Preinduction cervical ripening with commercially available prostaglandin E2 gel: a randomized, double-blind comparison with a hospital-compounded preparation

Intracervical prostaglandins for induction of labour

BACKGROUND

Prostaglandins have been used for cervical ripening and induction of labour since the 1970s. The goal of the administration of prostaglandins in the process of induction of labour is to achieve cervical ripening before the onset of contractions. One of the routes of administration that was proposed is intracervical. Using this route, prostaglandins are less easy to administer and the need for exposing the cervix may cause discomfort to the woman.

OBJECTIVES

To determine the effects of intracervical prostaglandins for third trimester cervical ripening or induction of labour compared with placebo/no treatment and with vaginal prostaglandins (except misoprostol).

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (August 2007) and bibliographies of relevant papers.

SELECTION CRITERIA

Clinical trials comparing intracervical prostaglandins used for third trimester cervical ripening or labour induction with placebo/no treatment or other methods listed above it on a predefined list of labour induction methods (vaginal prostaglandins, except misoprostol).

DATA COLLECTION AND ANALYSIS

A strategy was developed to deal with the large volume and complexity of trial data relating to labour induction. This involved a two-stage method of data extraction.

MAIN RESULTS

Fifty-six trials (7738 women) are included. INTRACERVICAL PGE2 WITH PLACEBO/NO TREATMENT: 28 TRIALS, 3764 WOMEN: Four studies reported the number of women who did not achieve vaginal delivery within 24 hours, showing a decreased risk with PGE2 (relative risk (RR) 0.61; 95% confidence interval (CI) 0.47 to 0.79). There was a small, and statistically non-significant, reduction of the risk of caesarean section when PGE2 was used (RR 0.88; 95% CI 0.77 to 1.00). The finding was statistically significant in a subgroup of women with intact membranes and unfavourable cervix only (RR 0.82; 95% CI 0.68 to 0.98). The risk of hyperstimulation with fetal heart rate (FHR) changes was not significantly increased (RR 1.21; 95% CI 0.72 to 2.05). However, the risk of hyperstimulation without FHR changes was significantly increased (RR 1.59; 95% CI 1.09 to 2.33. INTRACERVICAL PGE2 WITH INTRAVAGINAL PGE2: 29 TRIALS, 3881 WOMEN: The risk of not achieving vaginal delivery within 24 hours was increased with intracervical PGE2 (RR 1.26; 95% CI 1.12 to 1.41). There was no change in the risk of caesarean section (RR 1.07; 95% CI 0.93 to 1.22). The risks of hyperstimulation with FHR changes (RR 0.76; 95% CI 0.39 to 1.49) and without FHR changes (RR 0.80; 95% CI 0.56 to 1.15) were non-significantly different with the two methods of PGE2 administration. Only one trial with small sample size reported on women's views, with no difference between groups. INTRACERVICAL PGE2 LOW DOSE WITH INTRACERVICAL PGE2 HIGH DOSE: TWO TRIALS, 102 WOMEN: The trials are too small to provide any useful information.

AUTHORS' CONCLUSIONS

Intracervical prostaglandins are effective compared to placebo, but appear inferior when compared to intravaginal prostaglandins.

Natural Prostaglandins for Induction of Labor and Preinduction Cervical Ripening

Prostaglandin (PG) E2 has superseded all other natural prostaglandins for induction of labor and pre-induction cervical ripening. This evolution and its rationale are briefly described. PGE2 has been administered intravenously, orally, vaginally, endocervically, and extra-amniotically for induction of labor. All of these, except the intravenous route, have also been explored for pre-induction cervical ripening. The distinction between formal induction and pre-induction is not always clearly made with many studies pursuing both goals at once. Nevertheless, the effectiveness of PGE2 to achieve ripening and induction is currently beyond doubt. In women with unfavorable induction prospects PGE2 results in lower rates of failed induction and higher rates of delivery within a reasonable interval than amniotomy and/or oxytocin. This also applies to women with prelabor rupture of the membranes, but the relative advantages of PGE2 over traditional methods are less clear for women with a favorable cervix. Vaginal administration of PGE2 has superseded virtually all other routes of PGE2 administration except the endocervical route, which tends to give variable results depending on spillage from the endocervical canal. Doses and formulations of vaginal PGE2 with various gels, tablets, pessaries and slow release inserts have varied widely and continue to do so. There is currently no evidence for the superiority of one PGE2 preparation over another.

Induction of labor

The rate of labor induction continues to rise significantly in the United States because of a growing use of labor induction for postterm pregnancies and elective induction of labor. Although different types and doses of prostaglandins used for cervical ripening often initiate uterine activity, the principal role of these agents is to soften the unripe cervix independent of uterine activity. Several systematic reviews with meta-analyses have shown that prostaglandins are superior to placebo and oxytocin alone in ripening of the cervix. Numerous studies and meta-analyses have assessed misoprostol's efficacy and safety as a labor induction agent. The most appropriate dose and route of administration has not yet been confirmed.

Cervical ripening and induction of labor with misoprostol, dinoprostone gel, and a Foley catheter: a randomized trial of 3 techniques

OBJECTIVE

The purpose of this study was to compare the efficacy of 3 different techniques of cervical ripening and induction.

STUDY DESIGN

Patients who required cervical ripening and induction were randomized to one of 3 groups: (1) supracervical Foley catheter and intravaginal dinoprostone gel, (2) supracervical Foley catheter and 100 microg oral doses of misoprostol, or (3) serial 100-microg oral doses of misoprostol. Intravenous oxytocin was administered when a protraction disorder of labor was identified.

RESULTS

There were 339 women randomized. There was no significant difference in the time from first intervention to delivery in the 3 groups (P =.546). In each group, a similar percentage of women required oxytocin (P =.103). The rates of cesarean delivery were equivalent among the groups (P =.722). Rates of tachysystole were high but statistically equivalent among the 3 groups. There were no significant differences in Apgar scores or umbilical artery pH.

CONCLUSION

Oral 100 microg serial doses of misoprostol, with or without the use of a supracervical Foley catheter, were equivalent to the use of a supracervical Foley catheter and serial 4-mg doses of dinoprostone gel for cervical ripening and the induction of labor.

Second-trimester maternal serum alpha-fetoprotein (MSAFP) is elevated in women with adverse pregnancy outcome associated with inherited thrombophilias

Obstetric complications, such as severe pre-eclampsia, fetal growth restriction, abruptio placentae, or stillbirth are associated with abnormally elevated second-trimester maternal serum alpha-fetoprotein (MSAFP) and beta subunit of human chorionic gonadotrophin (betahCG). This has been attributed to placental abnormalities. Women with thrombophilias have been shown to have abnormalities of the placenta resulting in adverse pregnancy outcome in these patients. The purpose of the present study was to evaluate whether women with pregnancy complications and inherited thrombophilias have abnormally elevated second-trimester MSAFP or betahCG. Sixty-two women with pregnancy complications were tested for inherited thrombophilias several months after delivery. The thrombophilia group included 29 women with pregnancy complications and an inherited thrombophilia and the control group included 33 other patients without thrombophilia. Patients in the thrombophilia group had a higher median MoM MSAFP compared to the controls (1.337 vs. 1.086, p=0.0516). The incidence of abnormally elevated MSAFP (>2.5 MoM) was also significantly higher in the thrombophilia group compared to controls (21% vs. 3%, p=0.04). Neither the median MoM betahCG nor the incidence of abnormally elevated betahCG were significantly different between the groups. We conclude that second trimester MSAFP, but not betahCG, is abnormally elevated in patients with thrombophilia and obstetric complications.

The labor-adjusted cesarean section rate--a more informative method than the cesarean section "rate" for assessing a practitioner's labor and delivery skills

OBJECTIVE

Our purpose was to determine the benefits of an acuity-adjusted labor management tool.

STUDY DESIGN

A retrospective review was performed of all deliveries at Good Samaritan Regional Medical Center in Phoenix, Arizona, for a 1-year period from Jan. 1 to Dec. 31, 1994. All physicians with > or = 20 deliveries were included in the analysis. Patients with indications for which most practitioners would perform a cesarean delivery were removed from consideration. Physicians were then compared with respect to labor management in the remaining patients without relative contraindications to vaginal delivery.

RESULTS

The total number of deliveries (n = 6062) was performed by 47 attending obstetricians, 9 perinatologists, an obstetrics-gynecology clinic, and a family practice clinic. The "raw" cesarean section rate was 20.1%. Those at high risk for cesarean delivery (n = 534) were excluded, leaving 684 cesarean sections performed in 5528 patients (12.4%) who were appropriate to labor. Differences were observed between the nulliparous cesarean section rate (16%) compared with that for parous patients (10.1%) (p < 0.0001 by Fisher's exact test (two-tailed) but not between attending obstetrician-gynecologists (12.4%) and perinatologists (13.8%) (not significant).

CONCLUSION

A labor-adjusted cesarean section rate is more appropriate than just "raw" data. Medical, obstetric, and fetal factors affect a "raw" rate that is out of the control of the obstetrician. This method of assessing the labor and delivery skills of each practitioner and hospital would allow meaningful comparison with others.