Fetal ascites caused by ovarian incarceration within an inguinal hernia and development of maternal mirror syndrome

Fetal ascites is a non-specific finding which can be associated with fetal hydrops or an isolated intra-abdominal cause. We describe a case of fetal ascites associated with an intra-abdominal mass suspected to be ovarian in nature and diagnosed in the third trimester. The mother developed maternal mirror syndrome, previously reported to be associated with fetal hydrops but not reported in cases of isolated fetal ascites. Neonatal laparoscopy revealed the left ovary was oedematous and enlarged next to an inflamed and oedematous deep ring suggesting a previously incarcerated ovarian inguinal hernia, causing reactive ascites due to vascular compromise. Both the baby and mother went on to make a full recovery. This case both highlights a rare cause of fetal ascites associated with an ovary antenatally incarcerated in an inguinal hernia and maternal mirror syndrome associated with isolated ascites due to this pathology.