First-trimester diagnosis of conjoined twins aided by spatiotemporal image correlation.

A case of conjoined twins after frozen embryo transfer at early blastocyst stage is described. The diagnosis was made early at 7 weeks by vaginal sonography and later confirmed by spatiotemporal image correlation with power Doppler. The value of spatiotemporal image correlation with Doppler in facilitating an early diagnosis of conjoined twinning is discussed.