Hysteroscopic differences in the gestational sac in asymptomatic blighted ovum and viable pregnancy at early gestation

Objective: To assess differences in the surface anatomy of the gestational sac and endometrium in cases of blighted ovum and viable pregnancies using flexible hysteroscopy. Methods: This was an observational case-control study. Seventeen patients with asymptomatic blighted ovum at gestational ages of 8-13 weeks and 32 women with viable pregnancy at 6-12 weeks of gestation were recruited. Subjects at 8-10 weeks of gestation in both groups were matched for comparison. The gross surface anatomy of the gestational sac and the endometrium was assessed and compared between the two groups. Results: In the viable pregnancy group, the gestational sac was either round (84.4%, 27/32) or ellipsoid and slightly creased (15.6%, 5/32). In the blighted ovum group, the sac appeared collapsed and wrinkled (58.8%, 10/17), small for gestational age (11.8%, 2/17), a combination of the two (17.6%, 3/17), or round and normal (11.8%, 2/17). In general, the sac in subjects with blighted ovum tended to have various degrees of loss in surface tension, collapse in shape, decrease in sac size, and dark blue color at the sac dome compared with the sac in viable pregnancies. Conclusion: The anatomic alterations of the gestational sac reflect impending sac necrosis and abortion in early-stage pregnancy loss. There were no morphologic differences between the two groups in the pattern of capillary distribution on the endometrium or the implantation base.