Management of heterotopic pregnancy
A heterotopic pregnancy is the presence of an EP in parallel with a viable intrauterine pregnancy. The natural incidence is around 1 in 30,000 pregnancies. There is a higher rate seen in association with the use of assisted reproductive technology, in particular IVF-ET and more so when more than one embryo is transferred in a single cycle (8).
The aim of management is to avoid harm to the mother and preserve the viability of the intrauterine pregnancy where possible.A heterotopic pregnancy can present as haemodynamic instability and symptoms of intraperitoneal bleeding in a pregnant woman. She may have previously been assumed clinically or with ultrasonography to have only an intrauterine pregnancy. In such a situation, the safest approach will be to treat as if she has a bleeding EP by beginning resuscitation and arranging urgent surgical management. A more common mode of presentation is at the follow-up scan following IVF-ET where intra- and extrauterine gestation sacs can sometimes be seen. The value of the serum hCG concentration lies only in determining if it is above or below the discriminatory zone, as more subtle trends such as a suboptimal rise in hCG from the EP will be masked by the intrauterine pregnancy’s production of hCG.
Medical management is contraindicated in the presence of a viable intrauterine pregnancy, and the experience of expectant management is limited to a small number of case reports, meaning the mainstay of treatment is surgical (38). Avoiding maternal blood loss and thereby maintaining an adequate blood supply to the uterus will give the best chance of ongoing viability to the intrauterine pregnancy.
Surgical management can be undertaken with precautions taken to safeguard the intrauterine pregnancy. Laparoscopy is performed without the use of a uterine manipulator and lower intra-abdominal pressures of gas are used. This avoids undue gas pressure on the fundus of the uterus, the muscle of which is further relaxed with general anaesthesia. There is minimal use of electrical energy (diathermy) or its use is avoided altogether by using laparoscopic suturing or ‘ultrasonic’ instruments. Postoperative analgesia is limited to those safe in pregnancy and non-steroidal anti-inflammatory drugs are avoided. Anti-D immunoglobulin should be given as with rhesus-negative women with EP. A follow-up ultrasound scan to assess viability is essential as despite best practice around 30-40% of intrauterine pregnancies associated with heterotopic pregnancies are found to be non-viable after treatment for the EP (39).