Prior to writing this article, the most I knew about placentas was that people ate them sometimes (I now know others bury them as well). But these discs do more than serve as a postnatal snack for mothers. Connected by the umbilical cord, these discs shuttle oxygen, blood, and necessary nutrients to a baby while it grows. Placentas are basically a lifeline for fetuses, which is why you will usually hear mothers decline an alcoholic beverage during their nine months of pregnancy. But what happens when a mother bypasses the recommendation to forgo drugs and alcohol during pregnancy?
A placenta has two sides: one that faces the baby and one that faces the mother, called the syncytiotrophoblast. This side is bathed in the mother’s blood, allowing for plenty of surface area to facilitate the flow of oxygen, nutrients, and waste between the mother and baby. However, this side also possesses norepinephrine and serotonin transporters. Norepinephrine is the hormone that triggers your fight or flight response, and serotonin helps with constriction of the blood vessels. In a pregnancy, serotonin encourages uterine contractions, which happen when a baby is ready to pop out. However, while waiting for the fetus to come to term, the body needs something to help it prevent these contractions, which is where the placenta’s transporters come in. The transporters clear away serotonin and norepinephrine, and subsequently hold off the contractions until the baby comes to term.
All this to say, the placenta functions best when there is no buildup of serotonin or norepinephrine to induce early birth. Unfortunately, drugs like cocaine and ecstasy inhibit these transporters as they would in a nonpregnant person, allowing norepinephrine and serotonin to continue working their magic. Amphetamines, like meth and ecstasy, easily bind to transporters, allowing free access to the placenta. Without any transporters to take these chemicals away, they build up in the intervillous space, stimulating early contractions and decreasing blood flow to the baby.
Maternal substance abuse has many detrimental consequences. The most prevalent one is premature delivery, due to the accumulation of norepinephrine and serotonin. Addiction to meth has been linked to a decrease in caudate nucleus volume, a region of the brain that regulates voluntary movement, memory, reward processing, and emotion. Moreover, Fetal Alcohol Spectrum Disorder, caused by prenatal alcohol exposure, affects limb and facial development, reduces brain and birth weight, and causes cognitive delays and impairments. Finally, prolonged subjection to addictive substances can cause babies to undergo a period of withdrawal after birth, called Neonatal Abstinence Syndrome. Even seemingly harmless drugs like antidepressants can have lasting effects on children. While research may be limited, there is no question that addictive drugs have lifelong consequences on both mothers and their babies.