Elective induction of labor at 39 weeks reduces the risk for cesarean section and improves fetal outcomes

Alexander Kofinas M.D. Uncategorized Leave a Comment

Elective induction of labor, the process where a woman is stimulated with some form of medication that helps the uterine cervix soften up and uterine contractions to start; the combination of uterine contractions and progressive cervical shortening constitutes labor. The subject of elective induction of labor as opposed to waiting for the mother to go into spontaneous labor has been one of the significant obstetrical controversies. Many studies have been performed and yet, there are many obstetricians who profess that elective induction is a bad thing and as many who profess that it is a good thing. The better evidence in my judgment tilts in favor of elective induction because it seems that it reduces the risk for cesarean section but more so, prevents significant fetal and neonatal morbidity or even death.

The missing part of these studies: placenta

What is however missing from most of the studies regarding the benefits or risks of elective induction of labor at term is common sense and understanding of placental physiology as well as uteroplacental-fetal vascular interactions. In contrast, there is abundance of bias from both sides of the controversy based on fiction, unsubstantiated believes, and the misconception that everything natural is safe. Maternal mortality during the 19th century in rural England was 25/1000 or 2.5%. So, we have come a long way in protecting our pregnant patients bur much more has to be done. Fetal/neonatal mortality w not as important as maternal mortality at the time and throughout history. It is teleologically sensible that in nature’s interest, a mature reproductive “unit”, aka the mother, is much more important than the uncertainty of a neonate. Therefore, preventing maternal death has been and still is the priority and fetal protection follows. Today, with our relatively advanced obstetrical and surgical capabilities, we have the luxury of not having to face the dilemma, the mother or the baby?

Personal biases dictate what we choose to support

Too much energy and money has been spent trying to learn if elective induction is a better choice than expectant management until commencement of spontaneous labor. Like always in clinical research, most of the studies are flawed and unable to reject the hypothesis they embarked upon to reject; the only benefit of such incomplete studies is that they become the ammunition for physicians to support their biases. Those supporting elective induction use the positive studies and ignore the negative ones, and vice versa. Past century’s philosopher Bertrand Russell describes this succinctly:

“If a man is offered a fact that goes against his instincts, he will scrutinize it closely, and unless the evidence is overwhelming, he will refuse to believe it. If on the other hand, he is offered something that affords a reason for acting in accordance with his instincts, he will accept it even on the slightest evidence. The origin of myths is explained in this way….”

What has been blatantly absent from this dialogue/controversy is the fetus and the placenta. We all know that fetal monitoring with electronic fetal heart recordings (EFM) is a worthless or even harmful method for the evaluation of fetal well-being. Therefore, the way fetal well-being is assured in the majority of pregnancies that make it to term and beyond today is flawed, considering EFM is the “standard-of-care”. Let us not forget that even in normal placentas, the aging process of the placenta is accelerated at term and in some fetuses more than others, creating significant supply/demand mismatch that can put the fetus at serious risk.

Fetal risk for death is high after 39 weeks

Fetuses that remain undelivered beyond 39 weeks face a death risk of 1/300 to 1/500. This might sound a small risk but it accounts for the loss of about 6,000 to 7,000 lives annually in the USA alone. However, for every baby that dies, there are several, babies that come near death but they do not die. These babies will suffer from variable short and long-term morbidities as well as increased infant mortality. So, we allow our patients to go into a wait and see game, just because it has been the natural way for millennia to wait until the baby comes?

Elective induction of labor is not natural but what is?

Death from cardiovascular disease is as natural as scorpions and snakes and yet, we spend billions and billions every year to prevent it. The same is true for most of human maladies. What gives us the right to ignore the life as well as the quality of life of these unfortunate fetuses and their mothers that happened not to be in labor by 39 weeks? There is more than enough evidence out there that delivery at 38-39 weeks is associated with the best neonatal outcomes and reduces the risk for cesarean delivery. If, however, we were to introduce the missing link, the state of fetal-maternal-placental circulation at term, then we could be much more informed in making the proper decision that helps our fetuses to preserve their health and their lives and reduce risks to their mothers. Uterine arteries are the only supplier of oxygen and nutrition to the fetus.

Uterine after blood flow is very important for the fetus

A significant number of even low-risk patients have pathologic uterine artery blood flow and poor placental function. These are the patients who are most likely to end up with a cesarean section under unpredictable emergency conditions, in the middle of the night, as well as, with a dead baby, or a seriously compromised baby whose future will not be what had been written in his/her genes. Fetuses are extremely resilient and have magnificent ways of defending themselves from all kinds of threats. They have the ability to redistribute their most oxygenated blood to their brains and overcome, at least for some time and under non-stressful conditions, placental insufficiency and avoid adverse outcomes.

This however will not be the case, if such fetuses are allowed to remain in utero until onset of spontaneous labor sometime in the future. It should be clear then that the controversy of elective induction or not, despite the fact that on most accounts, elective induction at 39 weeks provides benefits to both, mother and baby, becomes mute in the absence of clear understanding of the state of the fetal-placental-maternal blood flow relationships and the presence or absence of fetal blood flow centralization (brain sparing).

Time to incorporate fetal and placental health in the elective induction process

It is time therefore, that we incorporate fetal and maternal Doppler assessment prior to the decision of elective induction in order to refine our ability to select the mother-fetus couples that would benefit the most, against whatever risks they are going to be exposed. As long as we can provide more benefit for the risk we take, this is good medicine and not the personal believes of any obstetrician. As for the “natural birth” argument being the safe one, it is time for us to realized that harm and death are part of nature and there is nothing to suggest that all natural processes are the safest indeed.