HP is the simultaneous presence of intrauterine and extrauterine pregnancies. The existence of HP is unusual in natural conception cycles with a reported incidence of 0.08%. However this incidence increases to up to 1% in assisted reproductive techniques and 5% of pregnancies following in vitro fertilization. HP is thus rarely considered as a differential of first trimester bleeding following natural conception as was in our case, and thus likely to be missed [1, 8]. Furthermore, research shows that the main risk factors associated with ectopic pregnancy are tubal surgery and pelvic inflammatory disease [1, 2], which were nonexistent in our patient. The suspicion of HP in this patient was thus very unlikely.
In HP, the ectopic pregnancy could be cervical, tubal, ovarian, on broad ligament or intraabdominal [9, 10]. Of these, 95–97% are tubal with the most common site being the ampulla (80%), followed by the isthmic segment of the tube (10%), then fimbriae (5%) and the corneal and interstitial segments (2–4%) . As described in literature the ectopic component of this pregnancy was tubal and specifically ampullary which is the most frequently observed site.
The intrauterine component of an HP could be a single or multiple gestations, live or dead, could be aborted spontaneously or progress to term safe delivery . In our extensive search of literature using Google scholar, Pubmed, African journal online (AJOL) and HINARI search engines, no case of a blighted ovum as the intrauterine component of an HP had been reported. This case is thus of particularity as it is does not only present an HP in natural conception but also describes a blighted ovum as the intrauterine component of the HP, which is a true rarity.
Tal and colleagues in a review reported that 70% of HPs are diagnosed between 5 and 8 weeks, 20% between 9th and 10th week and remaining 10% from 11th week . The case reported falls in line with the 20% of people diagnosed between 9th and 10th week. An ectopic pregnancy and a blighted ovum have similar presentations of: no symptoms, lower abdominal pain, and vagina bleeding. This was the case with our patient. The similarity in symptoms and rarity of its co-occurrence could make one to preclude the diagnosis of the other.
Diagnosis usually requires a high index of clinical suspicion as patients might be asymptomatic. Confirmation is usually by trans-vaginal or trans-abdominal ultrasonography . A blighted ovum is diagnosed by a trans-vaginal sonographic mean gestational sac diameter (MGSD) of > 20 mm with no foetal pole or MGSD of > 25 mm with no foetal pole on trans-abdominal sonography . The standard would have been a trans-vaginal sonography, this was however not possible due to poor material and human resources. Our patient benefited from a trans-abdominal ultrasound scan which revealed an MGSD of 29.9 mm with no foetal pole confirming a blighted ovum. Similarly, ectopic pregnancy was diagnosed by left adnexal mass on trans-abdominal ultrasonography with a positive pregnancy test.
A blighted ovum could be managed either expectantly or by evacuation. Both methods have been shown to be efficacious with expectant management within 3 weeks being advisable due to decreased risk of infection and complications . However the patient’s choice often takes precedence. In our case, evacuation was done on request of the patient secondary to persistent bleeding. Management of ectopic pregnancies could be medical or surgical. The Fernandez score is used as a guide to decide on mode of management. Medical therapy in HPs with leaving foetus is however controversial, as Methotrexate has undesirable effects on the developing foetus . This patient’s Fernandez score could not be gotten as our facility was unequipped to measure human chorionic gonadotrophin and progesterone levels. Persistent bleeding and unavailability of methotrexate prompted surgical management which was successful.
The case presented confirms that HP can occur in the absence of predisposing factors, and that the detection of a blighted ovum should not preclude the possibility of a simultaneous ectopic pregnancy. We therefore advocate in all pregnant women with first trimester bleeding even in the presence of a confirmed blighted ovum, a complete review of the whole pelvis including adnexa during ultrasound scan.