1/4. Transition from normal early pregnancy to blighted ovum.Four cases of blighted ovum which had normal pregnancies by earlier ultrasound including embryonic heart activity are presented. There was no unique karyotype associated with this phenomenon. ( info) |
2/4. Sirenomelia associated with a "vanishing twin".A case is presented of twin gestation in which one gestational sac was completely resorbed and the remaining twin was subsequently found to be sirenomelic. First-trimester prenatal ultrasound examination demonstrated a second gestational sac that disappeared 2 weeks later. The sonographic features that led to the diagnosis of sirenomelia in the remaining fetus included severe renal dysgenesis, persistently apposed lower extremities, and absence of fibulae. Postmortem examination, including angiographic studies of the fetus, revealed caudal dysgenesis and a single umbilical artery that arose from the abdominal aorta. Sirenomelia occurs more frequently in twin gestations than in singletons. This case suggests that the association between twinning and sirenomelia may be greater than is currently recognized. Two hypotheses are given to explain this association. ( info) |
3/4. Heteropagus conjoined twins due to fusion of two embryos: report and review.We report on a case of conjoined twinning (CT) consistent with fusion of two embryos followed by resorption of the cranial half of one of them, resulting in a normal male baby with the lower half of a male parasitic twin fused to his chest. Fluorescent in situ hybridization (FISH) studies suggested that the parasitic twin was male, and dna typing studies demonstrated dizygosity. Although incomplete fission is the usual explanation for conjoined twins, the unusual perpendicular orientation of the parasite to the autosite supports a mechanism observed in mares in which early fusion of two embryos is followed by resorption due to compromised embryonic polarity. ( info) |
4/4. An unexpected triplet heterotopic pregnancy after replacement of two embryos.We report a case of a triplet heterotopic pregnancy consisting of an intrauterine monozygous twin pregnancy and a tubal pregnancy after replacement of only two embryos in an in-vitro fertilization cycle with donor spermatozoa. This case demonstrates that sonographic demonstration of two intrauterine pregnancies after transfer of two embryos does not exclude the presence of an ectopic pregnancy. As both heterotopic pregnancy and spontaneous monozygotic twinning are more frequent after the use of assisted reproductive techniques, this combination, although extremely rare, must be kept in mind, especially in older patients with pre-existing tubal damage. ( info) |