The fetus
usually dies within a few weeks of conception, and a recent
review did not identify any case in which a fetus of
paternal (diandric) origin survived to term (1). Very rarely,
a partial molar pregnancy develops with two maternal
and one paternal haploid set (digynic). In these cases,
the placenta is small, the villi show minimal hydropic
changes, and the fetus is growth-restricted. Some of
these pregnancies have been reported to result in live
births, with subsequent early neonatal death (2).
Of 3,000 women with partial hydatidiform moles, 0.1%
had a choriocarcinoma. Persistent trophoblastic disease
or malignant complications are much more common
with a complete molar pregnancy than with a partial
hydatidiform mole. The incidence of these complications
is approximately 8% and 0.5% respectively, compared
with a risk of 1:50,000 after a full-term pregnancy.