Authors: Dr. Sav Zwickl and Dr. Alex Wong.
Content Warning: This article contains descriptions and images of genitals. We also reference menstruation (periods), sexual activity, and other sexual health topics. When referring to specific parts of the body, we use anatomical/medical terms e.g., clitoris, vaginal canal.
Note: Not all people want the same changes from using testosterone and not all bodies will respond the same to hormone therapy. All of the body changes described in this article are typical but not universal. Lower doses of testosterone and lower levels of testosterone will likely impact the rate of changes, and whether some changes occur at all.
Image credit: Gender Spectrum Collection.
What effects does testosterone have on the genitalia, uterus, and ovaries?
When trans and gender-diverse people presumed female at birth start testosterone therapy, one of the first changes they often report is to their genitals. Within weeks, some people notice an increase in the size of their clitoris and report it becomes more erect during arousal. It starts looking and behaving more like a penis (see diagrams below). Within the trans community, this is often called ‘lower growth’ or ‘bottom growth’. Sometimes this rapid growth comes with physical discomfort or even pain. While some people find this growth occurs mostly in the first year of starting testosterone, others report growth spurts years into using testosterone.
These diagrams were designed by Katja Tetzlaff and were sourced from: https://www.folxhealth.com/library/testosterone-bottom-growth
Internally, there are changes too. While some people experience an increase in vaginal lubrication, dryness (known as vulvovaginal atrophy) is very common. Atrophy may include dryness of the vaginal canal even with arousal, and a thinning and weakening of the walls of the vagina, meaning that tearing and bleeding become more common with vaginal penetration.
For those who had periods prior to starting testosterone, regular bleeding typically stops within the first six months of hormone therapy. However, breakthrough bleeding is not uncommon, even after years of using testosterone. Changes to the endometrium (the lining of the uterus) vary, and no major changes appear to occur in the ovaries. Testosterone typically puts a halt to the hormones that mature eggs in the ovaries, and the ovaries go into ‘hibernation’, meaning those using testosterone may not ovulate.
Even without regular periods, some people using testosterone still ovulate, and pregnancy remains a possibility. It is important for people to consider contraceptive measures if they are engaging in sexual activity where pregnancy may occur. Grunt and Transhub provide trans-specific information on safe sex.
I have heard that some people using testosterone experience pelvic pain. How common is it?
Pelvic pain is extremely common in the general population (up to 81% report painful periods and up to 24% report pain not related to their periods). Given that this pain is most often related to menstruation (i.e., painful periods), it has been perplexing to see increasing numbers of trans people whose periods have stopped on testosterone, seeking treatment for pelvic pain.
To try and get a better understanding of what might be going, we recently surveyed nearly 500 trans and gender-diverse people using testosterone about their experiences of pelvic pain before and after starting hormone therapy. Almost three in four respondents (72%) reported experiencing pelvic pain when using testosterone. Another recent survey also found a similar prevalence rate; however, in both cases, responder bias means this figure is likely an overestimate (i.e., people with pelvic pain were more likely to participate). The true figure remains unclear.
It is important to note that almost every person (98%) who reported pelvic pain after starting on testosterone, also reported experiencing pelvic pain before starting testosterone (e.g., period pain, pain around ovulation). On a scale from 0 (no pain) to 10 (most severe pain), the median rating of pelvic pain in those using testosterone was 6.2. This is slightly lower than the median score of 6.7 reported for period pain severity prior to commencement of testosterone.
For most people, pelvic pain after starting testosterone is experienced ‘sometimes’, though one in ten reported ‘always or almost always’ experiencing pain. Pelvic pain was mostly described as ‘cramping’ (73%), followed by ‘aching’ (58%) and ‘stabbing’ (40%). The pain was most often located in the hypogastric region (87%) (the lower-middle section in the diagram below).
This diagram was featured in our peer-review publication in LGBT Health.
What causes pelvic pain in people using testosterone?
In our survey, we looked at the differences between those people who reported pelvic pain and those who didn’t, in order to determine any factors that increase the risk of pelvic pain.
Our findings indicate that pelvic pain is more likely in those people whose periods have not stopped on testosterone. It is likely that persistent bleeding in people using testosterone is driven by rises and falls in estradiol and progesterone concentrations over the course of a menstrual cycle. If this is the case, pelvic pain may be driven by similar factors as ‘period pain’, including contractions of the uterus, and hormonal changes to the pelvic floor muscles.
In our survey, pelvic pain was also associated with pain with orgasm, but not associated with pain with penetrative sexual activities or when touching the external genitalia. The increased likelihood of people with ongoing periods and pain with orgasm reporting pelvic pain, suggests that testosterone therapy might result in high pelvic floor muscle tone (the pelvic floor muscles are tense, inflexible, or even spasm).
We didn’t find an association between having pelvic pain and body size, reporting genital dryness, having an IUD, or having had previous pregnancies (including abortions or miscarriages). Likewise, diagnoses of endometriosis, vulvodynia, or vaginismus did not increase the risk of pelvic pain.
Mental health can also affect experiences of pain. Consistent with other research showing a clear association between chronic pain and post-traumatic stress disorder (PTSD), we also found that those with a current or previous history of PTSD were more likely to report pelvic pain after starting testosterone. We didn’t find an association between pelvic pain and depression or anxiety.
What are the treatment options for pelvic pain in people using testosterone?
In our survey, over half of the people experiencing pelvic pain after starting testosterone found ‘pain-killers’ useful for relieving pelvic pain. Non-steroidal anti-inflammatory drugs (e.g., Ibuprofen, Diclofenac and Aspirin) and paracetamol appear to be the most helpful.
Localised oestrogen treatments such as Vagifem are typically effective in treating vulvovaginal atrophy, which may, in turn, reduce pelvic pain. Lubricants are also useful for sexual activity, in reducing the risk of tearing and pain during sexual activity.
For people who experience persistent periods when using testosterone, common treatment options include intrauterine devices (IUD) and progesterone tablets or implants.
There were only 26 people in our survey who had undergone hysterectomy (surgical removal of the uterus) which makes it hard to assess whether hysterectomy is a useful treatment or not. Despite the limitations of small numbers, 72% reported a reduction in pelvic pain but 20% reported little to no change in their pelvic pain and two reported an increase in pelvic pain following hysterectomy. Further research is needed to determine how effective hysterectomy is in treating pelvic pain in people using testosterone.
Given the possibility that high pelvic floor muscle tone may cause pelvic pain, pelvic floor physical therapy to relax the muscles, may be a beneficial treatment option to try. Psychological treatments to address psychological factors such as PTSD may also be useful.
Given that the exact cause/s of pelvic pain are still unknown, multiple different approaches may be needed to address the contributing factors. This may involve some trial and error to establish what is the most effective treatment for each person.
The full peer-reviewed publication is available in LGBT Health.