What is IVF?
Of all the available assisted reproductive therapy (ART) treatments, IVF is the most well-known. Although not all women and couples are good candidates for IVF, the procedure has the highest success rates. In vitro fertilization involves a woman taking hormonal medication to bolster ovulation and release multiple eggs during a single cycle. The eggs are then harvested during an egg retrieval. Donor or partner sperm is used to fertilize the egg outside of the body. Once a fertilized egg, or zygote, is formed, the embryo is transferred to a woman’s uterus to implant into the uterine wall.
Concerns over multiple births
Historically, reproductive treatments often carried a few known potential side effects. In most cases, the risks centered around the hormone therapy prescribed to a woman during an IVF cycle. Along with ovarian hyperstimulation syndrome (OHSS), IVF began to gain a reputation for increasing the chance of multiples. Even for women that conceive naturally, carrying multiple embryos simultaneously can pose a risk both to the mother and the babies.
Causes of multiples
While IVF continues to carry a reputation for causing twins and triplets, the truth is a bit simpler. The treatment doesn’t de facto cause multiple births. Instead, the actions of the fertility doctor are what increase the chances. Historically, many fertility centers would transfer multiple embryos to a woman’s uterus in a single cycle to increase the odds of conception. As a result, the potential for carrying multiples rose. Today many centers will opt only to transfer a single embryo during a cycle if the woman is 35 years old or younger. Often, transferring multiple embryos is restricted to older women where conception chances are markedly lower, and even then, many providers max out at 2 total embryos per cycle.
Make an informed decision
In most cases, the infertility diagnosis and a woman’s age will dictate the best fertility treatment. Likewise, the above factors will influence whether a single or multiple eggs are transferred. Women and couples concerned about multiple births should speak with a fertility specialist to understand best practices and what to know before beginning any fertility treatments.