03. tbl. 105. árg. 2019

The effects of induced labor at 41 week of pregnancy on mode of delivery and outcome

Áhrif framköllunar fæðingar eftir 41. viku meðgöngu á fæðingarmáta og útkomu fæðinga

Introduction: Rates of induction of labor (IOL) in Iceland and most neighboring countries have increased. Recent literature on IOL provided contradicting effects on mode of delivery, maternal and neonatal outcome.

Material and methods:  The aim of this study was to evaluate the impact of IOL in late term pregnancies (≥41 weeks) on mode of delivery, maternal and neonatal outcome. A retrospective cohort study of deliveries after 41 weeks of pregnancy was conducted for all deliveries in Landspitali in the period 2013-2016, comparing outcomes of IOL deliveries to spontaneous labor deliveries. Logistic regression analysis was performed to determine the impact of the independent variables on the outcome.

Results: Of the 2419 women cohort, 61.8% had a spontaneous onset of labor and 38.2% had IOL. The results show that IOL increases probability of caesarean section in primiparas women (p<0.01). IOL increases the use of epidural anesthesia in labor, both for primiparas (p<0.001) and multiparas (p<0.05). Similar results where observed in the neonatal outcome in both groups. Gestational age increases the probability of instrumental delivery (p<0.05), caesarean section (p<0.01), use of epidural anesthe­sia (p<0.01), Apgar <7 at 5 minutes (p<0.01) and fetal distress (p<0.01).

Conclusion: Induction of labor has some negative impact on maternal outcome but leads at the same time to a shorter preg­nancy, which again decreases negative impact of prolonged pregnancy. It is important to evaluate the advantages and disadvantages of induction of labor before making a decision when to induce labor.


Table I: Descriptive statistic for independent categorical variables by onset of labor.

Table II: Descriptive statistic for independent continuous variables.

Table III: Parameter estimates, standard errors and model statistics for multinomial logit and logit models.

Table IV: Parameter estimates, standard errors and model statistics for logit models.

Table V: Parameter estimates, standard errors and model statistics for ordered logit models.

Table VI: Parameter estimates, standard errors and model statistics for linear regression models.









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