Infertility Treatment: Risks of Multiple Pregnancy - Topic Overview
Risks during multiple pregnancy
With each additional fetus a pregnant woman carries, health risks
to her and her fetuses increase.
Health risks in a multiple pregnancy. If 100 women* were pregnant with the following conditions, the average number that would experience...
Gestational diabetes is:
|Preterm labor is:
||Preterm birth is:
|Quads||10 or more||60 or more||95 or more||95 or more|
* A risk for 1 person out of 100 is equal to a 1%
Your chances of conceiving a multiple pregnancy
In the general population, less than 3% of births involve twins,
triplets, or more. By contrast, your chances of conceiving a multiple pregnancy
increase when you use fertility drugs and
assisted reproductive technology (ART).
Currently, about 20% of multiple pregnancies occur naturally, while
the other 80% are the result of using fertility drugs or assisted reproductive
technology.2 The majority of these pregnancies are
twins, but there are also more triplets (or more) than in the general
population. The incidence of triplets or more can be controlled during
in vitro fertilization by reducing the number of
embryos transferred, but this is not possible with
superovulation. Risks of multiple pregnancies are 5%
to 8% with clomiphene and superovulation.3 The risks
are even higher with gonadotropins.2
While clomiphene increases the likelihood of pregnancy with one or
two fetuses, gonadotropins increase the risk of conceiving twins or more.
Researchers continue to search for a dependable way to use gonadotropins, yet
effectively prevent triplet-or-more pregnancies.
Balancing ART treatment success versus the risk of conceiving a multiple pregnancy
The risk of conceiving a multiple pregnancy is directly related to
the number of embryos transferred to a woman's uterus. However, the chances of
embryo or fetal loss increase as a woman ages from her mid-30s into her 40s. In
order for a woman over age 35 to maximize her chances of conceiving with her
own eggs and carrying a fetus to term, she typically has more embryos
transferred than does a younger woman. This practice, however, increases her
risk of conceiving multiple fetuses.
Because of the risks of multiple pregnancy to the babies, experts recommend limiting the number of embryos transferred. Based on your age and your situation, your doctor will recommend a certain number of embryos to be transferred.
Women over 40 have a high rate of embryo loss when using their own
eggs. As an alternative, an older woman may choose to use more viable donor