"Should I check my AMH before we start trying?" It is one of the most common questions women in their thirties ask, and a fair one. The AMH blood test is easy to arrange and the result comes back quickly. What it means, though, is often misunderstood. This guide explains what AMH and the other fertility hormones measure, when testing tends to be useful, and where its limits are.
What is AMH?
Anti-Müllerian hormone (AMH) is produced by the small follicles growing in the ovaries each cycle. Because the number of those follicles reflects the eggs still available, AMH is used as a marker of ovarian reserve, the quantity of eggs remaining. LML describes the test, listed in the BPR catalogue as Antimullerian Hormone (AMH Plus), as a way to assess ovarian reserve and to help predict the response to fertility treatments such as IVF. LML also notes that reference ranges vary with age and reproductive stage.
A 2022 review in the Journal of Clinical Endocrinology & Metabolism sums it up clearly: AMH is a good marker of egg quantity, but it does not reflect egg health or the chance of conceiving (Cedars, 2022). Age remains the strongest factor in fertility treatment success.
AMH does not predict natural conception
This is the point most often lost. In a prospective study published in JAMA, 750 women aged 30 to 44 who had been trying to conceive for three months or less gave blood samples. After adjusting for age and other factors, women with low AMH did not have a significantly different chance of conceiving within 6 or 12 cycles than women with normal values (Steiner et al., 2017). The same was true for high FSH.
So a low AMH result does not mean you cannot get pregnant naturally, and a normal one does not mean you have plenty of time. What AMH can do is help a fertility specialist plan treatment, and some women use it as one piece of information when thinking about timing or egg freezing, ideally with a doctor's guidance.
Things that can lower AMH without reflecting reserve
- Hormonal contraception can lower AMH temporarily (Cedars, 2022).
- Higher body mass index is associated with lower AMH, without this reflecting ovarian response (Cedars, 2022).
- Conditions that suppress the pituitary hormones can also lower it.
High AMH, on the other hand, may be seen in polycystic ovary syndrome, as LML notes in its description of the test.
The Fertility Hormones Profile
AMH is only one part of the picture. The Fertility Hormones Profile in the BPR catalogue measures five hormones:
- Follicle stimulating hormone (FSH), from the pituitary gland, which drives follicle growth.
- Luteinising hormone (LH), which triggers ovulation.
- Oestradiol (E2), the main oestrogen made by the ovaries.
- Testosterone, relevant to cycle regularity and conditions such as PCOS.
- Prolactin, which at high levels can disturb ovulation and periods.
LML describes this profile as useful for looking at hormonal balance when periods are irregular or when there are questions about fertility, and for monitoring hormone treatments. It can be done on a finger-prick home sample as well as on a blood sample taken by a phlebotomist.
Timing matters
FSH changes across the menstrual cycle. LML points out that the test may need to be done on specific days of the cycle to give useful results, and that FSH rises naturally with age. If you have regular periods, ask the doctor who will read the results which day to test. A single FSH test on its own is also available in the catalogue as Follicle Stimulating Hormone (FSH).
