An imbalance in your hormones may be making it more difficult for you to conceive and can also increase the risk of a miscarriage.
Your monthly cycle is governed by the reproductive hormones, the main ones being oestrogen, progesterone, follicle-stimulating hormone (FSH) and luteinising hormone.
In a monthly cycle, lasting approximately 28 days, the first half, called the follicular phase, starts on the first day of your period and lasts for about 14 days. At the beginning of each menstrual cycle, oestrogen and progesterone levels are low and FSH is produced by the pituitary gland in the brain which controls the whole endocrine (hormone) system. This triggers ovulation by stimulating the ovaries to produce oestrogen and the lining of the womb starts to thicken as it prepares to receive a fertilised egg. Oestrogen levels continue to rise until the pituitary gland releases LH which triggers ovulation. The egg (ovum) is then released from a follicle in the ovary and passes down the fallopian tube.
After ovulation at around day 10–14, comes the second half of your menstrual cycle called the luteal phase. Here the ovaries produce progesterone which prevents further ovulation from taking place in that cycle. If fertilisation does not occur the lining of the womb breaks down and menstruation takes place about 14 days after ovulation. At the same time there is a dramatic and rapid fall in oestrogen and progesterone and with this drop in hormone levels, the cycle begins all over again.
If fertilisation occurs, however, the egg implants itself into the wall of the womb where it begins to develop. Fertilisation takes place in the fallopian tube and once this happens the empty follicle which releases the egg forms the corpus luteum which produces progesterone. This is an important hormone in fertility because it maintains the womb lining during the second half of the cycle in readiness for a fertilised egg. It is also responsible for maintaining pregnancy.
What this test measures:
- FSH (follicle stimulating hormone)
- LH (luteinising hormone)
- AMH – a measure of ovarian reserve (your egg store)
- TSH (thyroid stimulating hormone)
- Free T4
- T3 – your active thyroid hormone, which is not measured on the NHS.
Progesterone will also be added on to this test to be measured on approximately day 21 of your cycle. This hormone maintains a pregnancy until the placenta take over around the 12th week.
Who should take this test?
- Any woman who is finding it difficult to conceive or has had a miscarriage.
- There is a strong connection between fertility and thyroid function, so it is important to look at thyroid function too.
- We will organise for the lab to send you the test kit.
- The test requires a blood sample and we can let you know where this can be taken.
- Your nutritionist will let you know the best time of the month to do the test.
- The test results will be returned to your nutritionist. Test results will be interpreted by your nutritionist at the consultation and a protocol tailored accordingly.