A randomized controlled trial of foley catheter, extra-amniotic saline infusion and prostaglandin e2 suppository for labor induction

OBJECTIVE

The aim of this study is to further compare the efficacy of PGE2 suppository, the intracervical foley catheter and extra-amniotic saline infusion in nulliparous women referred for labor induction.

MATERIALS AND METHODS

Totally 368 nulliparous women with a Bishop score ≤ 4 with singleton gestation, vertex presentation and intact membrane referred for labor induction were randomly assigned to 3 groups; Foley catheter alone, Extra-amniotic saline infusion (EASI) and PGE2 suppository. All women received concurrent dilute oxytocine infusion. The change in the Bishop Score, labor progress, various labor endpoints and outcomes of labor were assessed.

RESULTS

From 363 women studied after exclusion of 5, 119 were assigned to EASI, 121 to Foley and 118 to PGE2. Patients' demographics did not differ significantly between three groups nor did indication for induction (P = 0.0001). The EASI group had a significant improvement in Bishop Score 6 hours after induction. The mean time to active phase was 357±135min for EASI,457±178 for Foley and 609±238 min for PGE2 group respectively (P < 0.05).rate of spontaneous rupture of membranes was higher in the EASI group (P = 0.0001) and the mean time from the start of induction up to spontaneous rupture of membranes in the EASI group was shorter than other group(P < 0.05). The mean time to vaginal delivery was 14.8±6.1 in EASI group,11.4±4.8 in Foley and 18.9±6.4 in PGE2 group(P < 0.05).there were no differences in Apgar scores, mean neonatal birth weight and neonatal morbidity.

CONCLUSION

Our study showed that pre-induction cervical ripening by EASI with concurrent oxytocin is better than Foley and PGE2 in Bishop score and various labor end point and outcomes.

Clinical parameters for prediction of successful labor induction after application of intravaginal dinoprostone in nulliparous Chinese women

BACKGROUND

The aim of this study was to compare the possible clinical parameters for prediction of successful labor induction in Chinese nulliparous women.

MATERIAL/METHODS

A retrospective, observational trial of labor induction was performed, using a single dose of 10 mg controlled-release dinoprostone for preinduction cervical ripening in 127 nulliparous women (gestational age 38-42 weeks, singleton cephalic presentation). The characteristics of the women with successful labor induction (defined as vaginal delivery achieved on the day of admission; n=80) and failed labor induction (n=47) were compared.

RESULTS

The main differences observed between the groups were gravidity (P<0.05), induction-active labor interval (5.16±2.98 vs. 8.40±3.41; P<0.05) and birth weight (3421.11±368.14 vs. 3566.36±345.16; P<0.05). Logistic regression demonstrated that gravidity (P<0.05) and induction-active labor interval (P<0.05), but not Bishop score, were significant and independent contributing factors for successful labor induction. In the receiver operating characteristic curves for the prediction of successful labor induction, the best cut-off value for gravidity was 3 (95% confidence interval [CI] 0.64-0.83, P=0.000), and the best cut-off value for the induction-active labor interval was 7.96 (95%CI 0.66-0.85, P=0.000).

CONCLUSIONS

Less gravidity and shorter induction-active labor interval predict successful labor induction with reasonable accuracy.

Induction of labor in a contemporary obstetric cohort

OBJECTIVE

We sought to describe details of labor induction, including precursors and methods, and associated vaginal delivery rates.

STUDY DESIGN

This was a retrospective cohort study of 208,695 electronic medical records from 19 hospitals across the United States, 2002 through 2008.

RESULTS

Induction occurred in 42.9% of nulliparas and 31.8% of multiparas and elective or no recorded indication for induction at term occurred in 35.5% and 44.1%, respectively. Elective induction at term in multiparas was highly successful (vaginal delivery 97%) compared to nulliparas (76.2%). For all precursors, cesarean delivery was more common in nulliparas in the latent compared to active phase of labor. Regardless of method, vaginal delivery rates were higher with a ripe vs unripe cervix, particularly for multiparas (86.6-100%).

CONCLUSION

Induction of labor was a common obstetric intervention. Selecting appropriate candidates and waiting longer for labor to progress into the active phase would make an impact on decreasing the national cesarean delivery rate.

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.

Randomized clinical trial evaluating the frequency of membrane sweeping with an unfavorable cervix at 39 weeks

BACKGROUND

Despite the widely accepted use of membrane sweeping to prevent postmaturity pregnancies, the optimal frequency for this procedure has not been established.

AIM

To determine if the frequency of membrane sweeping in women with an unfavorable cervix at term results in fewer labor inductions.

METHODS

This was a randomized trial of women with an unfavorable cervix (Bishop's score of ≤4) at 39 weeks randomized into three groups: control, once-weekly membrane sweeping, and twice-weekly membrane sweeping.

RESULTS

Between January 2005 and June 2008, 350 women were randomized into the study (groups: control [n = 116], once weekly [n = 117], and twice weekly [n = 117]). Randomization of Bishop's score was different between groups (P = 0.019), with 67%, 71%, and 83% of control, once-, and twice-weekly groups, respectively, having scores of 3-4. There was no difference in the unadjusted rate of labor induction between the groups (35% versus 27% versus 23%, P = 0.149), and after the adjustment for the randomization of Bishop's score (adjusted odds ratio [OR] = 0.73, 95% confidence interval [CI] 0.41-1.29 and OR = 0.65, 95% CI 0.36-1.18 for once- and twice-weekly groups, respectively). A Bishop's score of 3-4 at randomization was the only statistically significant factor that decreased the likelihood of induction at 41 weeks (OR = 0.42, 95% CI 0.25-0.69).

CONCLUSION

Frequency of membrane sweeping does not influence the likelihood of remaining undelivered at 41 weeks of pregnancy. The Bishop's score at around 39 weeks is the important factor as a predictor of the duration of pregnancy, and further studies would be required to determine whether membrane sweeping influences pregnancy duration.

Transvaginal ultrasonographic cervical measurement in predicting failed labor induction and cesarean delivery for failure to progress in nulliparous women

The aim of this study was to evaluate the value of transvaginal sonographic cervical measurement in predicting failed labor induction and cesarean delivery for failure to progress in nulliparous women. One hundred and sixty-one women scheduled for labor induction underwent transvaginal ultrasonography and digital cervical examinations. Logistic regression demonstrated that cervical length and gestational age at induction, but not the Bishop score, significantly and independently predicted failed labor induction. According to the receiver operating characteristic curves analysis, the best cut-off value of cervical length for predicting failed labor induction was 28 mm, with a sensitivity of 62% and a specificity of 60%. In terms of the likelihood of a cesarean delivery for failure to progress as the outcome variable, logistic regression indicated that maternal height and birth weight, but not cervical length or Bishop score, were significantly and independently associated with an increased risk of cesarean delivery for failure to progress. Transvaginal sonographic measurements of cervical length thus independently predicted failed labor induction in nulliparous women. However, the relatively poor predictive performance of this test undermines its clinical usefulness as a predictor of failed labor induction. Moreover, cervical length appears to have a poor predictive value for the likelihood of a cesarean delivery for failure to progress.

A preventive approach to obstetric care in a rural hospital: association between higher rates of preventive labor induction and lower rates of cesarean delivery

PURPOSE

Annual cesarean delivery rates in North America are increasing. Despite the morbidity associated with cesarean delivery, a safe preventive strategy to reduce the use of this procedure has not been forthcoming. During the 1990s, clinicians in a rural hospital developed a method of care involving prostaglandin-assisted preventive labor induction. An inverse relationship was noted between yearly hospital rates of labor induction and cesarean delivery. The purpose of our study was to compare cesarean delivery rates between practitioners who often used preventive induction and practitioners who did not, while controlling for patient mix and differences in practice style.

METHODS

Between 1993 and 1997, different hospital practitioners used risk-guided prostaglandin-assisted preventive labor induction with differing intensity. We used a retrospective cohort design, based on the practitioner providing prenatal care, to compare birth outcomes in women exposed to this alternative method of care with those in women not exposed. Multiple logistic regression analysis controlled for patient characteristics and clustering by practitioner.

RESULTS

The exposed group (n = 794), as compared with the nonexposed group (n = 1,075), had a higher labor induction rate (31.4% vs 20.4%, P <.001), a greater use of prostaglandin E2 (23.3% vs 15.7%, P <.001), and a lower cesarean delivery rate (5.3% vs 11.8%, P <.001). Adjustment for cluster effects, patient characteristics, and the use of epidural analgesia did not eliminate the significant association between exposure to this preventive method of care and a lower cesarean delivery rate. Rates of other adverse birth outcomes were either unchanged or reduced in the exposed group.

CONCLUSIONS

A preventive approach to reducing cesarean deliveries may be possible. This study found that practitioners who often used risk-guided, prostaglandin-assisted labor induction had a lower cesarean delivery rate without increases in rates of other adverse birth outcomes. Randomized controlled trials of this method of care are warranted.

Step 6: does not routinely employ practices, procedures unsupported by scientific evidence: the coalition for improving maternity services:

Step 6 of the Ten Steps of Mother-Friendly Care addresses two issues: 1) the routine use of interventions (shaving, enemas, intravenous drips, withholding food and fluids, early rupture of membranes, and continuous electronic fetal monitoring; and 2) the optimal rates of induction, episiotomy, cesareans, and vaginal births after cesarean. Rationales for compliance and systematic reviews are presented.

Research summaries for normal birth

In this column, the author presents summaries of four research studies that further support the benefits of normal birth. The topics of the studies address midwifery care practices, labor induction and increased medical costs, vaginal birth after cesarean, and labor support from student nurse-doulas.

Misoprostol-is more research needed?

Misoprostol (Cytotec) is a synthetic prostaglandin E1 analogue that was designed for the prevention and treatment of peptic ulcer associated with the use of nonsteroidal anti-inflammatory drugs. In obstetrics, misoprostol has been administered for induction of first and second trimester abortion, for induction of labor in the third trimester, and to control postpartum hemorrhage. None of these uses has been approved by the Food and Drug Administration. Nevertheless, misoprostol is widely used in the United States and throughout the world. Advantages are cited as reduced rate of cesareans, shorter time from induction to birth and, particularly in developing countries, lower cost, oral, vaginal or rectal administration, and stability without refrigeration. Disadvantages are uterine hyperstimulation and, in rare instances, uterine rupture and death. Mothers should be informed of both the risks and the possible benefits of misoprostol. Further research with large samples is necessary to determine whether the risks outweigh any possible benefits.