A post-term pregnancy is one that has done 42 completed weeks from first day of last menstruation . The challenge comes in that a good number of women don ’ t know or can ’ t recall exactly when the last menstruation was .
mother and baby to decide on the plan of action . As many as 80 % of patients who reach 42 weeks ’ gestation have an unfavorable cervical examination . If cervix is favorable or ripe ( ready ) induction is carried on straight away ; if not then the cervix is ripened using certain drugs ( prostaglandins ) taken either vaginally or orally .
Another method for ripening the cervix is by mechanical dilation . These devices may act by a combination of mechanical forces and by causing release of endogenous prostaglandins . Foley balloon catheters placed in the cervix , extra-amniotic saline infusions ( filling sterile saline solution around the sac ), and laminaria ( short reed that expands in contact with water that is placed in the cervix to dilate it ) have all been studied and have been shown to be effective .
In past times , if all is well with both mum and baby the first option could be expectant management i . e . wait for the woman to go into labor spontaneously , however this is practiced in few places today .
Having had said this it is rare that your doctor will intentionally allow a pregnancy to progress so far . Most centers will carry out routine induction of labor at about 41 weeks with variances of 41 + 0-3 days .
Routine induction at 41 weeks of gestation does not increase the cesarean delivery rate and may decrease it without negatively affecting perinatal morbidity or mortality . In fact , both the woman and the neonate benefit from a policy of routine induction of labor in well-dated , lowrisk pregnancies at 41 weeks ’ gestation . Because it is associated with a lower rate of adverse outcomes , including shoulder dystocia and meconium aspiration syndrome , this policy may also prove to be more cost-effective .
If the mother has contraindications to induction of labor such as a placenta previa , previous caesarean section , fetal distress then a caesarean section will be performed .
We should also remember that induction is not without risks such as tachysystole ( overstimulation of the uterus with prolonged and frequent contractions ), fetal distress , infection , failed induction , bleeding after delivery and so on .
All the options are not without risk so a judicious decision must be made with both mother and baby in mind .
Prevention
The mainstay is elective induction of labor at 41 weeks which has been discussed above . Several minimally invasive interventions have been recommended to encourage the onset of labor at term and prevent post-term pregnancy , including membrane stripping , unprotected sexual activity , and acupuncture .
Membrane stripping which involves a vaginal exam with an open cervix and releasing the membranes from the uterine wall may be painful , increase infection rates , induce vaginal bleeding and irregular contractions without reducing the need for labor induction . The other two methods do not have enough literature to support but will harm neither mum nor baby so if they will avert post-term pregnancy they can be considered as interventions .
Summary
The management of post-term pregnancies is complicated and fraught with complex issues . Data support inducing labor at 41 weeks ’ gestation in an accurately dated , low-risk pregnancy , regardless of cervical examination findings . This strategy , although not without its critics , averts the need for serial follow up of the baby and does not increase the cesarean delivery rate ; in fact , it may decrease the cesarean
delivery rate .
Dr . Maureen Owiti is a practicing Obstetrician Gynaecologist and fertility consultant based in Nairobi . You can commune with her on this or related matters via email at : Drmaureenowiti @ gmail . com .