Randomised Controlled Trial of Elective Induction of Labour at 40 and 41 Weeks to Prevent Prolonged Pregnancy

There have been discussions as to the time of elective induction of labour to curb the continuation of pregnancy that might endanger the lives of both the mother and child. This research was conducted to assess foetal and maternal consequences of planned delivery at 40 and 41weeks in women with low-risk singleton pregnancy.

A randomised controlled trial with equal allocation of participants (96 pregnant women in each arm) into 40weeks and 41weeks. Participants were randomised at the antenatal clinic at 39 weeks for induction of labour. The main outcome was the caesarean section rate. Secondary outcomes were maternal (genital tract laceration rate) and foetal (rates of meconium staining of amniotic fluid, SCBU admission, perinatal mortality, birth trauma, birth weight, and neonatal APGAR score at 1 and 5 minutes). Student t-test and chi-square test were used for inter-group comparison.

Incidence of caesarean delivery (26.6% vs. 21.3%; p=0.406), and genital laceration (2.1% vs. 5.6%; p=0.268) did not differ between groups. Significantly higher birth weight was noted among women induced at 41weeks (3.41 ± 0.37kg) than 40weeks (3.28 ± 0.46kg) (p=0.043). Also, there was significant variation in meconium staining of amniotic fluid between 40weeks (11.7%) and 41weeks (25.8%) (p=0.014). Other foetal outcomes showed no significant difference.

Inducing labour at 40weeks is safe for low-risk women as it does not significantly increase the cesarean delivery rate and adverse perinatal outcomes. Therefore, elective induction of labour at 40weeks should be recommended and introduced into obstetric practice without the fear of adverse outcomes.