Can multiple births be reduced by changing assisted reproductive technology practices?

This study examined the multiple births that can occur as a result of assisted reproduction technology. 

Assisted reproductive technology (ART) is used in infertility. In ART, the eggs and sperm are handled for the purpose of establishing a pregnancy. It includes procedures such as in vitro fertilization (IVF) where the sperm fertilizes the egg in a laboratory dish outside the body, and doctors implant it into the woman's uterus.

Since the introduction of ART in the United States there has been an increase in multiple births, especially the number of twins born. A multiple birth is when two or more babies are born and at least one is born alive. Multiple births carry increased risks of illness and death to the mother and baby. 

This study examined the impact of ART on multiple births.

134,381 cases of embryonal transfer (ET), which is the implantation of an embryo (a fertilized egg) into the womb, were included in this study.

The ART cycles were classified as fresh (using newly fertilized embryos) or frozen/thawed (using previously fertilized and frozen embryos that were thawed), and as autologous (woman's own eggs) or donor (donor eggs).

51,262 of these cycles resulted in live births. Among these live births, 73.5% were a single baby and 26.5% were multiple births. Of the multiple births, 96.8% were twins and 3.2% were triplets or more.

Among multiple births, 59.1% resulted from fresh autologous cycles, 21.7% resulted from frozen/thawed autologous cycles, 14.1% from fresh donor cycles and 5.1% from frozen/thawed donor cycles.

Most multiple births among patients using fresh embryos from autologous eggs involved the transfer of two embryos (81.2%) and patients less than 35 years of age (65.1%).

Most multiple births among patients using donor eggs resulted from the transfer of two fresh fertilized embryos (59.7%), followed by the transfer of two frozen/thawed embryos (22.3%).

This study concluded that the number of multiple births can be reduced by implanting just one fertilized egg into the womb of women under the age of 35. 

This was a retrospective study, so the researchers looked back at data collected by other medical professionals. They may not have been able to take individual factors that affected patients into account. 

Talk to your physician if you would like more information on assisted reproduction.