Want kids one day? Take the quiz

Here's why you should track your fertility over time

4 min read

There are lots of things that influence your body's ability to get pregnant and bear a child that you can't change, like your age and medical history. Hormones, though, do change (even throughout the day!), and that's why it's important to keep regular track of what they're up to.

Maybe you've just started thinking about investigating the status of your fertility hormones. Maybe you've even taken the Modern Fertility test already, and discussed the results with your doctor. (We love it!) Whether you're about to jump into learning about your fertility or you've already gathered some vital info, we're here to tell you that there's more to fertility than just a single snapshot! What does that mean? Read on.

Wait - what hormones are we even talking about?

The hormones we're zeroing in on in this piece are those most directly associated with your fertility. Modern Fertility's test can evaluate anti-Mullerian hormone (AMH), prolactin (PRL), follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), thyroid-stimulating hormone (TSH), and free thyroxine (FT4). These hormones can provide you and your doctor with insight as to your ovarian reserve (how many eggs you have), ovulation, physical health, and anything that might impact your future fertility. (A reminder here that the test cannot diagnose you as infertile.) And yes - If you're on hormonal birth control, you can still take the test.

What do we mean when we say that hormones change over time?

All hormones change, but they don't all change in the same way, or for the same reason. Menopause and the menopause transition will impact all of these hormones: FSH starts rising as you get closer to menopause because you need more of it to get your follicles (egg sacs inside your ovaries) growing, and there are fewer follicles as you get older. E2 declines only when women hit the menopausal transition, because those same follicles produce E2, and since you're operating with fewer follicles, there's less E2. LH increases as you reach the menopausal transition, and then decreases after menopause. Prolactin stimulates milk production after birth and can put a pause on ovulation while you're breastfeeding. It changes during and after pregnancy, and your levels can be too low or too high, so you do want to test these over time so you know they're in the right range. The levels of your thyroid hormones — thyroid stimulating hormone (TSH), free thyroxine (FT4) — should remain steady, unless you are diagnosed with an under or overactive thyroid or an autoimmune disease that affects thyroid function. Prolactin and TSH can also fluctuate throughout the day (this is called diurnal variation) and are usually higher in the morning. FSH, LH and E2, which regulate your menstrual cycle, fluctuate throughout the month. AMH (see below) is the only hormone that declines steadily over time.

For example: AMH

Let's take a closer look at AMH (anti-mullerian hormone), and how it behaves over time. AMH is produced by the cells in your follicles. Your levels of AMH indicate how many eggs you have remaining, and that amount is known as your ovarian reserve. If you have a high level of AMH in your blood, you probably have a high ovarian reserve. It's not an indicator, however, of the quality of those eggs.

AMH levels decline with age. The median AMH level for 18 - 25 year olds, for example, is 3.6 nanograms/milliliter (ng/ml). It's possible to be 25 and have a low AMH level, which indicates a depleted ovarian reserve. By the time she's 35, though, a woman will likely have an AMH level between 2.47 and 1.71 ng/mL . Your AMH levels can also be a predictor (but not a cause) of menopause, since it can be very low, sometimes even undetectable, in the five years before menopause is reached. Factors such as genetics and smoking can lower the age of menopause, and your AMH values will reflect this.

Tracking AMH over time can tell you if your levels are average, high (this can indicate the presence of PCOS) or low. Having a sense of when you could expect to hit menopause, for example, can help you plan your kid timing. Based on what you learn and discuss with your doctor, you might decide to freeze your eggs (AMH levels can indicate how you might respond to ovarian stimulation, which is done during the egg freezing process to retrieve eggs, adjust your timing, or keep it as is.

So how often should you test, and why?

The physicians who advise us here at Modern Fertility recommend testing every 12 months if you're not trying to get pregnant. This can vary, though, depending on a few things. If you're transitioning off of hormonal birth control or have had any other major health changes, you can test sooner to determine how your hormone levels have changed.

You're testing to make sure your hormones, even those that don't dip over time, are tracking as they should. You want to keep an eye out for steep declines in AMH, for example, to make sure there are no steep declines that would indicate that your ovarian reserve is decreasing faster than expected which may result in updating your timing. The idea here is that you'll have the information about your fertility hormones that you need to make decisions with your doctor about your future before you start trying to conceive.

Modern Fertility's test can arm you with information about your hormones, but it's not "just" a test — you'll have access to a community of health care professionals who can answer your questions, as well as other people who have taken the test and want to talk about it! Finally, there's our Timeline Tool, which you can use to see how your plan for having kids could play out when you factor in your age, desired number of children, time between them, and your hormones. We want you to have all the information you can before you take the leap. Don't settle for hypotheticals when it comes to the future — get to know what your body is up to now.

Did you like this article?

Chanel Dubofsky

Chanel's writing has appeared in Cosmo, Rewire, Lilith, HelloFlo, & Extra Crispy. She has an MFA in Fiction from Vermont College of Fine Arts & lives in New York. Follow her @chaneldubofsky.

Join the Modern Community

This is a space for us to talk about health, fertility, careers, and more. All people with ovaries are welcome (including trans and non-binary folks!).

Recent Posts

Why does vaginal lubrication matter for sex?

Lube 101: what it is, why to use it, and how to choose the best lube for you

What every female athlete should know about exercise and reproductive health

The Modern guide to ovulation predictor kits and ovulation tests

How to choose the right birth control for you