The goal of the current review is to present the figures essential for counseling, when hydatidiform mole and normal fetus occur together. Previous reviews of prognosis and risks when mole and fetus are observed together did not adjust for differences in genetic constitution and thus varying risks for gynecologic and obstetric complications. A literature search from 1903 to 1989 revealed 113 reports of pregnancies with mole and fetus in which there appeared to be no major malformations or cytogenetic abnormalities; 87 of those were intended to continue. This group provides the most appropriate risk figures, when mole and karyotypically normal child are detected by first or second trimester prenatal diagnosis. Fifty-two pregnancies (59.8 per cent) proceeded to the 28th week without spontaneous abortion or interruption of pregnancy. None of the children delivered before week 28 survived. Of the pregnancies continuing beyond this time 69.2 per cent of the children survived, 7.7 per cent were live-born with unknown long-term outcome, 17.3 per cent died neonatally, and 5.8 per cent succumbed before delivery. Persistent trophoblastic disease was reported in 19.2 per cent of pregnancies interrupted at diagnosis, as well as in 9.1 per cent of those intended to continue. Due to advances in prenatal diagnosis, clinicians will be confronted with counseling in pregnancies with mole and fetus more often than expected from the literature. Chorionic villus biopsy or amniocentesis can disclose those triploid gestations without possibility of a surviving child. First trimester ultrasound demonstration of a partially cystic placenta and abnormal high se-hCG values should initiate prenatal diagnosis for evaluation of the fetal karyotype, before deciding whether to abort or continue the pregnancy.