First trimester diagnosis of a partial mole with the combined use of ultrasound and chorionic villous sampling.

A patient with vaginal bleeding in the first trimester of pregnancy had a serum human chorionic gonadotropin (hCG) titer of 495,132 mlU/ml and an abdominal ultrasound examination revealed an intrauterine gestational sac without a fetal pole. Two and a half weeks later the hCG titer was 385,000 mlU/ml and a fetal pole was visualized. Transabdominal villous sampling was performed because of the suspicion of a partial mole. Histopathologic examination showed hydropic villi and chromosomal studies were consistent with triploidy. The diagnosis of partial mole in the first trimester of pregnancy was made and the pregnancy terminated.