Reducing the number of fetuses for women with a multiple pregnancy

What is the issue?

Women expecting twins, triplets or more, face a higher risk of complications. There are increased risks to the woman, and to their babies, during pregnancy, birth and afterwards. For example, the babies are more likely to die before or after birth, to be born preterm, or to have serious and sometimes long-lasting difficulties. It is possible to reduce the number of fetuses during pregnancy by terminating one or more of them. This is called pregnancy reduction or fetal reduction. This intervention aims to improve the health of the remaining fetus or fetuses. Parents and healthcare providers need evidence that shows clearly whether reducing the number of fetuses leads to better outcomes, and what the risks may be.

Why is this important?

Pregnancy reduction is a very difficult decision for parents. Parents need a full picture of the possible outcomes. Without studies to show if termination is likely to benefit the remaining fetus or fetuses, and what the risks may be, it is harder to make a fully-informed choice.

What evidence did we find?

We found no studies for this Cochrane review (search date 31 July 2015) and so we do not know if the baby or babies who remain after fetal reduction have better outcomes or if there are any risks in the procedure. Evidence from other types of studies does exist but there are problems with making sense of the data.

What does this mean?

For the present, we cannot be sure whether pregnancy reduction does lead to better outcomes for the remaining fetuses, and by how much. We cannot be sure which particular outcomes improve, and what risks may arise. In the future, we may get a better picture, with a different type of study which takes into account parental preference, and which tracks the results. In the meantime, parents can come to a decision about whether they want the option of pregnancy reduction after discussion with their midwives and doctors. The discussion will take into account how acceptable the parents find the intervention, and what outcomes they are hoping to achieve.

Authors' conclusions: 

We found no available data from randomised trials to inform the risks and benefits of pregnancy reduction procedures for women with a multiple pregnancy. While randomised controlled trials will provide the most reliable evidence about the risks and benefits of fetal reduction procedures, reduction in the number of fetuses by selective termination may not be acceptable to women, particularly couples with a past history of infertility. The acceptability of this option, and willingness to undergo randomisation will depend on the couple's social background and beliefs, and consequently, recruitment to such a trial may prove exceptionally difficult.

Read the full abstract...

When couples are faced with the dilemma of a higher-order multiple pregnancy there are three options. Termination of the entire pregnancy has generally not been acceptable to women, especially for those with a past history of infertility. Attempting to continue with all the fetuses is associated with inherent problems of preterm birth, survival and long-term morbidity. The other alternative relates to reduction in the number of fetuses by selective termination. The acceptability of these options for the couple will depend on their social background and underlying beliefs. This review focused on reduction in the number of fetuses.


To assess a policy of multifetal reduction with a policy of expectant management of women with a multiple pregnancy.

Search strategy: 

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 July 2015).

Selection criteria: 

Randomised controlled trials with reported data that compared outcomes in mothers and babies who were managed expectantly with outcomes in women who underwent selective fetal reduction of a multiple pregnancy.

Data collection and analysis: 

We planned that two review authors would independently assess trials for inclusion and risk of bias, extract data and check them for accuracy. However, no randomised trials were identified.

Main results: 

There were no randomised controlled trials identified.