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Diagram of testosterone molecule and a circle showing the menstrual cycle with a star indicating the day of ovulation.

Illustration by Marta Pucci

Cycle A-Z

How testosterone therapy affects fertility

First up: it’s not birth control

by Nicole Telfer, Science Content Producer; and Jen Bell, Writer
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Top things to know

  • Testosterone is not a form of birth control

  • Some people (including some healthcare practitioners) incorrectly think that taking testosterone is a form of contraception

  • Testosterone may cause birth defects to a fetus

Many transgender men and nonbinary or genderqueer AFAB (assigned female at birth) people take testosterone as a form of gender affirmation therapy.

Some people believe that if you take testosterone you can’t get pregnant, but this is not true. Testosterone is not a form of birth control.

We don’t yet know much about the complex hormonal relationships going on within the bodies of AFAB people on testosterone. Relatively few trans men have become pregnant and given birth. The science of gender affirming hormonal treatments and surgeries is quite new, so there is still much to learn.

Here is the most up-to-date knowledge about testosterone therapy and the possibility of conception. Most of it comes from small studies, surveys, and expert opinions from specialists in the trans health and reproductive field. More large scale research is needed.

What to know before starting testosterone therapy

Transitioning is a big and exciting decision which will affect the rest of your life. Before choosing to hormonally or surgically transition, you may want to consider fertility-preservation options, such as egg and embryo freezing (1,2). If you want the option to have genetically-linked children in the future, but are unsure about carrying them, talk with your healthcare provider about your fertility options.

If you already started using testosterone and want to preserve your fertility freezing eggs or embryos may be an option. A Swedish study on a small group of trans men who underwent fertility preservation therapy to harvest and freeze their gametes (eggs) demonstrated that this is possible (3). Seven of the men were on testosterone before they started their fertility preservation therapy. They had to stop taking testosterone, wait for their period to restart, and begin additional hormonal treatments (3). While this fertility preservation therapy was capable of retrieving and freezing eggs, the changes were distressing for some of the participants who found the restoration of menstruation, gynecological exams, and being naked particularly difficult and stressful (3).

Testosterone and pregnancy

Testosterone is not a form of birth control (4,5). Even AFAB people who have been on testosterone for a while and who no longer have periods can still get pregnant.

In a survey of 41 trans men who became pregnant and gave birth, 61% of participants had used testosterone before becoming pregnant (6). Three quarters of these pregnancies were planned, meaning that one quarter of these pregnancies were unplanned (6). This highlights the fact that taking testosterone is not a form of birth control. Trans men and AFAB nonbinary people who have not had a hysterectomy (removal of the uterus) or oophorectomy (removal of the ovaries) should continue to use contraception if they are having penis-in-vagina sex and want to avoid pregnancy.

Of the trans men using testosterone who planned their pregnancies, once they stopped taking testosterone 20% became pregnant before menstruation returned, while the rest regained their menstruation within the next 6 months (6). Most of the trans men (76%) regained menstruation within three months of ceasing testosterone (6). Prior testosterone use did not affect their chances of having a healthy pregnancy or birth compared to a cisgender (non-trans) woman (6). Most trans men who previously used testosterone conceived within six months, though 44% did use medical interventions like fertility medications and assisted reproductive technologies (6).

Another study looked at the ovary structure of 40 transgender men who had been taking testosterone for more than one year on average (7). In 35 of the trans men studied, their eggs were going through a “normal maturation process” in preparation for potential ovulation. These results were similar to a previous study of cisgender women (7,8). This shows that taking testosterone does not stop the process of follicle development, which is part of the body’s preparation for ovulation.

Testosterone and conception: things we don’t know

It’s important here to pause and think about the people who were not included in this questionnaire—such as trans men on testosterone who wanted and tried to become pregnant, but could not. The previous study only focuses on people who actually conceived. We don’t know what percentage of people were unable to conceive after stopping testosterone therapy, or if this differs from infertility rates among the cisgender female population. Some researchers warn that some people may not be able to resume ovulation after stopping testosterone use, and this may depend on their age and how long they've been using testosterone (1). More research is needed.

Using birth control while on testosterone

If you are taking testosterone and have not had a hysterectomy (removal of the uterus) or oophorectomy (removal of the ovaries), then you need to use contraceptives if you are having penis-in-vagina sex.

The American College of Obstetricians and Gynecologists (ACOG) recommends that trans men who have the potential to become pregnant should be offered all forms of contraception, just the same as cisgender women (4). This means that trans men can take hormonal birth control, even if they are taking testosterone at the same time. There are no known interactions or contraindications (4).

According to ACOG, many transmasculine patients chose to use progestin-only contraceptive methods, like the hormonal IUD, the contraceptive injection, or the contraceptive implant (4). Periods can be a source of gender dysphoria for some people, and testosterone does not always cause menstruation to stop immediately. Copper IUDs can also be an option for trans people on testosterone who want to avoid additional hormones, but it's only recommended for people whose periods have stopped (4).

In a 2016 US survey of trans men, 3 in 5 reported using contraception either currently or in the past, with condoms being the most popular form of birth control, followed by the contraceptive pill in second place (9). The idea that testosterone is a contraceptive is common, with 16% of trans men in the study reporting that they used testosterone as a contraceptive, and 5.5% them were recommended testosterone as a contraceptive by their healthcare provider (9).

Trying to conceive after testosterone therapy

If you are taking testosterone and want to become pregnant, it’s important to talk to your healthcare provider about stopping testosterone. Testosterone is actually teratogenic (meaning it can cause birth defects) to a fetus. If you are taking testosterone and think you may be pregnant, speak to your healthcare practitioner as soon as possible. If you are pregnant, avoid starting testosterone, as it will harm the developing fetus (5).

Working with a healthcare provider, some time may be needed to restore normal ovulation and menstruation, and additional medical interventions may be required for your desired pregnancy (6).

Although more research is needed, we do know that it’s possible to get pregnant while taking testosterone. Whether you want to avoid pregnancy or are trying to conceive, we recommend you discuss your needs with your healthcare provider, and plan accordingly.

We’ve published information about testosterone and your menstrual cycle, and trans and nonbinary people’s experiences with birth control. Len Lukowsi wrote about his experience with a pregnancy scare as a trans man, and Elliott Cennetoglu shared their thoughts on pregnancy when you’re trans.

Learn how to find a trans-friendly doctor, and get tips for getting better healthcare when you’re trans, nonbinary, or genderqueer.

Check out our guide to tracking your period when you’re trans, and download Clue to learn about your cycle.

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