by Jordan S. Saalfrank, MSW, CD(DONA)
This question comes up a lot in Fort Wayne's birth community: "Can the placenta adequately support my baby after 40 weeks gestation?" There are many reason's why this seemingly simple question is actually quite complex and difficult to answer. But the short answer is: yes. 40 week placentas are more than capable to sustain a healthy baby in the womb. Let's take a quick look at why our medical society has us so overly concerned about 40 week placentas before we talk about the long answer.
The industrialized, ultra-conservative birth culture in the US has led the community to believe that any pregnancy beyond 40 weeks is considered "late" and requires intervention. Most care providers in Fort Wayne tell their patients up front that they will not be allowed to stay pregnant after 41 weeks. When in actuality "postdate" or "postterm" is defined as "a pregnancy that goes beyond 42 weeks gestation" (Lowdermilk, Perry, 2000). What has happened in our culture to produce such doubt from our doctors in our bodily design? As Valerie El Halta so wisely pointed out in "Normal Birth: Do We Believe? Can We Remember?": "The obstetrician may say to the pregnant woman, through attitude, words or continual reliance on technology, "You have to prove to me that you can give birth to a baby"' (Midwifery Today, 1998). This kind of doubt only gets into the cracks of a new mom's natural uncertainties and propels her into more self-doubt.
How have we gotten to this point of inducing labor before a baby is even truly defined as "overdue"? The short answer: lawsuits. A doctor sued for malpractice is labeled "less liable" for a maternal or fetal death if they show "proactive" approaches to managing a pregnancy and labor. This means managing pregnancy and labors and inducing. So inevitably due dates have become a ticking clock for doctors rather than what they truly are: GUESS DATES.
Would you agree with me that every woman is different? From lifestyle to family to physiologic make-up; women are different. A little wheel that predicts a due date isn't going to be right very often. And since every woman's cycle varies it is nearly impossible to predict when the gestation began and how that woman's body will grow that baby (unless the woman tracked her basal temperature and knows the date of conception). The truth is, over 90% of the time a woman's body will grow the baby it can birth! Belief in the birth process that has been happening over thousands of years needs to be reclaimed and nourishing expectant families. Valerie El Halta goes on in her article to say: "The midwife, on the other hand, with her attitude that birth is, in most instances, a reliable event, says to this same woman, "You have to prove to me that you cannot have a baby!"" We need every woman to be supported in this way and to stop the spreading of doubt in our design to normally birth babies without intervention.
So back to the long answer: Can a 40 week old placenta properly sustain a baby in the womb?" Women's bodies have been designed to sustain a baby well for 42 weeks. While the risk of newborn death or stillbirth is very low, after 42 weeks gestation the risk does increase (BJOG. 2009;116(5):626-636). But this is where a patient care provider, one who BELIEVES in the process and a woman's body to birth, and technology can help calm some of those fears. A patient care provider tracking fetal movements and doppler technology to listen to cord and placental blood flow, babies can be monitored for any signs of a need to intervene. Also biophysical profiles or non-stress tests can be used to evaluate baby and whether there may or may not be any danger in continuing to stay pregnant after 42 weeks. This is a non-invasive office procedure that listens to baby's heart rate, measures the movements of baby and sometimes looks at amniotic fluid volume.
A short pause for caution here: amniotic fluid levels are constantly changing as baby sucks, swallows and pees. Sometimes low fluid levels can just be a time where baby hadn't peed yet or mama hasn't kept her water intake levels up. It could also be a sign that labor is coming. It is very common to show low fluid and lose a bit of weight before onset of labor. In any case, low fluid levels alone are not an immediate need to intervene (Cochrane Database Syst Rev. 2008). It can be ok to ask to come back to the office the following morning for another analysis and then work in that time to drink appropriate amounts of water and rest. If the second profile shows signs of low fluid again than that can be a good time to discuss intervention and what that would look like for you.
40 week placentas are still very viable and able to nourish baby. Very little is understood about how and when the body and baby decide to move into birth. What is known "is that the most important trigger is a surge of hormones released by the fetus. This hormone surge, which prepares the lungs and digestive system for life outside the womb, signals the fetus's readiness for birth. In response to these signals, hormone receptors in the woman's uterus turn on and the muscles in her uterus change to allow her cervix, at the lower end of her uterus, to open. In short, when a woman goes into labor on her own, this is a powerful signal that her baby is ready to be born and that her body is ready for labor" (Childbirth Connection.org). I would love to see care providers here in Fort Wayne change their mode of operation to believing women need to PROVE THEY CAN'T HAVE A BABY instead of fear-based care and perhaps this question wouldn't be so commonly asked.
