The Inconspicuous and the Obvious: Spontaneous Heterotopic Pregnancies

Valerie Kinsella, Valerie Spillane, Peter McParland, National Maternity Hospital, Dublin


Heterotopic pregnancy is a rare condition, more commonly seen in populations at risk for ectopic pregnancy or those undergoing fertility treatments compared with spontaneous conceptions. Heterotopic pregnancy is the simultaneous coexistence of an intrauterine and an extrauterine gestation (Chadee et al., 2016). Duverney was the first to report heterotopic pregnancy, in 1708, after finding an intrauterine pregnancy during the autopsy of a woman who had died from a ruptured ectopic pregnancy (Avery et al., 2009). By 1970, <500 cases had been reported (Smith et al., 1970). The incidence for heterotopic pregnancy is calculated using the incidence of fraternal twins and of ectopic pregnancy and multiplying both. The incidence of a heterotopic pregnancy is 1:30,000 pregnancies (Kirk et al., 2013), and increases with the use of assisted reproductive treatment. The objective of this abstract is to demonstrate the increasing frequency of these pregnancies at our hospital.


A case series review of heterotopic and abdominal pregnancies over a 12-month period in our hospital.


In our hospital there were 8433 births in 2017 and the number of heterotopic pregnancies were 5 giving an incidence of 0.06% and there was 1 abdominal ectopic pregnancy 0.01%. Of note all of these were spontaneous pregnancies.


Abdominal and heterotopic pregnancies appear to be increasing in frequency, and the incidence of heterotopic pregnancy is thought to be about 1 in 2,600 pregnancies annually; primarily because of assisted reproduction (Crabtree et al., 1994). These up-to-date figures of occurrence would better reflect the experience in our ultrasound department and the idea of it being an exceptional finding is no longer the case. The diagnosis of a heterotopic pregnancy can be difficult and may be delayed until follow-up ultrasound scans are performed. The use of serial βhCG is redundant in these cases (Avery et al., 2009). It is imperative that there is precise ultrasound examination of the adnexae and Pouch of Douglas even in the presence of a normal intrauterine pregnancy (Skrajna et al., 2012). To improve the detection of heterotopic pregnancy, a high-resolution transvaginal transducer should be used, the technique must be meticulous, and the examination performed by an experienced sonographer.

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