Increased rates of chorioamnionitis with extra-amniotic saline infusion method of labor induction

Foley catheter versus intra-vaginal misoprostol for induction of labor in post-term gestations

OBJECTIVE

To investigate whether a fluid filled intra-uterine extra-amniotic Foley catheter is an effective alternative to vaginal misoprostol in inducing labor in primigravid women with post-term gestations.

PATIENTS AND METHODS

A prospective quasi-randomized controlled trial was designed and 100 primigravid women with post-term gestations were enrolled and equally allocated into two groups. A fluid filled intra-uterine extra-amniotic Foley catheter was inserted in women of group I. Women in group II received 25 microgram misoprostol vaginally every 4 h. Artificial rupture of membranes was performed for all women when their cervices reached 3-4 cm dilatation followed by oxytocin infusion if needed. The main primary outcome parameter was the induction to delivery interval. Results were tabulated and statistically analyzed.

RESULTS

No significant difference was noted in any of the demographic data between both groups. The induction to delivery interval was shorter in the Foley group (897.36 ± 116.0 vs. 960.98 ± 94.18 min; P = 0.003). There were 34 cases which needed oxytocin augmentation in group I compared to 11 cases in group II (P < 0.01). Abnormal uterine activity occurred in three cases in the misoprostol group, but none in the Foley group. Ominous fetal heart rate was noted in one case in group I but three in group II.

CONCLUSION

Fluid filled Foley catheter seems to be superior to 25 μg vaginal misoprostol regimen, when used to induce labor in primigravidae with post-term gestations with the advantage of having a shorter induction delivery interval, but more need for oxytocin augmentation.

Histologic chorioamnionitis is more common after spontaneous labor than after induced labor at term

OBJECTIVE

Inflammation of the chorioamniotic membranes (histologic chorioamnionitis) is a risk factor for adverse neonatal outcome. Labor has many common features with inflammatory processes; therefore, an important question is whether the frequency of histologic chorioamnionitis in spontaneous labor at term is higher than that of women in labor after induction. This study was conducted to address this question.

STUDY DESIGN

The frequency of histologic chorioamnionitis was compared between patients who delivered after the spontaneous onset of labor versus those who delivered after induction of labor at term in singleton gestations (> or = 37 weeks). Patients in whom uterotonic agents were used during the latent phase of labor were excluded.

RESULTS

(1) The overall frequency of histologic chorioamnionitis was 20.2% (107/531); (2) histologic chorioamnionitis was significantly more frequent in women who delivered after the spontaneous onset of labor than in those who underwent induction of labor (24.3% [81/333] versus 13.1% [26/198], p < 0.005). This difference remained significant after adjusting for parity, gestational age at delivery, total duration of labor, the interval from rupture of membranes to delivery and the mode of delivery.

CONCLUSION

Histologic chorioamnionitis is more common in women who delivered after the spontaneous onset of labor than in those who underwent induction of labor at term.

Induction of labor using a foley balloon, with and without extra-amniotic saline infusion

OBJECTIVE

To compare transcervical Foley bulb with and without extra-amniotic saline infusion for induction of labor in patients with an unfavorable cervix.

METHODS

Women who presented for induction of labor with Bishop score less than 5 were randomly assigned to receive Foley alone or Foley with extra-amniotic saline infusion for induction of labor. Primary outcome was time from start of induction to vaginal delivery. Secondary outcomes were cesarean delivery rates, incidence of chorioamnionitis, Apgar scores at 1 and 5 minutes, and adverse events.

RESULTS

One hundred forty women completed the study. Time from induction to vaginal delivery was 16.58 (+/- 7.55) hours in the extra-amniotic saline infusion group compared with 21.47 (+/- 9.95) hours in the Foley group (P < .01). Chorioamnionitis occurred in 4 of 66 (6.1%) women in the extra-amniotic saline infusion group compared with 12 of 74 (16.2%) women in the Foley group (P = .067). Cesarean delivery rate was 21.2% versus 20.1% in the extra-amniotic saline infusion and Foley groups, respectively (P = 1.0). Median 1-minute and 5-minute Apgar scores were 9 in both groups. Adverse events were rare and unrelated to method of induction.

CONCLUSION

Induction of labor by using Foley with extra-amniotic saline infusion results in shorter induction-to-vaginal-delivery time than Foley alone, without affecting cesarean delivery rates.

LEVEL OF EVIDENCE

II-I