Low amniotic fluid .. is it a real problem?
Over the past 2 years, I am increasingly hearing the diagnosis “oligohydramnios” or “low amniotic fluid” as one of the biggest reasons for induction and/or C-Section. How do we “diagnose” low amniotic fluid? How much is too little? Do we need repeated Ultrasound Scans to determine the level of fluid? What about traditional hands-on skills to validate that most healthy mothers will carry enough fluid for their babies to thrive in the womb?
First things first .. what is amniotic fluid? By the end of pregnancy baby is surrounded by 500-1000 mls of fluid. This is mostly made up of fluid secreted by the amniotic sac (which is a part of baby’s side of the placenta). It then makes sense, that if the mother is healthy, eating and drinking well, her placenta (and thereby the baby’s amniotic sac) will be healthy enough to produce adequate fluid. The other part of this fluid is contributed by the baby. The baby contributes to this fluid by its urinary and respiratory tract secretions – by some accounts, almost to the tune of 500 ml per day! Thus, amniotic fluid is being constantly produced and renewed – mother and baby both contribute to producing the fluid; the baby swallows the fluid (yes it does, from 17 weeks on or thereabouts .. so when your Care Provider says it is time for the baby to be born by induction or C-section because he/she will swallow the fluid, you know that is not a good reason!!) and then it goes through the gut into the baby’s circulation, baby pees, and then it is sent out through the placenta. So, this process is a continuous one and it continues to occur even after the bag of waters has broken (yes, even with a big gush); there is always some fluid present – so there is no such thing as “dry labor” – another big reason being given as a reason for C-Section these days!
Back again to “low amniotic fluid” at the end of pregnancy. Women are being told to get ultrasounds done to assess not only growth of baby, but also fluid levels. Then they are told that it is falling. One, isn’t it normal for amniotic fluid levels to drop to allow for the baby to descend? If not, the baby would be floating high up, as we see sometimes when fluid levels remain high. In any case, the mother’s body and the baby in their wisdom almost always know what they are doing .. as long as both are healthy, we need not assume otherwise.
Two, what about using traditional hands-on skills to assess if all is indeed well? As midwives, when we feel around the baby, we are usually able to tell if the baby has adequate space around her, if the mother’s belly feels tight around the baby, or if there is so much fluid that we can feel a “thrill” of fluid moving around. As Gloria Lemay points out, what the Sonologist is able to measure is like “measuring water around an adult from the bottom of a see-through plexiglass water tub. In such a scenario, it would be difficult to assess how much water is in the tub above the body that is resting on the bottom of the tub. You might be able to get an idea of the water volume by measuring how much water was showing below the elbows and around the knees, but if the elbows were down at the bottom of the tub, too, you might think there was very little water. This is what the technician is trying to do in late pregnancy—find pockets of amniotic fluid in little spaces around the relatively large body of an 8 lb. baby who is stuffed tightly into an organ that is about the size of a watermelon (the uterus). If most of the amniotic fluid is near the side of the uterus closest to the woman’s spine, it can not be seen or measured.” You can read the full article written by Gloria Lemay here.
Even though official guideline with respect to measurement of amniotic fluid levels, and even Biophysical Profile (AFI – Amniotic Fluid Index – gets 2 points on this scoring system) do not warrant immediate induction, or even worse, a C-Section, parents are usually not given the whole picture as they are “feared” into having one or the other done. Some mothers are asked to get admitted to get an infusion of IV fluids … why not have the mother increase her oral hydration instead? In practice, in the course of a normal labor, sometimes we see very little fluid when the bag breaks, and sometimes we see big gushes. Sometimes we see very little fluid when the bag breaks (forewaters) and then a big gush of fluid after the baby is born (hindwaters). AND – all in almost all these scenarios, the natural process of labor and birth continues without a hitch to enable a healthy birth!
So, get yourself informed .. the risks of induction often outweigh the benefits of induction; and certainly an elective C-section should never be performed for “low amniotic fluid level”. If you and your baby are otherwise healthy, the best practice would be to wait for labor to start on its own.