Is Low Amniotic Fluid Reason to Induce?

It seems that lately I have had more than a few clients who were induced due to low amniotic fluid levels.  I honestly didn’t know much about this particular topic and thought I’d dig up some info.  I was curious what the implications were for mother and baby if the pregnancy continued with low fluid levels and if the pregnancy is healthy and normal in every other category is induction really necessary?  Here is what I discovered:

Oligohydramnios, low amniotic fluid, is usually a cause for induction the U.S.  In fact, 95% of doctors feel that low fluid in an otherwise healthy pregnancy is enough cause to warrant an induction at 40-weeks.

Amniotic fluid levels increase throughout pregnancy until 34-36 weeks and are dependent upon mom staying hydrated.  Because of hydration, there is higher incidence of low amniotic fluid levels in the summer months.  However, if an expecting mother drinks a minimum of 2.5 liters of water a day, her amniotic fluid levels will rise.  After 36 weeks, the fluid levels will start to decrease as the baby grows larger and swallows more and more fluid, especially with a post-term baby.  Within 14 days of labor, the baby urinates less also resulting in lower amniotic fluid levels.

There is very little evidence supporting that induction is necessary for a healthy pregnancy with low amniotic fluid levels.

“In 2009, 91% of physicians believed that isolated oligohydramnios, or low amniotic fluid in an otherwise healthy pregnancy at term, was a risk factor for poor outcomes (Schwartz, Sweeting et al. 2009).

 

However, this belief is not accurate. In early studies on amniotic fluid and outcomes, researchers included babies with congenital defects , women with pre-eclampsia or intrauterine growth restriction (IUGR), and women who were post-term (past 42 weeks) in their samples. These women and babies are more likely to have low amniotic fluid, and they are also much more likely to have poor outcomes. So although early researchers found that babies born to women with low amniotic fluid had higher perinatal mortality rates (Chamberlain, Manning et al. 1984), higher Cesarean rates for fetal distress, and lower Apgar scores (Chauhan, Sanderson et al. 1999), the poor outcomes were due to the complications—not the low amniotic fluid (Gilbert 2012).”

 

If you are told your fluid levels are low and it is time to induce, weigh the pros and cons with your care provider.  As we know, inductions can, at times, lead to less than optimal outcomes and can increase the risk of cesarean section.  The evidence really is not there to support an induction if the mother and baby are doing well and the pregnancy is health and normal otherwise.

“There is no evidence that inducing labor for isolated oligohydramnios at term has any beneficial impact on mother or infant outcomes. Based on the lack of evidence, any recommendation for induction for isolated oligohydramnios at term would be a weak recommendation based on clinical opinion alone.” (Science & Sensibility 2012)

 

Read more about how amniotic fluid levels are measured.