| Ectopic pregnancy. The spatial orientation of three-dimensional ultrasound and its ability to demonstrate the coronal plane of the uterus in its natural position may help in the diagnosis and exclusion of ectopic pregnancy. This is particularly true in cases of heterotropic pregnancy where an intrauterine pregnancy is associated with an ectopic twin gestation. Spontaneous heterotropic pregnancy is rare but may complicate 0.5% of pregnancies arising from IVF treatment with the ectopic gestation located in the cornua (Fig. 13a) or cervix (Fig. 13b). |
