People transitioning female to male face issues around future fertility. But new research suggests children in the future are a real possibility for these transgender men.
Now, research shows that transgender men can remain fertile after even one year of testosterone treatment.
Ovarian function well-preserved
It's common for transgender men – who were assigned as female at birth (AFAB), but who identify as male – to undergo testosterone therapy as a gender-affirming treatment. But some may later want children through their own pregnancy or via surrogate, the Israeli researchers explained.
"Because the long-term effects of testosterone therapy on fertility are unknown, the current recommendation is to stop testosterone at least three months before fertility treatments," said lead investigator Dr Yona Greenman. She heads the Transgender Health Center at Tel Aviv-Sourasky Medical Center.
The study included 52 transgender men, aged 17 to 40, who received testosterone therapy over 12 months. They had the expected increase in testosterone blood levels and decrease in oestrogen, but their levels of anti-Mullerian hormone (AMH) remained in the normal range for fertility.
AMH levels are used to appraise remaining eggs in the ovaries. Average levels in study participants decreased only slightly, suggesting their ovarian function was well-preserved, according to Greenman.
Participants also showed no changes in the thickness of their uterine lining. A thick lining is crucial for embryo implantation and a successful pregnancy.
Reproduction a transgender right
The findings are to be presented Saturday at the Endocrine Society's annual meeting, in New Orleans.
"Our research shows for the first time that after one year of testosterone treatment, ovary function is preserved to a degree that may allow reproduction," Greenman said in a meeting news release. "This information is important for transgender men and their partners who desire to have their own children."
She said more study is needed to examine the effects of testosterone on other benchmarks of fertility, including the quality of eggs and embryos fertilized in vitro.
"These results are a further step toward providing transgender people basic rights such as reproduction," Greenman added.
Research presented at meetings is typically considered preliminary until published in a peer-reviewed journal.
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