Intrauterine Drug Exposure—What the Pediatrician Needs to Know. Part 1: General Overview, Transplacental Drug Transfer, Teratogenicity, and Fetal Alcohol Spectrum Disorder

Purpose of Review This review summarizes results of recent surveys that quantitate fetal exposure to various drugs and substances, discusses factors that influence transplacental passage of molecules, highlights evidence that speaks to whether certain drugs are teratogenic or affect fetal growth, and outlines the consequences of fetal exposure to alcohol. Recent Findings Rates of use of alcohol and tobacco and misuse of prescription drugs and illicit substances are lower in women of child-bearing who are pregnant compared to non-pregnant women, but remain distressingly high. Mental health problems and adverse social determinants of health increase the likelihood that a pregnant woman will also have a co-existing substance use disorder. Legalization of marijuana has resulted in lower societal concern about potential long-term effects of fetal exposure. Reports that opioids, cocaine, amphetamines, and hallucinogens act as teratogens have not withstood scrutiny of larger better-controlled studies. Opioids and alcohol have been associated with reduced fetal somatic and cerebral growth. Summary Pregnant women should be advised to abstain from elective use of drugs and substances that can affect the growth of the fetus, neurobehavior of the newborn, and long-term functional potential of the growing child. Of all fetal exposures, alcohol results in the greatest cumulative cognitive deficit across all children and its effects are often silent until children reach school age.