A long held myth that the third trimester of pregnancy was a “safe” time for the expectant mother to use alcohol or illicit substances is being shattered. Many potentially devastating effects of alcohol are fairly well-understood. Researchers have examined the effects of ethanol and saline exposure in pregnant rats during various times of nerve development (synaptogenesis) of the frontal lobes in the rat, including pre- and post-natal periods.
Compared with saline-exposed baby rats, the ethanol-exposed baby rats had significantly more decreases in neuron counts in various parts of the brain, depending on the developmental phase of when the exposure occurred. The exposure levels of alcohol were similar to that of socially acceptable drinking.
Synaptogenesis in humans occurs during the last trimester of pregnancy and continues following birth for several years. Alcohol exposure during these sensitive developmental periods produces brain degeneration and is likely a causal mechanism for fetal alcohol effects in humans.
More recently, researchers used PET scans in third-trimester pregnant bonnet macaques to noninvasively examine glucose metabolic rates (as a marker of brain function) in maternal and fetal central nervous systems after administration of intravenous cocaine in amounts similar to human use.
The macaques that received cocaine had glucose metabolic rates 100% higher than the controls not receiving cocaine. In both macaque groups the fetal glucose metabolic rate was 50% of maternal rates, but the fetal rate in the cocaine group was 100% higher than in the non-cocaine group.
These new findings strongly support the adverse effects of prenatal cocaine exposure to the new born child by disrupting placental blood flow and through direct pharmacological actions upon the developing fetal brain.
These findings demonstrate that pregnant rats and bonnet macaques should not drink any alcohol! But what about humans? The macaque study is especially enlightening since these fetal primate brains have close similarities to the neurophysiology of humans. The wider the variety of species subjected to similar research, the higher the likelihood the findings will apply to humans.
Centuries ago Solomon recognized the momentary pleasure that alcoholic beverages provide, but also warned that in the end there are tragic consequences, “Don’t gaze at the wine, seeing how red it is, how it sparkles in the cup, how smoothly it goes down. For in the end it bites like a poisonous snake; it stings like a viper” (Proverbs 23:31, 32). Are we really ready to face the countless tragedies that occur as a result of pregnant women using alcohol or other illicit substances?
Strong public health efforts to reduce alcohol use in pregnant women are imperative, and even stronger protections for the unborn children of cocaine users would seem warranted.
(This article is part of a continuing series on alcohol. View: <Previous Next>)