Heterotopic pregnancy after a spontaneous conception a case report with a review of clinical, laboratory and imaging findings

Abstract Heterotopic pregnancy (HP) describes the simultaneous presence of two pregnancies at different implantation sites. Usually, one pregnancy is intrauterine and the other one is ectopic. The incidence of HP after assisted reproductive technologies reaches 1:3900, but is very rare after a spontaneous pregnancy, with a reported incidence of 1 to 30,000 pregnancies. Due to its rarity, complex clinical picture, and laboratory findings, it is challenging to diagnose HP. We present a case of spontaneous HP diagnosed in the first trimester by ultrasound (US) and magnetic resonance imaging (MRI) and subsequently managed successfully. We present an analysis of the clinical and laboratory findings as well as imaging, including MRI that we used to diagnose the condition. Additionally, we performed a literature review. Conclusions HP is a very rare condition frequently faced in obstetrics, gynecology, and emergency departments that requires a high index of clinical suspicion. US remains the imaging modality of choice in diagnosing a HP, however, in some cases, an MRI with a reported safety in the first trimester, can be used to provide additional information over US.