A heterotopic pregnancy is a rare complication of pregnancy in which both extra-uterine (ectopic pregnancy) and intrauterine pregnancy occur simultaneously. It may also be referred to as a combined ectopic pregnancy, multiple‑sited pregnancy, or coincident pregnancy. Heterotopic pregnancy was rare. Risk factors of heterotopic pregnancy include ART, pelvic inflammatory disease, prior tubal surgery including salpingectomy and reconstructive tubal surgery Heterotopic pregnancy can have various presentations. It should be considered more likely.
- After assisted reproduction techniques.
- With persistent or rising chorionic gonadotropin levels after dilatation and curettage for an induced or spontaneous abortion.
- When the uterine fundus is larger than for menstrual dates.
- With more than one corpus luteum.
- With absence of vaginal bleeding in the presence of signs and symptoms of ectopic gestation and
|Ruptured heterotopic pregnancy on ultrasound|
Heterotopic pregnancy was easy to be missed or misdiagnosed. Except the reason of patients who did not visit doctors in early pregnancy, the main cause might be that gynecologists rely too much on ultrasound conclusion, while radiologists omit to scan the pelvic area carefully in the sign of intrauterine pregnancy. In a review of 82 cases of heterotopic pregnancy, 33% of cases only simply reported a normal single or multiple intrauterine in a previous ultrasound scan. However, there was also the possibility that ectopic pregnancy did not grow as fast as intrauterine pregnancy which made it difficult to diagnose at early time. In unruptured and ruptured heterotopic pregnancy after ART, 66.7% and 85.7% cases were diagnosed by ultrasonography before 7 weeks of pregnancy respectively . To date, there was no similar data concerning natural heterotopic pregnancy.
In our case, ultrasonography and pelvic MRI did not find the existence of ectopic pregnancy until 79 days of pregnancy. It might be easy to make a diagnosis of GTN and start chemotherapy in this case, as high HCG level persisted after missed abortion. Although no HCG monitoring guideline was recommended in GTN after non-molar pregnancy , from our experience we speculated that HCG should keep on increasing rapidly instead of slightly decreasing in the last week of surveillance. Thus, considering the prior tubal surgery history and the trend of HCG level, we preferred to monitor carefully instead of urgent chemotherapy. Finally, ectopic pregnancy mass was found. The successful diagnosis avoided chemotherapy and rupture of ectopic pregnancy at the same time.
In a heterotopic pregnancy there is one fertilized ovum which implants normally in the uterus, and one fertilized ovum which implants abnormally, outside of the uterus.
In the general population, the major risk factors for heterotopic pregnancy are the same as those for ectopic pregnancy. For women in an assisted reproductive program, there are additional factors: a higher incidence of multiple ovulation, a higher incidence of tubal malformation and/or tubal damage, and technical factors in embryo transfer which may increase the risk for ectopic and heterotopic pregnancy.
A possible pregnancy must be considered in any woman who has abdominal pain or abnormal vaginal bleeding. A heterotopic pregnancy may have similar signs and symptoms as a normal intrauterine pregnancy, a normal intrauterine pregnancy and a ruptured ovarian cyst, a corpus luteum, or appendicitis. Blood tests and ultrasound can be used to differentiate these conditions.
Heterotopic pregnancy is treated with surgical removal of the ectopic gestation by salpingectomy or salpingostomy. Expectant management has been successfully applied in select cases. Successful salpingocentesis has also been reported.
Extrauterine pregnancies are non-viable and can be fatal to the mother if left untreated. The mortality rate for the extrauterine pregnancy is approximately 35%.
The prevalence of heterotopic pregnancy is estimated at 0.6‑2.5:10,000 pregnancies. There is a significant increase in the incidence of heterotopic pregnancy in women undergoing ovulation induction. An even greater incidence of heterotopic pregnancy is reported in pregnancies following assisted reproduction techniques such as In Vitro Fertilization (IVF) and Gamete intrafallopian transfer (GIFT), with an estimated incidence at between 1 and 3 in 100 pregnancies. If there is embryo transfer of more than 4 embryos, the risk has been quoted as 1 in 45. In natural conceptions, the incidence of heterotopic pregnancy has been estimated to be 1 in 30 000 pregnancies.
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- "Heterotopic Pregnancy". Juniper Publishers.
- Kirk, E.; Bottomley, C.; Bourne, T. (2013). "Diagnosing ectopic pregnancy and current concepts in the management of pregnancy of unknown location". Human Reproduction Update. 20 (2): 250–61. doi:10.1093/humupd/dmt047. PMID 24101604.