Does genetic testing improve IVF outcomes?

This study looked at the effect of preimplantation genetic testing (PGT) on in vitro fertilization (IVF) outcomes for women with a poor ovarian response (POR). It found that PGT led to similar birth rates, but there were fewer miscarriages.

The first step of the infertility treatment IVF is to stimulate and collect multiple oocytes (eggs). Women who do not produce many oocytes in response to the ovarian stimulation medications are said to have a poor ovarian response (POR). Infertility treatment can be more difficult for women with POR. In addition, many women with POR are also over age 35 and are at increased risk for embryos
with aneuploidy. Aneuploid embryos have an unusual number of chromosomes (pieces of genetic material). Pregnancies with aneuploid embryos most often end in miscarriage. Down syndrome and certain other birth conditions are also caused by aneuploidy.

Preimplantation genetic testing for aneuploidy (PGT-A) is a method of testing IVF embryos prior to embryo transfer. PGT-A can select better quality embryos, leading to fewer miscarriages and more live births per embryo transfer. However, fewer embryos reach the stage to transfer when PGT-A is used. Women with POR may have few embryos available, to begin with. It is unclear how PGT-A affects IVF outcomes for women with POR.

This study used records of women with POR who were undergoing IVF. All patients had four or fewer oocytes retrieved. Patients decided whether to have PGT-A after discussing the choice with their doctors. 165 patients chose to use PGT-A. Because some patients underwent more than one cycle, there were 241 PGT-A cycles. 96 patients underwent 112 cycles without genetic testing (non-PGT). The two groups had similar ovarian reserves as measured by the anti-Mullerian hormone (AMH).

Significantly fewer PGT-A cycles led to an embryo transfer (13.7% vs. 70.6%). 21.9% of the embryos tested with PGT-A had a normal number of embryos. Among embryos that were transferred, significantly more PGT-A transfers led to pregnancy (50.0% vs. 12.7%) and live birth (47.1% vs. 7.6%). PGT-A pregnancies had a significantly lower rate of miscarriage (3.6% vs. 40%).

The total pregnancy rate per egg retrieval cycle was similar between the two groups (7.1% – PGT-A; 8.9% – non-PGT). The live birth rate per egg retrieval was also similar between the two groups (6.6% – PGT-A; 5.4% – non-PGT). However, among women over age 38, PGT-A cycles led to more live births (5.5% vs. 0%).

For women with POR, the overall birth rate was similar with and without PGT-A. PGT-A may improve birth rates for women over age 38.

This study had a small number of patients and was retrospective (used medical records). Also, patients who chose PGT-A may have differences from those who did not choose PGT-A. More studies are needed.