It depends. “Following IVF, the chance of pregnancy is usually related to the age of the patient,” says Aaron K. Styer, M.D., reproductive endocrinologist and co-medical director of CCRM Boston. “Younger women are more likely to conceive and deliver a live baby than older women: Women who are 35 or younger have the best IVF pregnancy rates, whereas women who are older than 43 have the lowest IVF pregnancy rates.”
Because of that, younger women can transfer fewer embryos. But more factors than age help fertility doctors and patients decide the number of embryos to transfer, including whether the patient has had prior unsuccessful IVF cycles, their medical history, and the stage of embryo development and quality of embryos.
“The goal of an IVF cycle is to transfer the fewest number of embryos possible to achieve the delivery of one full-term baby,” Dr. Styer says, which means the goal is also “minimizing the risks of multiple gestation (i.e. twins and triplets), which can result in complications for mom and baby during pregnancy.”
In general terms, Styer explains, women who are younger than 35 will have one embryo transferred, women ages 35 to 37 will have one or two embryos transferred, women 38 to 40 may have two or three embryos transferred, and women older than 40 may have two to four embryos transferred.
Genetic testing can again help eliminate risks and mitigate the odds of an unsuccessful transfer. The majority—in one study, more than 61 percent—of miscarriages occur when the embryo has an abnormal number of chromosomes. A form of preimplantation genetic testing for aneuploidy (PGT-A or PGS) called comprehensive chromosomal screening (CCS) examines a small number of cells taken from the outside of an embryo created through IVF to determine if the embryo has the correct number of chromosomes before being transferred into the uterus.
“For embryos that undergo genetic testing, the transfer of a single embryo may be considered in all ages,” Dr. Styer says.
All that said, IVF still does not guarantee a baby. The Society of Assisted Reproductive Technology (SART) publishes the success rates of all member clinics, which you can search by zip code, and then compare to national averages. According to their most recent report (using data from 2015), 48 percent of women younger than 35 gave birth following IVF; just 3 percent of women older than 42 did. This data differs from that of the CDC, perhaps because birth rate reporting is inconsistent and unenforced. Their most recent analysis shows a 33 percent success rate for women age 34 or younger, with percentages decreasing from there.
In positive news, there are a few things you, the potential mom, can do to increase your chances of a healthy, happy baby following IVF: “Maintaining a normal body weight through a well-balanced diet and regular exercise, and avoiding tobacco and excessive caffeine and alcohol intake are the most effective and proven lifestyle modifications,” offers Dr. Styer.
Want extra credit? He also notes that acupuncture, mind-body therapy (like meditation), and dietary supplements (like a prenatal multivitamin, vitamin D3, Omega 3 fatty acid, and Coenzyme Q10) are also all measures that can be taken to help keep your body—and mind—healthy and strong before and during pregnancy.
Still have questions about getting pregnant? Check out our fertility FAQ here.
Editors’ note: We use the terms “woman” and “female” in this article to refer to people with internal reproductive organs; however we understand that not everyone with internal reproductive organs identifies as a woman or a female. We use the terms “man” and “male” to refer to people with external reproductive organs; however we understand that not everyone with external reproductive organs identifies as a man or a male.