• Posted February 23, 2024

1 in 3 Trans Masculine People Taking Testosterone Can Still Ovulate: Study

A third of trans masculine people who have undergone testosterone therapy and have stopped menstruating are still ovulating, a new study suggests.

That means they remain at risk for an unwanted pregnancy, despite the absence of periods, Dutch researchers concluded.

It's not clear why ovulation ceases for some transgender people under these circumstances, and why it may continue for others.

"Testosterone apparently has a heterogenous [varied] effect on ovarian tissue," said study lead author Joyce Asseler, a graduate student at Amsterdam University Medical Center. "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."

As Asseler explained in a university news release, "trans masculine people are people born female but do not identify as such, for example they feel male, gender fluid or non-binary."

In the new study, she and her colleagues examined the ovarian tissue of 52 transgender people who had had their ovaries removed after undergoing at least one year of testosterone therapy. Among trans masculine people, testosterone is a standard part of gender-affirming care.

The hormone typically causes menstruation to stop, and it's been assumed that means ovulation is also halted.

However, for a sizable minority of patients that may not be so: Examination of ovarian tissues showed signs of recent ovulation in 33% of samples tested, the Dutch researchers said.

Theoretically, that could mean that pregnancy is still possible among trans masculine people during this stage of their treatment, so contraceptives might be advisable, depending on the person's partner.

"The physical and mental consequences of an unplanned and unwanted pregnancy are enormous," Asseler said. "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," she added.

The study was published Feb. 22 in the journal Cell Reports Medicine.

More information

Find out more about transgender care at the University of University of California, Francisco.

SOURCE: Amsterdam University Medical Center, news release, Feb. 22, 2024