Читать книгу Protocols for High-Risk Pregnancies - Группа авторов - Страница 14

Alcohol use during pregnancy has been associated with an increased risk of fetal death in some, but not all, studies. For example, an increased risk of miscarriage was reported in women who consumed more than three drinks per week (adjusted odds ratio 2.3; 95% confidence interval [CI] 1.1–4.5), compared to women who reported no alcohol consumption. In a Danish study of nearly 90 000 pregnant women, a higher risk of fetal death after 22 weeks’ gestation (adjusted hazard ratio 2.20; 95% CI 1.73–2.80) was observed in pregnant women who reported either three or more drinks per week or two or more binge‐drinking episodes, compared to women who did not drink.

Alcohol exposure during pregnancy also increases the risk of low birthweight and extreme preterm birth (<32 weeks’ gestation), factors which may contribute to higher rates of neonatal morbidity and mortality and may have long‐term neurodevelopmental consequences.

Most studies have focused on the negative effects of alcohol on fetal development. Alcohol is a known teratogen and exposure early in pregnancy, during the period of organogenesis, has been associated with growth restriction and a constellation of physical abnormalities, including dysmorphic facial features, microcephaly, cardiac defects, and eye and ear abnormalities. Exposure to alcohol at any point during the pregnancy can compromise development of the fetal brain. Prenatal alcohol exposure is one of the leading causes of mental retardation and may result in long‐term deficits in cognitive, behavioral, and emotional functioning.

Fetal alcohol spectrum disorders (FASD) encompass several diagnostic subtypes. Children with fetal alcohol syndrome (FAS) are the most severely affected and present with characteristic facial features (e.g., thin upper lip, small, wide‐set eyes, upturned nose), microcephaly, small stature, and cognitive deficits, including developmental delays and lower IQ, as well as emotional and behavioral problems. Children with alcohol‐related neurodevelopmental disorder (ARND) lack the characteristic facial defects and growth retardation seen in children with FAS but have alcohol‐induced mental impairment.

The effects of alcohol exposure on the developing fetus are variable. While any amount of alcohol consumption may have adverse effects, binge drinking is especially concerning as it has been associated with higher risk of FASD. Children born to women of lower socioeconomic status appear to be more susceptible to the effects of alcohol in utero, a finding which suggests that other factors, including nutritional status and environmental exposures, may contribute to the pathophysiology of FASD. Currently, there is no known amount of alcohol consumption during pregnancy which is considered to be safe.

Prevalence estimates of FAS have varied widely from 0.5 to 3 per 1000 live births; however, studies using in‐person assessments of school‐aged children report higher estimates of FAS: 6–9 per 1000 children. Few estimates for the full range of FASDs are available; the most current estimate of the prevalence of FASD among US children is approximately 1%.