Induction at 41 weeks – ! What’s it all about

By April 23, 2014Pregnancy

There are all kinds of problems associated with providing care based on risk rather than on individual women. However, risk along with ‘due dates’ is here to stay, and women often want to know about risks. Risk is a very personal concept and different women will consider different risks to be significant to them. Everything we do in life involves risk. So when considering whether to do X or Y there is no ‘risk free’ option. All women can do is choose the option with the risks they are most willing to take. However, in order to make a decision women need adequate information about the risks involved in each option. If a health care provider fails to provide adequate information they could be faced with legal action.  Induction for prolonged pregnancy is not right or wrong if the choice is made by a woman who has an understanding of all the options and associated risks.  As a doula and  midwife’s assistant,  I am ‘with woman’ regardless of her choices. It is my job to share information and support decisions – not to judge. 

birthWhat is a prolonged pregnancy?

Before we go any further here are some definitions for clarity:

§  Term (as in a ‘normal’ and healthy gestation period): is from 37 weeks to 42 weeks.

§  Post dates: the pregnancy has continued beyond the decided due date ie. is over 40 weeks.

§  Post term: the pregnancy has continued beyond term ie. 42+ weeks.

The World Health Organization’s definition of a ‘prolonged pregnancy’ is one that has continued beyond 42 weeks ie. is post term. I am pretty sure that this was not the definition used when collecting the above induction rate statistics because most hospitals have a policy of induction at 41 weeks which is before a prolonged pregnancy has occurred. Very few women experience a prolonged pregnancy.

The baby and placenta signal to the mother’s body that baby is mature and ready to be born (Mendelson 2009) – this starts the complex cascade of physical changes that results in the labor process.

How long it takes for an individual baby to become mature varies.  In theory after term ie. 42 weeks the placenta starts to shut down. There is no evidence to support this notion.  There is good physiological explanation of the development and ageing of the placenta which concludes that: “There is, in fact, no logical reason for believing that the placenta, which is a fetal organ, should age while the other fetal organs do not,”There have been signs of placental shut down (ie. calcification) in placentas at 37 weeks and big juicy healthy placentas at 43 weeks. There is also the idea that the baby will grow huge and therefore birth with difficultly. Again there is no evidence to support this theory and babies are pretty good at finding their way out of their mothers expandable pelvis.

Reviews can only be as good as the research they review and there are some concerns about the quality of the research. The World Health Organization recommends induction after 41 weeks based on this review but acknowledges the evidence is “low-quality evidence. Weak recommendation”. You can find further critical analysis of the data here.

The induction process is a fairly invasive procedure which usually involves some or all of the following (you can read more about the process of induction here). There are a number of minor side effects associated with these medications/procedures (eg. nausea, discomfort etc.) There are also some major risks:

Prostaglandins (prostin E2 or cervidil) to ripen the cervix: hyperstimulation resulting in fetal distress and c-section.

Rupturing the membranes: fetal distress and c-section

IV syntocinon / pitocin: Mother – rupture of uterus; post partum hemorrhage; water intoxication leading to convulsions, coma and/or death. Baby – hypoxic brain damage; neonatal jaundice; neonatal retinal haemorrhage; death. There is also research suggesting that there may be a link between the use of syntocinon/pitocin for induction and ADHD (Gregory et al. 2013Kurth & Haussmann 2011)

The most extreme of these risks are rare but fetal distress and c-section are fairly common.

The potential effects of uterine hyperstimulation on the baby are well known (Simpson & James 2008)- which is why continuous fetal monitoring is recommended during induction.  This limiting mother’s movement  in assisting as baby moves through down the birth path.  This may also explain the association between induction and cerebral palsy (Elkamil et al. 2010)

So, once again the Cochrane review states:“Women’s experiences and opinions about these choices have not been adequately evaluated.”This is becoming a theme across Cochrane reviews. However, one thing is certain – choosing induction will totally alter your birth experience and the options open to you. Women need to know that agreeing to induction means agreeing to continuous monitoring and an IV drip, which will limit movement. Induced contractions are usually more painful than natural contractions and the inability to move and/or use warm water (shower or bath) reduces the ability to cope. The result is that an epidural may be needed. An induced birth is not a physiological birth and requires monitoring (vaginal exams) and time frames. Basically you have bought a ticket on the intervention rollercoaster.

For many women this is fine and worth the risk, but I encounter too many women who are unprepared for the level of intervention required during an induction.

In Summary

A significant minority of babies will not be born by 41 weeks gestation. While the definition of a prolonged pregnancy is 42 weeks+, induction is usually suggested during the 41st week. Women need to be given adequate information about the risks and benefits involved with either waiting or inducing in order to make the choice that is right for them. There is no risk free option. The risk of perinatal death is extremely small for both options. I know women who have lost a baby in the 41st week of pregnancy, and women who have lost a baby as a result of the induction process. For first time mothers the induction process poses particular risks for themselves and their babies. Each individual woman must decide which set of risks she is most willing to take – and be supported in her choice.

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