Delivery outcomes in women with morbid obesity, where induction of labour was planned to prevent post-term complications.

Morbid obesity and prolonged pregnancy are independently associated with adverse delivery and perinatal outcomes. We conducted a retrospective observational study on otherwise uncomplicated women with a body mass index (BMI) ≥ 40 kg/m2 where, having reached term, induction of labour (IOL) was planned, to prevent prolonged pregnancy. The primary aim was to describe delivery outcomes and short-term maternal and perinatal adverse events. Of 117 cases included, 69 (59%) laboured spontaneously before the induction date, while 48 (41%) required an IOL. Of 48 patients that underwent an IOL, 22 (45.8%) achieved vaginal delivery, compared to 55 (79.7%) who laboured spontaneously (p = <.001). Twenty-two (18.8%) of the 117 babies weighed more than 4000 g, with 13 of these delivered vaginally. Overall, term patients with morbid obesity who laboured spontaneously before requiring induction, had a high rate of vaginal delivery. However, when IOL was required, the rate of caesarean delivery rose dramatically.Impact statementWhat is already known on this subject? Morbid obesity and prolonged pregnancy are independently associated with adverse delivery and perinatal outcomes. Induction of labour (IOL) increases the workload in busy units.What do the results of this study add? These results help inform accurate counselling on delivery outcomes, which is integral to respectful care, for the continuously increasing numbers of morbidly obese pregnant women.What the implications are of these findings for clinical practice and/or further research? It is preferable to avoid semi- or urgent caesarean deliveries in morbidly obese women after IOL. The outcomes of earlier induction of labour from 39- or 40-weeks' gestation requires investigation. Earlier induction may reduce the numbers of caesarean deliveries for abnormal cardiotocograph during the process.

Prostaglandin-Endoperoxide Synthase 1 Mediates the Timing of Parturition in Mice Despite Unhindered Uterine Contractility.

Cyclooxygenase (COX)-derived prostaglandins stimulate uterine contractions and prepare the cervix for parturition. Prior reports suggest Cox-1 knockout (KO) mice exhibit delayed parturition due to impaired luteolysis, yet the mechanism for late-onset delivery remains unclear. Here, we examined key factors for normal onset of parturition to determine whether any could account for the delayed parturition phenotype. Pregnant Cox-1KO mice did not display altered timing of embryo implantation or postimplantation growth. Although messenger RNAs of contraction-associated proteins (CAPs) were differentially expressed between Cox-1KO and wild-type (WT) myometrium, there were no differences in CAP agonist-induced intracellular calcium release, spontaneous or oxytocin (OT)-induced ex vivo uterine contractility, or in vivo uterine contractile pressure. Delayed parturition in Cox-1KO mice persisted despite exogenous OT treatment. Progesterone (P4) withdrawal, by ovariectomy or administration of the P4-antagonist RU486, diminished the delayed parturition phenotype of Cox-1KO mice. Because antepartum P4 levels do not decline in Cox-1KO females, P4-treated WT mice were examined for the effect of this hormone on in vivo uterine contractility and ex vivo cervical dilation. P4-treated WT mice had delayed parturition but normal uterine contractility. Cervical distensibility was decreased in Cox-1KO mice on the day of expected delivery and reduced in WT mice with long-term P4 treatment. Collectively, these findings show that delayed parturition in Cox-1KO mice is the result of impaired luteolysis and cervical dilation, despite the presence of strong uterine contractions.

Inducción del parto (actualizado julio del 2013) / Induction of labour (updated July 2013)

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Reduction in stillbirths at term after new birth induction paradigm: results of a national intervention.

OBJECTIVE: The risk of fetal death increases steeply after 42 gestational weeks. Since 2009, Denmark has had a more proactive policy including prevention of prolonged pregnancy, and early intervention in women with diabetes, preeclampsia, high body mass index and of a higher age group. The aim of this study was to describe the development in fetal deaths with this more proactive birth induction practice, and to identify and quantify contributing factors for this development. DESIGN: National cohort study. SETTING: Denmark. PARTICIPANTS: Delivering women in Denmark, 1 January 2000 to 31 December 2012. OUTCOME MEASURES: Stillbirths per 1000 women at risk (prospective risk of stillbirth) and per 1000 newborn from 37 and 40 gestational weeks, respectively, through the study period. RESULTS: During the study period, 829,165 children were live born and 3770 (0.45%) stillborn. Induction of labour increased from 12.4% in year 2000 to 25.1% in 2012 (p<0.001), and the percentage of children born at or after 42 weeks decreased from 8.0% to 1.5% (p<0.001). Through the same period, the prospective risk of stillbirth after 37 weeks fell from 0.70 to 0.41/1000 ongoing pregnancies (p<0.001), and from 2.4 to 1.4/1000 newborn (p<0.001). The regression analysis confirmed the inverse association between year of birth and risk of stillbirth. The lowest risk was observed in the years 2011-2012 as compared with years 2000-2002 with a fully adjusted HR of 0.69 (95% CI 0.57 to 0.83). The general earlier induction, the focused earlier induction of women with body mass index >30, twins, and of women above 40 years and a halving of smoking pregnant women were all independent contributing factors for the decrease. CONCLUSIONS: A gradually more proactive and differential earlier labour induction practice is likely to have mainly been responsible for the substantial reduction in stillbirths in Denmark.

Membrane stripping to prevent post-term pregnancy in Enugu, Nigeria: a randomized controlled trial.

OBJECTIVES: This study aimed at evaluating the effectiveness and safety of membrane stripping at 40-41 weeks of gestation as a means of preventing post-term pregnancy and the need for formal induction of labor in Enugu, Nigeria. METHODOLOGY: A randomized controlled trial of 134 post-date pregnant women at the University of Nigeria Teaching Hospital, Enugu, Nigeria, from February to November 2012. The intervention group received membrane stripping while the control group did not receive membrane stripping. RESULTS: The incidence of post-term pregnancy in the membrane stripping group was 16.1% (10/62) versus 39.3% (24/61) in the control group (RR 0.41; 95% CI 0.22-0.78; P = 0.004; NNT = 4). Membrane stripping reduced the duration of pregnancy by 3 days (P < 0.001). The procedure also significantly reduced the need for 'formal' labor induction [7/62 (11.3%) vs. 23/61 (37.7%); RR 0.30; 95 CI 0.14-0.65; P = 0.002]. However, maternal and neonatal complications were similar between the two groups. CONCLUSION: Membrane stripping reduces the incidence of post-term pregnancy and need for formal induction of labor in post-date pregnant women, without increased maternal or neonatal complications.

Risk factors for cesarean delivery after induction of labor in nulliparous women with an unfavorable cervix at or beyond 41 weeks of gestation.

AIMS: To investigate risk factors for cesarean section (CS) following labor induction in nulliparas with an unfavorable cervix at or beyond 41 weeks of gestation. METHODS: In this retrospective cohort study, a total of 276 nulliparas with an unfavorable cervix (Bishop score ≤6) who underwent labor induction for prolonged pregnancies were included out of a total of 646 patients who delivered ≥41 weeks (2002-2011). RESULTS: 82 (29.7%) patients of the 276 delivered by CS. The patients who underwent CS had less cervical dilatation and a lower Bishop score on admission than those patients who delivered vaginally (0.76 ± 0.47 vs. 0.92 ± 0.58 cm, p = 0.03 and 1.16 ± 1.25 vs. 1.51 ± 1.34, p = 0.04, respectively). Neonatal birth weight and biparietal diameter (BPD) were significantly smaller in the vaginal delivery group (3,414.93 ± 361.37 vs. 3,534.81 ± 383.05 g, p = 0.01 and 9.43 ± 0.35 vs. 9.65 ± 0.42 cm, p < 0.01). After multiple logistic regression analysis, maternal height, BPD, and early rupture of membranes (ROM) were independently related with CS. Early ROM was defined as spontaneous ROM that occurred before the onset of the active phase of labor. CONCLUSION: Maternal height, BPD, and early ROM were risk factors for CS following labor induction in nulliparas at or beyond 41 weeks of gestation.

Induction of labour versus expectant management for nulliparous women over 35 years of age: a multi-centre prospective, randomised controlled trial.

BACKGROUND: British women are increasingly delaying childbirth. The proportion giving birth over the age of 35 rose from 12% in 1996 to 20% in 2006. Women over this age are at a higher risk of perinatal death, and antepartum stillbirth accounts for 61% of all such deaths. Women over 40 years old have a similar stillbirth risk at 39 weeks as women who are between 25 and 29 years old have at 41 weeks.Many obstetricians respond to this by suggesting labour induction at term to forestall some of the risk. In a national survey of obstetricians 37% already induce women aged 40-44 years. A substantial minority of parents support such a policy, but others do not on the grounds that it might increase the risk of Caesarean section. However trials of induction in other high-risk scenarios have not shown any increase in Caesarean sections, rather the reverse. If induction for women over 35 did not increase Caesareans, or even reduced them, it would plausibly improve perinatal outcome and be an acceptable intervention. We therefore plan to perform a trial to test the effect of such an induction policy on Caesarean section rates.This trial is funded by the NHS Research for Patient Benefit (RfPB) Programme. DESIGN: The 35/39 trial is a multi-centre, prospective, randomised controlled trial. It is being run in twenty UK centres and we aim to recruit 630 nulliparous women (315 per group) aged over 35 years of age, over two years. Women will be randomly allocated to one of two groups: Induction of labour between 39°/7 and 396/7 weeks gestation. Expectant management i.e. awaiting spontaneous onset of labour unless a situation develops necessitating either induction of labour or Caesarean Section.The primary purpose of this trial is to establish what effect a policy of induction of labour at 39 weeks for nulliparous women of advanced maternal age has on the rate of Caesarean section deliveries. The secondary aim is to act as a pilot study for a trial to answer the question, does induction of labour in this group of women improve perinatal outcomes? Randomisation will occur at 36°/7-396/7 weeks gestation via a computerised randomisation programme at the Clinical Trials Unit, University of Nottingham. There will be no blinding to treatment allocation. DISCUSSION: The 35/39 trial is powered to detect an effect of induction of labour on the risk of caesarean section, it is underpowered to determine whether it improves perinatal outcome. The current study will also act as a pilot for a larger study to address this question. TRIAL REGISTRATION: ISRCTN11517275.

Is it possible to estimate the minimal clinically important treatment effect needed to change practice in preterm birth prevention? Results of an obstetrician survey used to support the design of a trial.

BACKGROUND: Sample sizes for obstetrical trials are often based on the opinion of investigators about clinically important effect size. We surveyed Canadian obstetricians to investigate clinically important effect sizes required before introducing new treatments into practice to prevent preterm birth. METHODS: Questionnaires were mailed to practicing obstetricians, asking the magnitude of pregnancy prolongation required to introduce treatments into practice. The three prophylactic treatments were of increasing invasiveness: vaginal progesterone, intramuscular progesterone, and cervical cerclage. We also asked about the perceived most relevant outcome measures for obstetrical trials and current obstetrical practice in preterm birth prevention. RESULTS: 544/1293(42.1%) completed questionnaires were received. The majority of respondents required one or two weeks' increase in length of gestation before introducing vaginal (372,77.1%), and intramuscular progesterone(354,67.9%). At least three weeks increase was required before introducing prophylactic cervical cerclage(326,62.8%). Clinicians who already used a treatment required a smaller difference before introducing it into practice. Decreasing neonatal morbidity was cited as the most important outcome for obstetrical trials (349,72.2%). CONCLUSION: Obstetricians would require a larger increase in treatment effect before introducing more invasive treatments into practice. Although infant morbidity was perceived as a more important outcome, clinicians appeared willing to change practice on the basis of prolongation of pregnancy, a surrogate outcome. We found that there is not a single minimum clinically important treatment effect that will influence all practising clinicians: rather the effect size that will influence physicians is affected by the nature of the treatment, the reported outcome measure and the clinician's own current clinical practice.

Finalización electiva versus manejo expectante en el control de la gestación prolongada: estudio prospectivo de 200 gestantes / Elective termination versus expectant management in prolonged pregnancy: a prospective study of 200 pregnant women

Objetivo. Comparar la finalización electiva de la gestación prolongada versus el manejo expectante, en gestaciones de bajo riesgo obstétrico. Material y método. Ensayo clínico controlado y aleatorizado entre actuaciones activas y expectantes, sobre una muestra de 200 mujeres con gestación prolongada de bajo riesgo obstétrico entre febrero de 2003 y junio de 2005 en el Hospital Universitario Materno-Infantil de Canarias. Resultados. El grupo estudio está formado por 200 pacientes - 102 del grupo activa y 98 del grupo expectante -. No se encontraron diferencias epidemiológicas entre ambos grupos. El parto no fue inducido en un porcentaje de gestantes significativamente superior en el grupo activa frente al grupo expectante (51% vs 35,7%, p=0,02; OR 0,53 [CI 95% 0,3-0,94]), es decir, el número de inducciones es significativamente superior en el grupo de manejo expectante. Una tasa significativamente menor de gestantes del grupo activa presentó líquido amniótico meconial durante la dilatación (15,7% vs 28,6% p=0,02; OR 0,47 [IC 95% 0,23-0,93]). No existen diferencias significativas con relación al tipo de parto, no obstante el porcentaje de intervención cesárea fue marcadamente inferior en el grupo activa frente al grupo expectante ([12,7% vs 18,4%, p=0,3; OR 0,65 [IC 95% 0.3-1.41]). Los resultados perinatales no muestran diferencias significativas entre ambos grupos. Conclusiones. La finalización electiva en el semana 42, en gestaciones de bajo riesgo obstétrico con condiciones cervicales desfavorables, parece reducir la tasa de cesáreas sin comprometer los resultados perinatales (AU)

Objective. To compare elective termination versus expectant management in low-risk prolonged pregnancy. Material and method. We performed a controlled randomized clinical trial comparing the results of active and expectant approaches in the management of low-risk prolonged pregnancy in a sample of 200 women between February 2003 and June 2005 at the Maternity Ward of the Canary Islands University Hospital. Results. The study group consisted of 200 patients. There were 102 in the active management group and 98 in the expectant management group. No between-group epidemiologic differences were found. Labor was not induced in a significantly higher proportion of patients in the active than in the expectant group [51% vs 35.7%, p=0.02; OR 0.53 (95% CI 0.3-0.94)] i.e. the induction rate was significantly higher in the expectant group. The proportion of patients with meconium-stained amniotic fluid during labor was significantly lower in the active management group [15.7% vs 28.6% p=0.02; OR 0.47 (95% CI 0.23-0.93)]. No significant differences were found in the type of delivery, although the proportion of cesarean sections was noticeably lower in the active management than in the expectant management group [(12.7% vs 18.4%, p=0.3; OR 0.65 (95% CI 0.3-1.41)]. No significant differences were found in perinatal outcomes between the two groups. Conclusions. Elective termination of low-risk pregnancies with unfavorable cervical findings at week 42 seems to reduce the rate of cesarean section without impairing perinatal outcome (AU)

Postterm pregnancy: how can we improve outcomes?

UNLABELLED: Postterm pregnancy is defined as one which has progressed to 42 0/7 weeks or beyond. The most common reason to be diagnosed with a postterm pregnancy is inaccurate pregnancy dating, but it is also associated with obesity, nulliparity, and a prior history of postterm pregnancy. The rate of postterm pregnancy appears to be decreasing whether due to improved pregnancy dating or an increase in induction of labor. Postterm pregnancy is associated with both maternal and neonatal morbidity and fetal and neonatal mortality; similarly pregnancies beyond 41 weeks' gestation are associated with increases in these perinatal complications. Prevention of postterm pregnancies may include stripping or sweeping the membranes and unprotected coitus. Management of such pregnancies may include induction of labor and fetal antenatal monitoring. Individual patient management should involve careful counseling regarding the risks and benefits of each of the components of care. TARGET AUDIENCE: Obstetricians & Gynecologists, Family Physicians. LEARNING OBJECTIVES: After completion of this article, the reader should be able to recall the increasing risks of poor outcomes associated with prolonged pregnancy, demonstrate knowledge regarding gestational dating and use of cervical ripening agents in their care of pregnant women, and use evidence-based information when counseling their term patients regarding postterm pregnancy management.

Obstetric outcome in post-term pregnancies: time for reappraisal in clinical management.

BACKGROUND: The objective of this study was to determine the outcome of pregnancy in post-term cases compared with term cases in a well defined population receiving modern obstetric care. METHODS: We utilized the population-based birth registry data of the Kuopio University Hospital (1990-2000) to investigate pregnancy outcome in 1,678 post-term singleton pregnancies. The general obstetric population (n=22,712) was used as a reference group in logistic regression analysis. RESULTS: The overall frequency of post-term pregnancies was 6.9% and the incidence of post-term pregnancies was found to be increased in obese, primiparous, and smoking women, whereas in women with chronic diseases and obstetric risks deliveries were induced earlier. The risks of macrosomia, maternal complications, and operative deliveries were increased in post-term pregnancies. Post-term infants experienced meconium passage (21.2% versus 12.8%) (p<0.01) and intrapartum asphyxia (3.4% versus 2.1%) (p<0.01) significantly more often than the controls. However, the stillbirth rate was low, probably due to careful monitoring of these pregnancies. CONCLUSIONS: Although high-risk pregnancies were not allowed to come post-term, postmaturity per se is a moderate risk state compromising fetal well-being with regard to meconium passage and acid-base status at birth. We conclude that simple antenatal monitoring beyond 42 weeks reduces perinatal mortality but is inefficient in reducing meconium-stained liquor seen with increasing gestation.

Membrane sweeping and prevention of post-term pregnancy in low-risk pregnancies: a randomised controlled trial.

OBJECTIVE: To evaluate the effectiveness of membrane sweeping at 41 weeks for the prevention of post-term pregnancy. DESIGN: A multicentre randomised controlled trial. SETTING: Fifty-one primary care midwifery practices in the Netherlands. POPULATION: A total of 742 low-risk pregnant women at 41 weeks of gestation. METHODS: Participants were randomly assigned to serial sweeping of the membranes (every 48 hours until labour commenced up to 42 weeks of gestation) or no intervention. MAIN OUTCOME MEASURES: Post-term pregnancy (>or=42 weeks). Subgroup analyses were performed on nulliparous and parous women. Secondary outcomes included adverse effects. RESULTS: Serial sweeping of the membranes at 41 weeks decreased the risk of post-term pregnancy (87/375 [23%] versus 149/367 [41%]; relative risk [RR] 0.57, 95% CI 0.46-0.71; number needed to treat [NNT] 6 [95% CI 4-9]). Benefits were also seen in both subgroups (nulliparous: 57/198 [29%] versus 89/192 [46%]; RR 0.62 [95% CI 0.48-0.81]; NNT 6 [95% CI 4-12] and parous: 30/177 [17%] versus 60/175 [34%]; RR 0.49 [95% CI 0.34-0.73]; NNT 6 [95% CI 4-6]). Adverse effects were similar in both the groups except for uncomplicated bleeding, which was reported more frequently in the sweeping group. Other obstetric outcomes and indicators of neonatal morbidity were similar in both groups. There were two perinatal deaths in each group. CONCLUSIONS: Membrane sweeping at 41 weeks can substantially reduce the proportion of women with post-term pregnancy.

Does a first trimester dating scan using crown rump length measurement reduce the rate of induction of labour for prolonged pregnancy? An uncompleted randomised controlled trial of 463 women.

OBJECTIVE: To evaluate the effect of a first trimester ultrasound dating scan on the rate of induction of labour for prolonged pregnancy. DESIGN: Randomised controlled trial to include 400 women in each arm of the trial. SETTING: Participating general practices and a district general teaching hospital. POPULATION: Women attending their general practitioner in the first trimester to confirm pregnancy, in whom a first trimester ultrasound scan was not indicated. METHODS: Women randomised to the study group (scan group) underwent an ultrasound dating scan between 8 and 12 weeks, measuring crown-rump length. The estimated date of delivery (EDD) was changed if there was a discrepancy of more than 5 days from the gestation, calculated from the last menstrual period (LMP). For the remaining women (no-scan group), gestation was determined using the LMP. MAIN OUTCOME MEASURES: The rate of induction of labour for prolonged pregnancy. RESULTS: Due to circumstances beyond the researchers' control, recruitment was abandoned when 463 women had been enrolled. The EDD was adjusted in 13 (5.7%) women in the scan group and in 2 (0.9%) in the no-scan group. There was no difference in the rate of induction for prolonged pregnancy between the scan (19 [8.2%]) and the no-scan (17 [7.4%]) groups (relative risk 1.10; 95% CI 0.59-2.07). CONCLUSIONS: Acknowledging the reduced numbers recruited for study, it is concluded that there is no evidence that a first trimester ultrasound dating scan reduces the rate of induction of labour for prolonged pregnancy and may result in a more expensive healthcare strategy.