One-third of trans masculine individuals taking testosterone have recently ovulated. This means that they can still get pregnant. If they are sexually active, they should be mindful of this and use contraception. This research by Amsterdam UMC, conducted in collaboration with LUMC, was published today in Cell Reports Medicine. 

"Trans masculine people are people born female but do not identify as such, for example they feel male, gender fluid or non-binary. Our examination of their ovarian tissue shows that 33% of them show signs of recent ovulation, despite being on testosterone and no longer menstruating," says Joyce Asseler, PhD candidate at Amsterdam UMC.  

Trans masculine people often use hormone treatment with testosterone to masculinize physically. This hormone usually stops them from menstruating. In that case, it is often assumed that ovulation does not take place. 

Physician-researcher Joyce Asseler and gynecologist Norah van Mello examined the ovarian tissue of transgender people who had their ovaries removed as part of their gender-affirming treatment. They had all used testosterone for at least 1 year prior to and at the time of the procedure. Their analysis shows that 17 of the 52 study participants (33%) show signs of recent ovulation in the ovarian tissue.  

"Testosterone apparently has a heterogenous effect on ovarian tissue. We don't know why one person ovulates and another person doesn't. In any case, we cannot explain this difference by the type of testosterone, or how long someone has been taking testosterone," says Asseler.  

People who ovulate can, in theory, also get pregnant. This also applies to these trans people. For them, it is therefore necessary to use contraceptives if they are sexually active with someone who produces sperm cells. "The physical and mental consequences of an unplanned and unwanted pregnancy are enormous. It is important that trans masculine people and their healthcare providers are aware of this risk and act accordingly. Furthermore, this discovery can contribute to better care for trans masculine people who experience abdominal cramping," concludes Asseler. 

Read the full article here in Cell Reports Medicine.