Hydatidiform mole with a surviving coexisting fetus

A case of hydatidiform mole with a coexistent live fetus--an extremely rare condition--is reported. This is the only known case with delivery of a surviving fetus in which the diagnosis was made antepartum, and the grounds for it are discussed. The rationale for allowing the pregnancy to continue after this diagnosis at the 20th week of pregnancy is also discussed. The values for numerous blood and urinary measurements of fetal and placental status are presented, and the mechanisms of some of these are discussed. Spontaneous labor occurred at the 32d week of pregnancy, and a 1435-g living female infant was delivered. The uterus was evacuated manually and the recovered contents are illustrated, described, and discussed. The infant showed no physical or mental abnormalities at the age of 12 months. Her weight and height were 7170 g and 67.7 cm, respectively, and she had good development.