Cervical ripening and labor induction: clinical guidelines

A myofibre model for the study of uterine excitation-contraction dynamics

As the uterus remodels in preparation for delivery, the excitability and contractility of the uterine smooth muscle layer, the myometrium, increase drastically. But when remodelling proceeds abnormally it can contribute to preterm birth, slow progress of labour, and failure to initiate labour. Remodelling increases intercellular coupling and cellular excitability, which are the main targets of pharmaceutical treatments for uterine contraction disorders. However, the way in which electrical propagation and force development depend on intercellular coupling and cellular excitability is not fully understood. Using a computational myofibre model we study the dependency of electrical propagation and force development on intercellular coupling and cellular excitability. This model reveals that intercellular coupling determines the conduction velocity. Moreover, our model shows that intercellular coupling alone does not regulate force development. Further, cellular excitability controls whether conduction across the cells is blocked. Lastly, our model describes how cellular excitability regulates force development. Our results bridge cellular factors, targeted by drugs to regulate uterine contractions, and tissue level electromechanical properties, which are responsible for delivery. They are a step forward towards understanding uterine excitation-contraction dynamics and developing safer and more efficient pharmaceutical treatments for uterine contraction disorders.

Bishop scoring: Perceived benefits of using in labour induction by Turkish midwives

It is not always possible to achieve a successful induction. Bishop scoring system is an efficient method used in determining whether the induction will be effective or not. The aim of this study was to train midwives on the benefits and use of the Bishop scoring system and to minimize the unnecessary use of induction. This study was conducted as pretest-posttest quasi-experimental design. This study was conducted in a maternity hospital in Erzurum between 01 February and 31 July 2012. In the study, the midwives received training on the use of the Bishop scoring system, and changes in their knowledge levels and application during practice of induction were then evaluated. While only 20% of midwives were using the Bishop score before the training, 56.7% started to use this tool after the training. Comparing the examinations performed on pregnant women by the midwives in the pre-induction period before and after the training, the mean of the Bishop score changed from 7.26 to 9.68 after the training. It was determined that the training could increase the knowledge levels of midwives regarding the Bishop scoring system and their attention paid to the Bishop scoring system in the practice of induction.

Early amniotomy after vaginal misoprostol for induction of labor: a randomized clinical trial

OBJECTIVES

To test the effectiveness and safety of early amniotomy after vaginal misoprostol for the induction of labor.

STUDY DESIGN

A randomized clinical trial that included 320 women with medical or obstetric indication for labor induction. They were randomly assigned into two equal groups, amniotomy group and control group. Each participant received vaginal misoprostol 50 μg every 6 h for induction of labor. In amniotomy group, amniotomy was done in the early active phase of labor while in the control group, the membranes were left to rupture spontaneously or as judged by the senior resident in the duty.

RESULTS

More subjects in the amniotomy group achieved vaginal delivery within 24 h than in the control group [117 (73.13 %) vs. 105 (65.63 %)]. Subjects in the amniotomy group reported shorter induction to delivery interval (09.72 ± 4.61 h vs. 13.61 ± 5.61, P = .002), and better neonatal outcome compared to the control group. There were no statistically significant differences between both group with regard to number of doses of misoprostol, need for oxytocin, Cesarean Section indication and maternal side effects.

CONCLUSION

Early amniotomy after vaginal misoprostol for labor induction is associated with higher successful vaginal delivery rate, shorter labor duration and better neonatal outcome.

Effects of intravaginally inserted controlled-release dinoprostone and oxytocin for labor induction on umbilical cord blood gas parameters

OBJECTIVE

To compare the effects of oxytocin and dinoprostone used in labor induction on fetal blood gas parameters.

MATERIAL AND METHODS

This prospective randomized trial involved 108 women who completed 37 gestational weeks and who required labor induction prior to normal vaginal birth. Labor was induced in 57 women with an intravenous low dose oxytocin regimen and in 51 with intravaginal dinoprostone (PGE2). Following childbirth, umbilical artery blood gas was analyzed, with pH, pCO2, pO2, HCO3 and base excess (BE) compared in the two groups.

RESULTS

Mean age and obstetrical data (gravidity, parity, gestational weeks and birthweight) were similar in the two groups (p>0.05). All infants had 1 and 5 minute APGAR scores ≥7. Umbilical artery blood pH was similar in the oxytocin and dinoprostone groups (7.31±0.07 vs. 7.31±0.05, p=0.780), as were the other blood gas parameters (pCO2, pO2, base excess and HCO3; p>0.05 each).

CONCLUSION

Induction of labor with either oxytocin or dinoprostone in women with uncomplicated term pregnancies had no adverse effects on umbilical artery blood gas parameters.

A randomised controlled trial of low-dose misoprostol and dinoprostone vaginal pessaries for cervical priming

OBJECTIVE

We studied the efficacy of 25-microg misoprostol pessaries as either single or double dose compared with a 3-mg dinoprostone pessary for cervical priming.

DESIGN AND SETTING

A randomised controlled trial in Singapore.

POPULATION

One hundred and seventy-one women with term pregnancies and modified Bishop scores (mBS) < or =6 from 2003 to 2004.

METHOD

Patients were randomised to single misoprostol dose, double misoprostol dose or the current dinoprostone regimen.

MAIN OUTCOME MEASURES

Primary outcome was number of women who achieved favourable mBS >6 or active labour by day 2. Secondary outcomes were time interval from insertion to delivery, cardiotocographic abnormalities, delivery and neonatal outcome.

RESULTS

More women in the misoprostol double-dose group (96.6%) and dinoprostone group (93%) achieved the primary outcome compared with the single-dose group (77.8%) (P = 0.003 and P = 0.03, respectively). There was no difference in secondary outcomes. More multiparous women achieve primary outcome compared with nulliparous women (odds ratio 0.21, 95% confidence interval 0.06-0.77).

CONCLUSION

Double-dose misoprostol 25 microg is as effective as dinoprostone 3 mg inserts for cervical priming; both are more efficacious than a single-dose misoprostol pessary. Parity prognosticates the success of induction.

Effect of membrane sweeping at term pregnancy on duration of pregnancy and labor induction: a randomized trial

AIM

To evaluate the efficacy of sweeping of fetal membranes for induction of labor in uncomplicated term pregnancies.

METHODS

A randomized controlled trial was performed in 122 pregnant women beyond 39 weeks of gestation with no complications. The women were assigned to have their membranes swept or not (controls) for labor induction. The main outcome measures included duration of pregnancy and possible complications of sweeping of membranes, including rupture of membranes, postpartum infections, and vaginal bleeding.

RESULTS

Twenty-one patients did not give birth in our hospital and were, therefore, excluded from the study; 101 women completed the study (51 patients in the control group and 50 women in the study group). There were no statistically significant differences in maternal age, parity, birth weight, and Bishop score in the two groups. The mean interval between sweeping (stripping) and vaginal examination until delivery was 7.7 +/- (SD) 6.9 and 7.1 +/- 5.6 days in the sweeping and in the control group, respectively (p = 0.61). Of the 101 pregnant women, only 6 patients had premature rupture of membranes (2 in the sweeping group and 4 in the control group). There were no statistically significant differences between these individuals (p = 0.68). Significant vaginal bleeding was not observed in the two groups. Meconium-stained amniotic fluid was seen in 13 women: 8 in the sweeping group and 5 in the control group. There were no statistically significant differences among the women who had meconium-stained fluid in case and control groups (p = 0.39). There were no differences between women who had puerperal fever (3 in the sweeping group and 2 in the control group; p = 0.68). 12 of the 101 women (6 in each group) had cesarean section performed, but there was no difference between the two groups.

CONCLUSION

Sweeping of membranes at 39 weeks of gestation has no significant clinical effect on the duration of pregnancy.

Obstetric "conveniences": elective induction of labor, cesarean birth on demand, and other potentially unnecessary interventions

Common obstetric interventions are often for "convenience" rather than for clinical indications. Before proceeding, it should be clear who is the beneficiary of the convenience. The primary healthcare provider must make sure that women and their partners have a full understanding of what is known about the associated risks, benefits, and alternative approaches of the proposed intervention. Thorough and accurate information allows women to choose what is best for them and their infant on the basis of the individual clinical situation. Ideally, this discussion takes place during the prenatal period when there is ample opportunity to ask questions, reflect on the potential implications, and confer with partners and family members. A review of common obstetric interventions is provided. While these interventions often are medically indicated for the well-being of mothers and infants, the evidence supporting their benefits when used electively is controversial.

Trends and Issues in Labor Induction in the United States: Implications for Clinical Practice

The labor induction rate is at an all-time high in the United States. Although induction of labor is recommended as a therapeutic option only when the benefits of expeditious birth outweigh the risks of continuing the pregnancy, a "psychosocial indication" has become a common rationale for elective induction in the United States. It is unlikely that all women are provided with a complete discussion of the cascade of interventions that frequently accompany labor induction and the risks of cesarean birth. Although at first glance elective labor induction may seem more convenient, an appreciation of the inconvenience of the greater rates of interventions, the longer labor and overall hospital stay, the higher costs, the additional attention required by the primary health care provider when complications occur, and the risk of an adverse outcome for a mother or baby after an elective procedure with subsequent litigation should cause everyone to exercise caution and reevaluate current practice. Professional organizations should take proactive steps to advocate for pregnant women so they are fully aware of the risks and benefits. A public campaign to discourage elective labor induction for nulliparous women is worth serious consideration.

Prediction of adverse outcome associated with vaginal misoprostol for labor induction

OBJECTIVE

To identify predictors of adverse outcome in pregnant women at term receiving 50 microg of intravaginal misoprostol for labor induction.

STUDY DESIGN

A prospective observational study was conducted of 720 pregnant women at term with an unfavorable cervix and a medical or obstetric indication for labor induction. All patients received 50 microg of intravaginal misoprostol every 4h up to three doses. The primary outcome measure was "adverse outcome" defined as: neonatal death, fetal acidemia and emergent cesarean delivery performed for non-reassuring fetal heart rate tracings. A stepwise logistic regression analysis was used to identify predictors of adverse outcome.

RESULTS

Tachysystole (frequent uterine contractions) (odds ratio (OR), 3.7; 95% confidence interval (CI), 1.2-10.8) and fetal tachycardia (OR, 4.8; 95% CI, 1.4-16.2) were determined as significant predictors of adverse outcome. The specificity of the model was 94.2%, whereas the sensitivity was 20.4%.

CONCLUSION

In the absence of tachysystole and fetal tachycardia, an uneventful delivery might be expected for women receiving 50 microg of intravaginal misoprostol.