Fetal alcohol syndrome
**Core Concept**
Fetal alcohol syndrome (FAS) is a complex disorder resulting from prenatal alcohol exposure, affecting fetal development and leading to various physical, cognitive, and behavioral abnormalities. It is a preventable cause of birth defects and developmental disabilities.
**Why the Correct Answer is Right**
Fetal alcohol syndrome is caused by the teratogenic effects of ethanol on the developing fetus. Ethanol crosses the placenta and interferes with normal fetal development, particularly during critical periods of organogenesis. The exact mechanisms are not fully understood, but it is believed that ethanol disrupts normal cell division, DNA replication, and gene expression, leading to various physical and cognitive abnormalities.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify the primary cause of FAS, which is prenatal alcohol exposure.
**Option B:** This option is incorrect because it does not accurately describe the primary features of FAS, which include growth deficiency, facial abnormalities, and central nervous system impairment.
**Option C:** This option is incorrect because it does not accurately describe the primary cause of FAS, which is prenatal alcohol exposure, not maternal smoking.
**Clinical Pearl / High-Yield Fact**
It is essential to educate pregnant women about the risks of prenatal alcohol exposure and encourage them to abstain from alcohol entirely during pregnancy. The American Academy of Pediatrics recommends that pregnant women avoid all forms of alcohol to minimize the risk of FAS.
**Correct Answer:** D.