Effects of preeclampsia on labor induction with prostaglandin E2 and oxytocin

Park, Kyo Hoon; Cho, Yong Kyoon; Choi, Hoon; Rin Kim, Bok; Han, Sung Shik; Lee, Chul Min; Lee, Hong Kyoon

Abstract

OBJECTIVE
The purposes of this study were 1) to determine whether preeclampsia itself affects failure of labor induction with prostaglandin E2 and oxytocin and 2) to investigate risk factors for failed induction in women with preeclampsia. METHOD: Fifty preeclamptic women and 175 nonpreeclamptic women requiring labor induction were studied prospectively. Intravaginal prostaglandin (PG) E2 tablet (Dinoprostone, The Upjohn company, 3 mg) followed by a second dose if the cervix assessed 6 hours later was 5 or less of Bishop score, and oxytocin were used for labor induction. Women with rupture of membrane, spontaneous contraction resulting in cervical change or an initial cervical examination showing more than 2 cm dilatation and 50% effacement were excluded. Statistics were analyzed with 2 test, Student t test, and multiple logistic regression.
RESULTS
1) The women with preeclampsia had a significantly higher rate of failed induction than did those without preeclampsia [24% (2/50) versus 9% (16/175); p <0.05]. However, the women with preeclampsia had a higher rate of the use of magnesium sulfate, and were more likely to decrease gestational age at induction and increase maternal weight than those without preeclamp sia (p <0.0001, respectively). There were no significant differences in prevalence of nulliparity and low initial Bishop score (< or =3) between the women with and without preeclampsia. 2) Multiple logistic regression showed that preeclampsia itself was not associated with failed induction after correction of known confounding variables (odds ratio 0.22, 95% confidence interval 0.03-2). 3) In women with preeclampsia, the use of magnesium sulfate only was associated with increased risk of failed induction analyzed by multiple logistic regression(odds ratio 38.5, 95% confidence interval 1.6-897). Maternal weight with 70 kg or more was associated with increased risk of failed induction, but it is not statistically significant (p=0.055).
CONCLUSIONS
1) The risk of failed induction is increased in women with preeclampsia, but not by preeclampsia itself but by the use of magnesium sulfate, prematurity, and increased maternal weight secondary to preeclampsia. 2) The use of magnesium sulfate is independent risk factor for failed induction in women with preeclampsia.