Introduction
Heterotopic (also called heterotrophic) pregnancy is the simultaneous
occurrence of two pregnancies in two different implantation sites. Most
of the time one of the pregnancies is intrauterine and the other is an
ectopic pregnancy. HP is estimated to occur in 1 every 3900 pregnancies
after assisted reproductive technologies (ART) and reaching up to 1.5 in
every 1000 pregnancies 1. In some studies, their
reported incidence is as high as 1 in every 100 pregnancies after ART
2,3,4. Although the true incidence after ART is difficult to confirm, it
is postulated that such an increased incidence in these patients after
ART, is related to previous tubal pathology, multiple ovulations or
multiple embryo transfers 2.
Following a spontaneous pregnancy, however, the incidence of HP is rare.
In a large review of the world’s literature on combined intrauterine and
extrauterine pregnancies, the reported incidence was 1 every 30,000
pregnancies 4. Spontaneous HP - in particular - poses
a real challenge for healthcare professionals not only in treatment but
in diagnosis. This is due to multiple factors, partly due to their
rarity and unexpected occurrence. Ectopic pregnancies per se pose a
diagnostic challenge on their own accord. HP will pose an even more
diagnostic uncertainty; as seeing an intrauterine gestational sac may
give false reassurance and B-human Chorionic gonadotrophins (β-hCG)
serial measurements may not be useful due to the presence of two
pregnancies in different locations 5.
In our article, we present a case of spontaneous conception resulting in
a HP. We review the diagnostic features, imaging, and management.