Which fetal anomalies are associated with polyhydramnios?

Polyhydramnios, or excess amniotic fluid, is often associated with certain fetal anomalies, particularly those affecting the central nervous system (CNS) and gastrointestinal (GI) tract. When there are CNS anomalies, such as anencephaly or spina bifida, the fetus may have difficulty swallowing amniotic fluid, leading to a buildup of fluid in the amniotic sac. Similarly, gastrointestinal tract anomalies, such as esophageal atresia or duodenal atresia, can hinder the normal absorption of amniotic fluid. These conditions cause an imbalance in the regulation of amniotic fluid volume, resulting in polyhydramnios.

In contrast, musculoskeletal disorders, genetic syndromes, and cardiac defects can lead to complications during pregnancy but are less directly linked to an increase in amniotic fluid volume compared to CNS and GI anomalies. While these conditions can have various effects on fetal development, they do not consistently cause polyhydramnios in the same manner as the specific anomalies associated with the central nervous system and gastrointestinal tract. Understanding these associations can assist healthcare providers in monitoring pregnancies and preparing for potential complications.