In rare cases of ectopic pregnancy, there may be fertilized eggs, one outside the uterus and the other inside. This is referred to as a heterotopic pregnancy. Often the intrauterine pregnancy is located later than the ectopic, in particular due to the painful emergency nature of ectopic pregnancies. Since ectopic pregnancies are typically observed and eliminated very early within the pregnancy, an ultrasound might not locate the additional being pregnant within the uterus. When hCG degrees continue to upward push after the removal of the ectopic pregnancy, there is the risk that a pregnancy inside the uterus remains feasible. This is normally located via an ultrasound.
Although rare, heterotopic pregnancies are getting greater common, probable because of improved use of IVF. The survival rate of the uterine fetus of a heterotopic pregnancy is round 70%.