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When should women start thinking about their future fertility?

Is it ever too early to start thinking about your future fertility?

Did you know that women are born with their entire lifetime supply of eggs? At birth, a girl's ovaries contain approximately 2 million eggs; this decreases monthly, and by puberty, only 25% of her egg pool remains (1).

In our 20s, thinking about our fertility is probably not uppermost in our minds – we just take it for granted that by the time we want children, we'll be able to have them. But as we approach our early to mid-30s and are wrapped up in careers and just getting on with life, many women start to have nagging doubts about whether they could be leaving it too late to start a family. Let's look at why it's so important to plan ahead and how you can make the right choices now. 

Firstly, it's important to understand how fertility works. Female fertility is predominantly measured by the quantity and quality of a woman's eggs, and as mentioned, this supply is continuously declining. Each month one dominant egg is stimulated by hormones; it matures and then travels down to the uterus. This egg has 48 hours to be fertilised; otherwise, it dies, and the cycle begins again. 

When to conceive is entirely a woman's choice, but unfortunately, nature also has a say in this decision, with fertility declining steadily after the age of 30. Research shows that in recent years, more women are waiting to start a family (2). This could be for a multitude of reasons, such as pursuing a career or waiting to find the right partner, but regardless it is necessary to consider all the implications. The upside of delaying pregnancy is that you have more life experience and will probably be in a better financial position; however, it also has its risks. Although we all know many women who conceive in their late 30s and even their early 40s, delaying pregnancy into their late 30s can leave some women disappointed. There is no 'correct age' to have a baby, and unfortunately, not all women have a straightforward path to motherhood. It's important to think about when you want to start a family and prepare for all the possible outcomes. 

Wouldn't it be great if there was a crystal ball that helped you know whether you could afford to wait to start a family or whether you should be getting on with it now? Unfortunately, there is no single test that will predict your fertility, and even if there were, there are so many other factors that may affect a couple's ability to conceive a child. However, our new Future Fertility Blood Test measures three separate hormones, which together can provide some insights into whether you are heading towards menopause, and whether your egg supply (ovarian reserve) is normal for your age. The test is performed at the start of your menstrual flow. It measures follicle-stimulating hormone (FSH), oestradiol, and anti-mullerian hormone (AMH), which can determine whether your ovarian reserve is declining and if any age-related changes have begun. 

Let's take a look at each of these hormones in turn:

Follicle-Stimulating Hormone (FSH) 

A follicle is a small sac inside the ovary, within which an egg will mature. Follicle-stimulating Hormone (FSH) is a hormone made in the pituitary gland which controls the menstrual cycle and egg production. As the number of viable eggs decline over a woman’s lifetime, so the number of eggs which respond to FSH decreases. The amount of oestradiol produced by them also falls, which signals to the pituitary gland to make more FSH to try to stimulate egg production. Therefore, high levels of FSH may suggest that your body is struggling to make eggs and is trying to compensate. High FSH is typically seen in menopausal women, but it is worth noting that FSH levels can vary extensively during the perimenopause (the years preceding menopause), being normal one month, and high the next as the menopause nears.


Oestradiol is a steroid hormone that is produced in the ovaries. It is responsible for maturing and releasing an egg for fertilisation and preparing the uterus for implantation. Oestradiol levels decline as you get older so that by the time you reach menopause, your oestradiol levels will be a fraction of their peak levels. Low oestradiol, together with elevated FSH, can indicate that you may be becoming menopausal. During perimenopause oestradiol, like FSH, can fluctuate hugely. A single low oestradiol or high FSH result may not be significant, and also may not mean that you can't conceive. However, it may be a sign that your body is starting to transition into menopause.

Anti-mullerian hormone (AMH)

AMH is a hormone created by follicles within your ovary, which helps to predict egg yield. The more eggs/follicles you have, the higher the anti-mullerian hormone level is likely to be (6). Measuring AMH can help to diagnose premature ovarian failure and is used by fertility clinics to assess the likelihood of a successful egg retrieval. High AMH levels can also be caused by polycystic ovaries, and there is ongoing research into how this could be used to diagnose polycystic ovary syndrome. For women interested in their future fertility, it can help guide them in family planning. Anti-mullerian hormone is not a precise measure of how many viable eggs a woman has and should only ever be used as a guide. We suggest that a low AMH result should be followed up with an antral follicle count scan where a doctor counts the number of activated follicles in the ovaries. 

Our Future Fertility Blood Test can help to assess the number of viable eggs remaining in the ovaries. It is not a predictor of fertility, as so many factors can affect conception. However, understanding whether your hormones and egg quantity are normal for your age can help you in family planning. You may decide that you don't have time on your side and may even consider egg freezing if your ovarian reserve is lower than you hoped. Or you may decide that you can afford to wait while you get on with your life. No woman has unlimited time to have children; our Future Fertility test can help you in the choices you make today.


1. Rogelcancercenter, (2020). Normal Ovarian Function. [online] Available at: [Accessed 04/02/20]. 
2. Baptiste, N. (2014). While Waiting for a Life Partner: Wisdom Keys for Single Christian Women. Indiana: AuthorHouse, Pg 92. 3. Waggoner, M. (2017). The Zero Trimester: Pre-Pregnancy Care and the Politics of Reproductive Risk. California: University of California Press, Pg 134. 4. American Society for Reproductive Medicine, (2012). Age and Fertility. [online] Available at:
publications/bookletsfact-sheets/english-fact-sheets-and-info-booklets/Age_and_Fertility.pdf [Accessed 04/02/20]. 
3. Healthline, (2017). Estradiol Test. [online] Available at: [Accessed 04/02/20]. 6. Colorado Women's Health, (2020). Test for Ovarian Reserve. [online] Available at: [Accessed 04/02/20].