Hormones are chemical substances, produced by specialized glands in the body that alter and control the activity of specific organs. Some hormones have particular actions and sometimes they also monitor the actions of other hormones. Fertility is under minute control of various hormones and the actions, levels, and interactions of these decide how difficult or easy it may be for a person to achieve pregnancy.
In women, the menstrual cycle of around 28 days is under hormonal control. The growth and release of eggs from the ovaries i.e. ovulation and preparation of the lining of the womb for the fertilized egg to implant are allmonitored by the hormones. The lining of the womb sheds resulting in menstruation when a pregnancy does not occur.
Hormones that control this process are –
- Follicle stimulating hormone (FSH) –It controls the growth and maturation of an egg in the ovary. As the no. of eggs are at the verge of finishing, the FSH levels start rising. A patient with a poor ovarian reserve will have high FSH levels resulting in poor response to ovarian stimulation.
- 2.Luteinising hormone (LH) – It causes the release of an egg once it is matured and stimulates the production of testosterone by the testes in men. LH level varies depending on the time of the cycle and can help in monitoring the IVF cycle.
- Oestrogen – It helps in thickening and preparing the lining of the womb for implantation of the embryo in both IVF as well as natural pregnancy. It increases the flow of the blood to the uterus. It also prepares the breasts for milk production.
- Progesterone –When it implants, it supports and maintains the lining of the womb and the pregnancy. Ovarian stimulation protocols affect the progesterone balance.Hence, all IVF cyclesduring the implantation and early pregnancy are supported with progesterone supplementation. Progesterone relaxes the uterine muscle and modulates the immune response, thus favouring the embryo implantation and early growth. It is an extremely vital medication for pregnancy support.
Any imbalance in the above-mentioned hormones hampers the chances of a healthy pregnancy. Fertility treatments aim at optimising and regulating the effects of these hormones. Several factors control the success of fertility treatments and reproductive hormones are one of the chief aspects.
Other hormones that mark the success of treatments are: –
- Anti-Mullerian hormone (AMH) – Produced by the ovarian follicles, it is a marker for ovarian reserve and can help in predicting the response to fertility medications. When the ovaries are within the normal range, they respond more effectively and more eggs are retrieved thusincreasing the chances of success. When AMH is low, it indicates poor ovarian reserve. For e.g. in the case of premature ovarian ageing, both the quality and quantity of eggs obtained after stimulation is poor. Women with higher AMH have the risk of Ovarian Hyperstimulation Syndrome.
- Serum Prolactin is produced by the pituitary gland. High levels of this hormone may interfere with the growth of follicles and the uterine lining resulting in reduced fertility and increased risk of miscarriages. If a high level of this hormone is detected, they are generally treated before embarking on IVF treatments.
- TSH (Thyroid Stimulating Hormone) – Thyroid hormones are a vital regulator of all metabolic activities of the body. They fine-tune ovarian and uterine functions throughtheir interactions with other fertility hormones. TSH is a marker of thyroid activity. Irregular functioning of the thyroid gland increases the risk of infertility, miscarriage, premature births, ovarian cysts, mental and developmental disorders in the baby.
All the above-mentioned hormones are checked during routine fertility workup.