Does Mounjaro affect fertility? Here's what to know

If you've been wondering about how weight loss medications affect fertility, a quick glance at Reddit will let you know you're not alone.

Everyone has their own unique reasons for beginning a weight loss journey; for some people, reproductive health is at the front of their minds when starting their weight loss treatment.

If you've been thinking about fertility planning, getting pregnant soon, or just want to know how weight loss drugs might affect your birth control, you've come to the right place.

Full disclaimer: the research in this area is still pretty new (and ongoing), but we're here to share what we currently know.

Does Mounjaro affect the menstrual cycle?

Currently, there's limited data on whether taking Mounjaro affects your menstrual cycle — no studies have given us a definite answer just yet.

A lot of the current research has looked at how Mounjaro treatment might help women living with polycystic ovary syndrome (PCOS), and some of the studies look promising.

More clinical trials are needed before we can generalise about whether weight loss medications have an impact on menstruation [1].

How weight can affect your periods

Having said this, what we do know for sure is how weight loss and maintaining a healthy weight can affect your periods.

Being overweight or living with obesity can significantly disrupt menstruation, causing symptoms such as [3]:

• Irregular periods
• Increased risk of premenstrual dysphoric disorder (PMDD) and/or premenstrual syndrome (PMS)
• Heavy bleeding

Carrying excess body weight is also linked to high blood sugar, insulin resistance, and hormonal imbalance. Interesting science-y fact: fat cells can actually create the hormone oestrogen [4]!

For women who are overweight, these cells grow and release more oestrogen — which can eventually trick the body into thinking it's taking birth control or pregnant. This can stop ovulation, and lead to periods stopping or becoming irregular [4].

Insulin resistance occurs when the body stops responding well to insulin — the hormone that regulates blood sugar.

The pancreas then starts going into overdrive: making too much insulin, and throwing off both hormones and blood sugar levels. When all of this goes out of whack, so does your cycle [5][6].

In some cases, losing weight can mean a healthier, more regular cycle. Maintaining a healthier weight can also improve insulin resistance and hormonal balance [4].

On the other hand, extreme weight loss or losing weight too quickly can also affect your hormones — leading to irregular or missing periods. Without enough nutrients and body fat to support hormone health, your periods can stop coming altogether [4].

Being underweight can make your oestrogen levels too low and cause you to stop ovulating. No ovulation? Welcome irregular cycles, or periods stopping altogether [4].

TLDR? While weight loss medication isn't directly linked to menstrual cycle changes, weight loss or gain can affect your cycle. If needed, weight management might make your cycle more regular, and improve other negative symptoms [5].

The link between Mounjaro and fertility

Similar to the above, there's not a huge amount of data yet on whether Mounjaro directly influences fertility.

There are lots of anecdotal stories and articles online about women becoming pregnant after weight loss treatment, but the scientific evidence for why this might happen is still being established. The relationship between weight and fertility is much more well-researched.

Before we discuss that further, there are 2 really important things to remember:

• The relationship between fertility and weight is complex and very individual. Always chat to your GP or healthcare provider if you need health advice tailored to you.
• Weight loss isn't recommended during pregnancy. If you're taking weight loss medications and thinking of becoming pregnant, or have recently found out that you're pregnant, make sure to get medical advice as soon as possible [7].

Can losing weight improve fertility?

As we mentioned earlier, excess body weight can interrupt menstruation and hormone balance — which makes it harder to get pregnant.

But there are actually multiple ways being overweight can influence fertility. These include [8]:

• An increase in male hormones (called hyperandrogenemia) which disrupts ovulation
• Problems with how your body produces hormones in the first place
• Issues with metabolism (which can affect ovarian function)
• Poorer egg quality and less chance of fertilisation

The 'ideal' weight for getting pregnant varies for everyone, but it's clear being overweight (or underweight) leads to reduced fertility — making it harder to conceive naturally [8].

Excess body weight can also make fertility treatment harder. All of the above factors decrease the chance of success, as well as make egg retrieval more difficult.

Finally, it can mean fewer viable embryos and more risk of complications during treatment [8].

With all this in mind, healthy and sustainable weight loss can help improve fertility outcomes. When weight loss injections like Mounjaro are part of a holistic treatment plan, they can help you reach your goal weight. Theoretically, this means they can help increase the chances of becoming pregnant [9].

Research shows that even 5% weight loss can improve fertility. Reaching a healthier weight increases the likelihood of ovulation and conception — whether you're trying to conceive naturally or going through fertility treatment [8].

How does weight influence pregnancy outcomes?

Women who are overweight or living with obesity are also more likely to experience pregnancy complications.

There's a higher risk of certain health conditions and other complications, including [10]:

• Gestational diabetes
• Preeclampsia (high blood pressure)
• Preterm birth and stillbirth
• Problems with how the baby develops in the womb
• More likely to require caesarean section and induced birth
• Bleeding, anaesthetic complications, and wound infections

According to the research, being overweight also leads to an increased risk of miscarriage. This can be linked to hormonal imbalances that affect the implantation of embryos, or make it harder to maintain a healthy pregnancy.

Some studies suggest that obesity-related inflammation can also contribute to this risk [10].

We know this is a lot to take in, but the good news is a lot of these risks can be reduced or avoided. If you're planning a pregnancy, weight loss can increase the chances of it being a healthy journey for you and the baby [10].

Is Mounjaro safe when trying to conceive?

Now that we've covered how Mounjaro might affect fertility and pregnancy, what about if you're in treatment and decide it's baby time?

At this stage, there haven't been enough studies to know how Mounjaro affects pregnant people, or how it can impact a developing foetus. It's also unknown whether the medication can be passed on through breast milk [7].

While there haven't been any human studies, animal studies suggested exposure to Mounjaro in pregnancy might increase the risk of birth defects and low birth weight. Weight loss isn't recommended during pregnancy either, because of the risk of harm to the baby [7].

For these reasons, most doctors and health experts recommend stopping Mounjaro treatment for at least 2 months before becoming pregnant. This allows time for the medication to leave your system and reduces any potential risks [11].

This doesn't mean you should panic and stop your treatment cold turkey — it's always best to chat about a transition plan with your doctor or healthcare provider. This is especially important for anyone taking Mounjaro for diabetes management; your doctor will need to discuss your individual needs with you [11].

Of course, not every pregnancy is planned and sometimes things happen. It's important to know that Mounjaro can affect the efficacy of oral birth control pills [7].

If you're taking oral birth control and don't want to become pregnant, it's recommended to add a barrier method of contraception (e.g. condoms) or consider non-oral contraceptives for at least a month after starting Mounjaro, and after each dose increase [7].

If you're in doubt about your birth control options or want more information about how to prevent pregnancy while you're taking Mounjaro, make sure to chat with a health professional.

Because of the safety concerns listed above, if you do become pregnant while you're taking Mounjaro, you should contact your healthcare provider as soon as possible.

They'll be able to help you safely transition off the medication, check in on how things are going, and make sure you get any pregnancy-related care you need [11].

You might be decorating a nursery as we speak, considering your options and planning, or proudly child-free. If you need more information about Mounjaro, pregnancy, and birth control, feel free to get in touch with our team.