Early genetic testing may ensure babies are born hemophilia-free

For couples affected by hemophilia who want to avoid passing the inherited bleeding disorder to their children, early genetic testing — done during the in vitro fertilization (IVF) process — may offer a reliable option for family planning, a new study from Italy suggests.

That study investigated a procedure known as PGT-M, or preimplantation genetic testing for monogenic diseases, which is used to help identify healthy embryos created through IVF, a well-established assisted reproductive technology, and select them for transfer to a woman’s womb.

The researchers looked at 10 years of data from an Italian center and found that the use of PGT-M among couples undergoing IVF resulted in eight babies born free of hemophilia from a total of 26 embryo transfers. Of the 13 pregnancies that resulted, there were four miscarriages and one therapeutic termination in addition to the eight births, the team noted.

According to the researchers, this type of early genetic testing — before an embryo is implanted into a woman’s uterus during IVF — could give families an alternative to prenatal testing later on. It also could help reduce the likelihood that expectant parents will face difficult decisions about an affected pregnancy, the team noted.

“Our experience shows that PGT-M is a valid and reliable option for couples at risk of transmitting severe genetic diseases, enabling prevention of affected pregnancies and reducing the emotional burden linked to therapeutic abortion,” the researchers wrote.

The study, “Preimplantation Genetic Testing for Families at Risk of Haemophilia: Ten-Year Single-Centre Experience,” was published in the journal Haemophilia.

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Hemophilia is caused by mutations that reduce the activity of proteins needed for blood to clot, leading to prolonged and excessive bleeding. The condition can be passed from parents to their children.

Both hemophilia A and B are inherited in an X-linked pattern, meaning they mainly affect boys, who have only one X chromosome. Women, who have two X chromosomes, are usually unaffected or have milder symptoms. For carrier women, each pregnancy carries a 50% chance of passing the altered gene to the baby. Sons who inherit the mutation may develop hemophilia, while daughters may become carriers.

“The significant morbidity associated with severe hemophilia A has made prenatal diagnosis and PGT-M an attractive reproductive option for carrier females and their partners wishing to avoid having an affected child,” the researchers wrote.

8 babies born without hemophilia after early genetic testing

First developed in the 1990s, PGT-M allows embryos created through IVF to be tested for a specific inherited disease before they are transferred to the uterus. After eggs are fertilized in the laboratory, a few cells are removed from each embryo through a biopsy and analyzed. Only embryos found to be free of the disease are considered for transfer.

“Over the past three decades, PGT-M programs have been successfully implemented in numerous medical centres worldwide, providing an alternative to prenatal diagnosis and possible pregnancy termination for hemophilia carrier couples,” the researchers wrote.

Here, a research team in Milan reviewed their experiences with the procedure after changes in Italian law allowed embryo genetic testing for couples at high risk of passing on inherited diseases. The data, from 2015 to 2025, came from the Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, in collaboration with Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico.

During that period, 23 couples contacted the center to learn about the PGT-M program. Altogether, 19 completed multidisciplinary counseling and genetic evaluation, while 15 couples — 11 affected by hemophilia A and four by hemophilia B — ultimately underwent PGT-M.

Our ten-year experience with PGT-M confirms that this technique represents a reliable reproductive option for couples at risk of transmitting X-linked disorders such as hemophilia.

The women carrying the disease-causing mutation had a mean age of 34.6. Of the 15 couples, eight underwent a single PGT cycle, while seven underwent multiple cycles, ranging from three to seven.

Overall, 69 embryos created through IVF reached the blastocyst stage, the point at which embryo biopsy is typically performed. A definitive genetic diagnosis was obtained for 58 embryos (84%), and 72% were unaffected by hemophilia and suitable for transfer.

Of the 26 embryo transfers, 13 resulted in a pregnancy — an implantation rate of 50% per embryo transferred, the researchers noted. Eight pregnancies resulted in live births, seven girls and one boy, while four ended in miscarriage and one was terminated after prenatal testing identified an unrelated chromosomal abnormality. All babies born were free of hemophilia.

Three couples also chose prenatal testing during pregnancy, and in every case, the results confirmed the PGT genetic analysis, providing additional evidence for the accuracy of the PGT-M, the team noted.

“Our ten-year experience with PGT-M confirms that this technique represents a reliable reproductive option for couples at risk of transmitting X-linked disorders such as hemophilia,” the researchers wrote.

“Furthermore, it can inform couples about the health of their embryos before pregnancy begins, minimizing the risk of transmitting severe genetic disorders, reducing the need for pregnancy termination in case of an affected fetus, and alleviating the emotional burden associated with such procedures,” the scientists concluded.