharmacological methods may be used simultaneously or sequentially. Once ripening is initiated, it is continued until the cervix becomes favorable; there is no evidence-based time limit prohibiting continued ripening with the same or a different method when the cervix remains unfavorable after 12, 24, or more hours (UpToDate 2026).
| Method | Application | Contraindications and caution |
|---|---|---|
| Single balloon catheter (e.g. Foley) | The balloon is inserted into the extraamniotic space through the endocervical canal and inflated with 30–80 mL of physiological saline; It is gently pulled back to fit into the internal os. Traction can be applied (shortens the time for spontaneous expulsion, but does not shorten the time until birth). It is usually left in place until it is expelled; if it is not expelled, remove it at the planned time (6 or 12 hours). | A lower-positioned placenta is a relative contraindication (the edge of the placenta may be damaged during insertion). Most clinicians do not insert a balloon in cases of membrane rupture; If membranes rupture after insertion, common practice is to remove the device. There are no systemic side effects; The rate of tachysystole is lower than prostaglandins. GBS colonization is not a contraindication |
| Double balloon catheter | The distal (intrauterine) balloon is inflated with 40 mL, the proximal (vaginal) balloon with 20 mL physiological saline; If in the correct position, each can be inflated to 80 mL. No traction required | No clinically important outcome differences compared with single-balloon catheter in meta-analysis; single balloon catheter is cheaper and easier to find |
| Hygroscopic dilators (laminaria, Dilapan-S) | As many dilators as possible are placed in the endocervical canal without using excessive force. Laminaria is removed after 12–24 hours, synthetic dilators after 6–8 hours | It does not protrude from the introitus and does not require traction; it may be more expensive than a balloon catheter. In a 2025 individual participant data meta-analysis (4 randomized trials), Dilapan-S was as effective as other methods (uncomplicated vaginal birth 65% vs. 63%) and had a lower composite rate of complications/adverse effects during cervical ripening (19% vs. 47%). |
| Misoprostol (PGE 1 ) | 25 mcg vaginally every 3–6 hours; or 25 mcg orally every 2 hours (WHO recommendation). If necessary, oxytocin is started 4 hours after the last misoprostol dose. In cases of insufficient uterine activity, 50 mcg vaginally every 6 hours may be appropriate, but the risk of tachysystole is higher. | 🔴 Previous cesarean section or other major uterine surgery with significant damage to the myometrium is a contraindication to misoprostol (risk of uterine rupture). Existing regular painful uterine activity is a relative contraindication. It is off-label use in the USA. |
| Dinoprostone (PGE 2 ) — endocervical gel (Prepidil) | 0.5 mg dinoprostone in 2.5 mL gel, endocervical. If cervical change is insufficient and uterine activity is minimal, it can be repeated in 6–12 hours; The manufacturer recommends not to exceed a cumulative dose of 1.5 mg (three doses) in 24 hours. Oxytocin is initiated 6–12 hours after the last dose | Allergy to prostaglandins and contraindications to labor/vaginal delivery are absolute contraindications. Once the gel is applied it cannot be undone; Tocolytic (e.g. terbutaline 250 mcg subcutaneous) can be given in tachysystole |
| Dinoprostone — vaginal insert (Cervidil) | Timed-release insert containing 10 mg dinoprostone, releasing 0.3 mg per hour. Leave in place until active action begins or for 12 hours. Oxytocin can be started 30 minutes after removal | Its theoretical advantage is that it can be removed in cases of tachysystole or FHR abnormality; Removing the insert usually reduces uterine contractility and does not prolong the time until birth |
There is no single "best practice" for method selection. A 2016 network meta-analysis comparing misoprostol (oral, vaginal), dinoprostone, and balloon catheter concluded that neither method was clearly superior in terms of failure to achieve vaginal delivery within 24 hours, tachysystole with adverse FHR changes, and cesarean section rates (Chen 2016, BJOG network meta-analysis). In detail: vaginal misoprostol or vaginal dinoprostone reduces the risk of not achieving vaginal delivery within 24 hours but increases the risk of hyperstimulation with adverse FHR changes; Balloon catheter has the lowest risk of hyperstimulation, and oral misoprostol has the lowest risk of cesarean section (Chen 2016).
Concurrent use of mechanical and pharmacological methods is becoming increasingly common. In a network meta-analysis of 30 randomized trials involving 6465 pregnancies, balloon catheter plus prostaglandin or balloon catheter plus oxytocin shortened the time to vaginal birth compared with balloon catheter alone (by −2.9 hours, 95% CI −5.7 to 0; and −4.2 hours, −6.5 to −1.9, respectively) and increased the likelihood of birth within 24 hours (OR 1.80, 1.02–3.20, and OR 2.04, 1.29–3.24). No significant difference was found in cesarean risk or adverse events (chorioamnionitis, endometritis, tachysystole, meconium, neonatal intensive care admission, postpartum hemorrhage) (30 randomized trials, 6465 pregnancies—UpToDate 2026). Evidence is insufficient to determine the preferred combination or optimal protocol.
Outpatient maturation can be performed in selected patients; In the USA, the preference is for mechanical methods because prostaglandins carry a higher probability of tachysystole. Because large studies have not yet been conducted large enough to show meaningful results, there is no evidence to recommend any particular approach, and institutional practices vary widely. There are contraindications to outpatient maturation — since continuous monitoring and rapid intervention are not possible: fetal growth restriction, oligo/polyhydramnios, multiple pregnancy, major anomaly, unreliable fetal tests; previous cesarean section or uterine surgery involving the entire layer of the myometrium, clinically significant vaginal bleeding, hypertensive disease of pregnancy, and inability to return to hospital quickly when necessary (UpToDate 2026).
Synthetic oxytocin is the most common and proven method of induction; In a network meta-analysis, IV oxytocin + amniotomy and ≥50 mcg vaginal misoprostol were the two approaches most likely to result in vaginal birth within 24 hours. Oxytocin cannot be given orally (it is broken down by gastrointestinal enzymes); When given IV, the plasma half-life is three–six minutes, and it takes approximately 40 minutes for any dose to reach steady state and maximum contractile response—the basis for low-dose protocols (UpToDate 2026).
Oxytocin is given by infusion pump. A common regimen is to prepare 60 units of oxytocin in 1000 mL of crystalloid (60 milliunits per mL); Thus, the pump speed (mL/hour) exactly matches the applied dose (milliunits/minute) and application error is reduced. The dose is increased until labor progression normalizes or contractions occur on palpation of at least moderate intensity, every two to three minutes (three to four contractions in 10 minutes), and last for at least 60 seconds—corresponding to approximately 200–250 Montevideo units (UpToDate 2026).
If cervical ripening has been performed, it is important when to start oxytocin, because prostaglandin increases the sensitivity of the uterus to oxytocin and simultaneous administration increases the frequency of tachysystole: 6–12 hours after the last dose of dinoprostone gel, 30 minutes after removal of the dinoprostone insert, 4 hours after the last dose of misoprostol. If maturation is performed with a balloon catheter, oxytocin can be initiated while the catheter is in place or after it is removed (UpToDate 2026).
| Outcome | High dose regimen | Source / comment |
|---|---|---|
| Time until birth | 0.63 hours shorter on average (95% CI −0.85 to −0.41) | 2025 meta-analysis; 10 randomized studies, 5508 pregnancies |
| Spontaneous vaginal birth | 74.4% vs 69% (RR 1.10; 1.03–1.18) | Modest increase |
| Caesarean section | 12.4% vs 14.5% (RR 0.83; 0.67–1.02) | Statistically similar |
| Chorioamnionitis | 8.9% vs 12.9% (RR 0.70; 0.57–0.84) | Decreases with high dose |
| Tachysystole | 39.6% vs 28.8% (RR 1.32; 1.21–1.43) | 🔴 The main cost of high dose |
| Postpartum hemorrhage, endometritis, uterine rupture, shoulder dystocia, pH <7.10, 5th minute Apgar <3, neonatal intensive care unit admission, neonatal death | Similar | No difference detected between the two regimes |
As a result, either a low or high dose regimen is acceptable for most patients; The decision depends on local factors (clinician/institution preference, monitoring resources). In patients with previous cesarean section or extensive transmyometrial surgery, some authors recommend a low-dose regimen; The maximum safe dose in this group is unclear, and the commonly used limit of 20 milliunits/minute is somewhat arbitrary. While many institutions limit infusion to a live fetus in the third trimester to 40 milliunits/minute, doses up to 90 milliunits/minute have been used in randomized studies without adverse maternal or fetal effects; Therefore, it is advocated to titrate the dose according to the patient's contraction and FHR pattern rather than an arbitrary maximum (UpToDate 2026).
The risk of uterine rupture is very low in a scarless uterus: in a series of more than 226,000 births, 14 ruptures occurred in patients with a scarless uterus, 12 of which occurred in patients exposed to oxytocin for induction or augmentation. The attribution of postpartum bleeding to oxytocin is most likely confounding by indication; In studies comparing induction with expectant management, induction did not increase the risk of postpartum bleeding (UpToDate 2026).
There is no consensus on whether oxytocin should be discontinued when labor enters the active phase (cervical dilatation ≥6 cm); Randomized data did not clearly show that one strategy worked better. Both approaches are reasonable if labor is progressing and the FHR pattern is reassuring. Routine “oxytocin timeout” (stopping medication when no progress is made and restarting hours later) is not recommended — although oxytocin receptor desensitization has been demonstrated in vitro, the benefit of this approach has not been proven in randomized trials (UpToDate 2026).
The combined use of oxytocin and amniotomy shortens the time to vaginal birth compared to oxytocin alone. Early amniotomy is safe and effective: in a 2020 meta-analysis combining four randomized trials (1273 patients), early amniotomy after cervical ripening shortened the time from induction to birth by approximately five hours (95% CI −8.12 to −1.78), without affecting the caesarean section rate (31.1% versus 30.9%; RR 1.05, 0.71–1.56; UpToDate 2026). In a 2024 meta-analysis (5 studies, 849 participants) comparing early and late amniotomy in patients undergoing balloon catheter maturation, early amniotomy increased the rate of birth within 24 hours (79.9% vs 67.1%; RR 1.19, 1.04–1.36); No significant difference was detected in cesarean section, chorioamnionitis, intrapartum fever, endometritis, cord prolapse and neonatal sepsis (2024 meta-analysis; UpToDate 2026).
Amniotomy is performed as soon as possible if the fetal head is well applied to the cervix; if it is not well applied, amniotomy is deferred to reduce the risk of cord prolapse. Its complications—rupture of vasa previa, if present, and umbilical cord prolapse—can also occur with spontaneous membrane rupture. With a favorable cervix, amniotomy alone is an option, but amniotomy plus IV oxytocin is significantly more effective: in a meta-analysis, the proportion of pregnancies undelivered at 24 hours was 2.1% versus 16.3% (RR 0.13; 0.04–0.41; UpToDate 2026).
Membrane sweeping is the separation of membranes from the decidua by inserting the examining finger beyond the internal cervical os and rotating it circumferentially along the lower uterine segment. It should only be performed in patients for whom a trial of labor is planned and who are at least 39 weeks gestation. In a 2020 meta-analysis involving forty randomized trials and more than 6,500 participants, stripping modestly reduced the rate of formal induction (23% vs. 31%; RR 0.73, 0.56–0.94) and increased the rate of spontaneous onset of labor (72% vs. 60%; RR 1.21, 1.08–1.34); did not affect other maternal and neonatal outcomes (2020 meta-analysis; 40 randomized trials). Since it may cause significant discomfort, the patient should be informed and verbal consent should be obtained before the procedure. GBS colonization is not a contraindication.
There are insufficient safety and/or efficacy data for corticosteroids, castor oil, hyaluronidase, isosorbide mononitrate, acupuncture, evening primrose oil, herbal preparations, breast stimulation, and sexual intercourse; None of these can be recommended as an evidence-based induction method (UpToDate 2026).
Historically, birth at 41 or 42 weeks was considered an indication, with birth at earlier (but term) weeks being described as "elective". Today, “risk-reducing induction” is considered a more accurate term due to consistent evidence showing that once full term is reached, outcomes are equivalent to—in some cases, better—than expectant management (UpToDate 2026).
The evidence base is the ARRIVE trial: a multicenter randomized trial comparing planned induction versus expectant management at 39 0/7 – 39 4/7 weeks in more than 6100 low-risk nulliparous patients across the United States. Induction yielded the following results (ARRIVE, NEJM 2018):
The discussion after ARRIVE continued on two axes. First, real-world generalizability: meta-analyses, mostly from observational studies, support that risk-reducing induction at week 39 shows efficacy similar to the efficacy demonstrated in ARRIVE in typical clinical settings. No large-scale randomized trials have been conducted in low-risk multiparous patients; Observational studies in this population have reported results similar to ARRIVE (UpToDate 2026). Second, long-term: data on children's neurodevelopmental outcomes are limited but appear similar for the two groups (UpToDate 2026).
Agency positions: ACOG concluded that offering induction at ≥39 0/7 weeks to nulliparous patients without medical indication is a reasonable option that the patient and physician should discuss; This recommendation is for well-dated pregnancies, and ACOG advises against risk-reducing induction in poorly dated pregnancies (ACOG). ACOG also states that maternal anxiety or discomfort associated with a normal pregnancy, the patient's distance from home, or a history of shoulder dystocia in a previous pregnancy are not appropriate indications for early-term (37 0/7 – 38 6/7 weeks) induction. SMFM also concluded that it is reasonable to offer risk-reducing induction at ≥39 0/7 weeks to low-risk nulliparous patients and recommended that physicians choosing this approach ensure that their patients meet the eligibility criteria of the ARRIVE study (SMFM 2019).
Risk-reducing induction should be avoided before 39 0/7 weeks. The morbidity of birth before 37 0/7 weeks (preterm birth) is well-established; Early term birth (37 0/7 – 38 6/7 weeks) is also associated with higher neonatal morbidity and healthcare utilization throughout the first year compared to birth at 39 0/7 – 40 6/7 weeks. In the USA, the National Quality Forum, The Joint Commission and the Leapfrog Group have made it a maternal performance measure ("39-week rule"; UpToDate 2026).
The average duration of the latent phase in induction is longer than in spontaneous labor. However, once the patient enters the active phase (cervical dilatation ≥6 cm), the progression becomes comparable to that in spontaneous labor, and the duration of the second phase is similar; therefore, active phase and second phase prolongation/arrest disorders are recognized and managed as in spontaneous labor (UpToDate 2026).
There is no strong consensus on the definition of failed induction. A reasonable approach is to reserve the term only for cesareans performed in the latent phase—as this phase has been going on for a long time and is unlikely to enter the active phase with maintenance of oxytocin, based on the clinician's assessment. This term is not used for caesarean sections performed due to active phase prolongation/arrest, prolonged second stage, unreliable fetal status, or maternal indication requiring urgent delivery; Induction that is stopped and sent home before giving birth to the patient is interrupted induction (UpToDate 2026).
Patience criterion: In 2024, ACOG and SMFM recommended that oxytocin be administered for at least 12–18 hours after membrane rupture before considering induction failure if the maternal and fetal status remains reassuring, and that the decision to exceed 18 hours should be individualized. This threshold is based on latent phase data: in a large multicenter study, approximately 70% of nulliparous patients emerged from the latent phase with oxytocin and within 6 hours of membrane rupture, with 20% emerging from the latent phase between 6–12 hours. Of the 5% group that remained in the latent phase for more than 12 hours, 40% had a vaginal birth. In another multicenter study, 96% of nulliparous patients reached the active phase within 15 hours. These criteria virtually eliminate unsuccessful induction in multiparous patients (ACOG/SMFM 2024).
Term pregnancy is subdivided into: early term 37 0/7 – 38 6/7 weeks, full term 39 0/7 – 40 6/7 weeks, late term 41 0/7 – 41 6/7 weeks, and postterm ≥42 0/7 weeks (≥294 days from the first day of the last menstrual period and/or ≥14 days after the estimated due date). In US birth certificate data, 0.27% of pregnancies are born at ≥42 weeks and 5.2% are born at ≥41 weeks; In Europe, the rate varies widely between countries (0.4–0.6% in Austria and Belgium; 7.5–8.1% in Sweden and Denmark; ACOG Committee Opinion 579, 2013; UpToDate 2026).
One of the most important factors determining prevalence is early ultrasonographic dating: Routine (rather than selective) ultrasound before 24 weeks reduced the likelihood of induction due to postterm pregnancy by approximately 50% (1.4% vs 2.8%; RR 0.48, 0.31–0.73 — UpToDate 2026). Most postterm pregnancies have no known etiology; Between one-third and one-half of the variability in the population can be attributed to maternal or fetal genetic effects. The strongest risk factor is previous postterm pregnancy (relative risk ≥2); More modest risk factors are nulliparity, male fetus, obesity, advanced maternal age, and the mother's own postterm birth history (UpToDate 2026).
Most complications are the result of either excessive fetal growth or uteroplacental insufficiency. Macrosomia is more common in postterm neonates (birth weight ≥4500 g: 2.5–10% postterm versus 0.8–1% term) and increases the risks of abnormal labor progression, cesarean section, assisted vaginal delivery, shoulder dystocia, birth trauma, postpartum hemorrhage, and neonatal metabolic problems. However, not all postterm fetuses continue to grow: up to 20% develop fetal dysmaturity (postmaturity) syndrome with features of chronic malnutrition. These fetuses are at risk for cord compression due to oligohydramnios and abnormal FHR patterns due to uteroplacental insufficiency; Passage of meconium is common. Dysmature newborns have long thin bodies, long nails and are small for their gestational age; their skin is dry (vernix caseosa reduced or absent), meconium-stained, parchment-like, and peeling (UpToDate 2026).
| Week of pregnancy | Antepartum fetal death per 1000 ongoing pregnancies |
|---|---|
| 40–41 weeks | 0.86 – 1.08 |
| 41–42 weeks | 1.2 – 1.27 |
| 42–43 weeks | 1.3 – 1.9 |
| >43 weeks | 1.58 – 6.3 |
In relative terms, the perinatal mortality rate at ≥42 weeks is twice that at term, four times at 43 weeks, and five to seven times at 44 weeks; Neonates born at ≥41 weeks have a one-third higher risk of neonatal mortality than those born at 38–40 weeks. However, the absolute risk is low (table). It is unclear whether and to what extent perinatal mortality is increased in postterm pregnancies without fetal anomaly, evidence of placental insufficiency (growth restriction, oligohydramnios), or maternal impairment associated with adverse pregnancy outcome (diabetes, hypertension): in a pooled analysis, 3914 such pregnancies after 42 weeks had two perinatal deaths (0.05%; UpToDate 2026).
In singleton, cephalic, and otherwise uncomplicated pregnancies, once 41 0/7 weeks is reached, there are two options: induction or expectant management with fetal assessment. UpToDate favors induction at or shortly after 41 0/7 weeks regardless of cervical status [Grade 2B]; A ripening agent (balloon catheter and/or prostaglandin) is applied to the unfavorable cervix (UpToDate 2026).
Expectant management is also a defensible option: the absolute rate of perinatal death at ≥41 weeks is relatively low (approximately 3.0 per 1000 pregnancies with expectant management, 0.4 with induction), more than 400 inductions are required to prevent one perinatal death, and some pregnant women place high value on spontaneous onset of labor. In expectant management, fetal monitoring is performed twice a week from 41 0/7 weeks (or shortly thereafter): nonstress test + amniotic fluid assessment or biophysical profile; There is no convincing evidence that one is superior to the other. It is important to evaluate amniotic fluid twice a week because amniotic fluid can decrease rapidly within 24–48 hours. There is no proven benefit in monitoring the postterm fetus with umbilical artery Doppler alone; Evaluation of uterine artery, middle cerebral artery, descending aorta, ductus venosus, or vena cava inferior pulsatility indices is also not useful (UpToDate 2026).
Institutional positions: ACOG recommends discussing the potential benefits and risks of induction at ≥39 weeks with the patient compared with pending management; It recommends induction after 42 0/7 weeks and up to 42 6/7 weeks in patients who refuse induction and exceed the estimated delivery date, and considers induction between 41 0/7 and 42 0/7 as reasonable. UpToDate and professional guides generally converge on routine induction between 41 0/7 – 42 0/7; The exact timing within this week is left to local conditions and physician and patient preference. In patients who wish to avoid standard maturation agents and/or induction, membrane stripping may reduce the rate of pregnancies remaining unborn at 42 weeks (ACOG; UpToDate 2026).
The risk of a second postterm birth increases two to fourfold after one postterm pregnancy and becomes even higher after two postterm pregnancies. In the Dutch Perinatal Registry database (more than 230,000 patients), while the postterm birth rate in the first pregnancy was 7.7%, in the second pregnancy this rate was found to be 15% in those whose previous birth was postterm and 4% in those who had a term (Dutch Perinatal Register; UpToDate 2026).
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