Multifetal Pregnancy Reduction - Topic Overview
Multifetal pregnancy reduction (MFPR) is a procedure used
to reduce the number of fetuses in a multiple pregnancy, usually to two. When a
pregnancy involves three or more fetuses (high-order pregnancy), the risks of
miscarriage, stillbirth, and lifelong disability increase with each additional
Assisted reproductive technology (ART) and
fertility drugs have greatly increased the number of
multiple pregnancies in America.
The goal of MFPR is to increase
the chance of a successful, healthy pregnancy. Multifetal pregnancy
- Is usually done early in a pregnancy, between the 9th and 12th
- Is most often performed when there are four or more fetuses
- Can be used to reduce triplets to twins.
- Is known as "selective
termination" when it involves a fetus with severe defects or one that is
expected to die later in the pregnancy, which would threaten the life of the
surviving fetus or fetuses.
A multifetal pregnancy reduction improves your chances of
avoiding miscarriage, carrying your pregnancy longer, and delivering one or
more healthy babies:1
How does a triplet-reduced-to-twin pregnancy compare with a triplet pregnancy?
Births and losses of twins after MFPR
Births and losses of triplets (no MFPR)
|Percent of planned babies born, taken home|
|Premature birth before 32 weeks|
|Premature birth before 28 weeks|
|Miscarriage before 24 weeks|
|One or more fetal deaths during the pregnancy|
27 out of 1,000
92 out of 1,000
The most common method of fetal reduction
is transabdominal MFPR. For this procedure, the doctor uses
ultrasound as a guide and inserts a needle through the
woman's abdomen and into the uterus to the selected fetus. The doctor injects
the fetus with a potassium chloride solution, which stops the fetal heart from
Because it is very small during the first trimester, the
dead fetus is usually absorbed by the mother's body. This may include some
vaginal bleeding. This absorption process is the same process that happens in
vanishing twin syndrome.
The risks of multifetal pregnancy reduction
- Miscarriage of the remaining fetuses. Of
pregnancies with three, four, or five fetuses, about 5% of pregnancies miscarry
after being reduced to twins.2 But overall the
risk of a fetal death is higher for a triplet-or-more pregnancy than after
having MFPR.1, 3 See the
- Premature birth. But this risk is lower than it
is for a triplet-or-more pregnancy.1, 3 See the table above.
- Infection of the abdomen or uterus (rare).
What to think about
The American Society for
Reproductive Medicine and the American College of Obstetricians and
Gynecologists strongly recommend careful use of infertility treatment in the
effort to avoid the risks of a triplet-or-more pregnancy and of MFPR. When
embryos are transferred to the uterus, this means limiting the number of
embryos that are transferred for each treatment cycle.