Two Types of Pregnancy at the Same Time
What is a Heterotopic Pregnancy?
Although the incidence of heterotopic pregnancy is presently low, it is an increasing phenomenon. It is defined as the simultaneous development of a gestation within the uterine cavity and a gestation outside the uterine cavity. That means there is a combination of pregnancies in one woman's body. She has an ectopic pregnancy as well as a uterine pregnancy simultaneously. Women undergoing ovulation induction or other types of assisted reproduction techniques such as In Vitro Fertilization (IVF) and Gamete Intra-Fallopian Transfer (GIFT) are most susceptible to this type of pregnancy.
Top 4 Risk Factors for Women Undergoing ART
The occasion of heterotopic pregnancy risk is the same as an ectopic pregnancy for normal pregnancies, however, there are much higher risks for women in ART. These risk factors include:
· Higher incidence of multiple ovulation
· Higher incidence of tubal malformation
· Higher incidence of tubal damage
· Technical factors in embryo transfer
Top 9 Risk Factors for the General Population
The risks for the general population have been exacerbated over the past twenty years, seeing a four-fold increase in the number of heterotopic pregnancies among women who are not on ART. The risk factors for this group are:
· The increase in incidence of PID (pelvic inflammatory disease)
· Prevalent use of IUDs
· Increase in microsurgery, especially tubal surgery
· Previous ectopic pregnancy
· Scarring of fallopian tubes
· Progestin-only birth control pills
Each of these risk factors increases the odds for an ectopic pregnancy 2 to 7 times, with pelvic inflammatory disease being the most prevalent. PID is the result of sexually transmitted diseases (STDs) in most cases. The ratio has gone from 1 in 30,000 pregnancies in the general population, to 1 in 10,000 pregnancies for couples not using assisted reproduction techniques. However, 1 in 100 couples who conceive with ART experience heterotopic pregnancies.
Difficult to Diagnose
Quantitative assays (testing for levels) for the beta subunit of hCG along with the use of transvaginal ultrasound has made a solid contribution to the early diagnosis and treatment of this condition. When the beta-hCG levels reach a place where they line up with 6.5 weeks gestation, it is expected that an intrauterine pregnancy can be detected. If one is not seen, then the suspicion of an ectopic pregnancy is raised. The problem arises when there is an intrauterine pregnancy as well as an ectopic pregnancy discovered. In other types of ectopic pregnancies, the beta-hCG levels are usually lower than those of a normal intrauterine pregnancy of the same duration. Since there is a normal pregnancy alongside the ectopic pregnancy, the beta-hCG levels are more normal. The readings are useful in ruling out an ectopic pregnancy but not especially useful in diagnosing the presence of a heterotopic pregnancy.
Another thing that makes this type of pregnancy hard to diagnose is the presence of a gestational sac in the uterus, which then lowers the suspicious of an ectopic pregnancy at the same time. Ultrasound investigation is necessary to evaluate the situation properly. As it is, nearly 85% go undetected until the ectopic pregnancy ruptures. Usually, once the intrauterine pregnancy is discovered by ultrasound, the second pregnancy is identified within a couple of weeks.
Treating Heterotopic Pregnancies
The obvious problem comes up when treatment is administered. The viability of the uterine pregnancy has to be carefully considered and much weight rests on the physical condition of the woman as well as the skill of the surgeon. Ideally, a laparoscopy is performed to remove the ectopic pregnancy before it ruptures, without interfering with the uterine pregnancy. Should the ectopic pregnancy rupture the risk of miscarriage of the viable pregnancy increases greatly. Sometimes an injection is administered to terminate the ectopic pregnancy, but the danger to the intrauterine pregnancy is significant.
Early diagnosis is the key to effective treatment and term pregnancy. First trimester miscarriage is the biggest concern and, since the number of heterotopic pregnancies has increased so much, the need for effective treatment is pressing.