Final answer:
The three main causes of decreased fetal variability are alcohol consumption during pregnancy, infection by the rubella virus, and inadequate amniotic fluid levels.
Step-by-step explanation:
Three main causes of decreased fetal variability are alcohol consumption during pregnancy, infection by the rubella virus, and inadequate amniotic fluid levels.
- Alcohol consumption: Exposure to alcohol during pregnancy can result in fetal alcohol spectrum disorder, which can cause cognitive deficits, developmental delays, and behavioral issues.
- Infection by rubella virus: If a pregnant woman contracts rubella, the virus can be transmitted to the fetus and lead to birth defects such as heart defects and vision and hearing problems.
- Inadequate amniotic fluid levels: Too little amniotic fluid (oligohydramnios) or too much (polyhydramnios) can indicate potential problems for the mother and baby, resulting in developmental issues and life-threatening conditions like hypoplastic lungs.