**Contraception:**
Hormonal contraceptives, such as the combined pill, contain oestrogen and progesterone. High levels of oestrogen inhibit the production of FSH (Follicle-Stimulating Hormone) by the pituitary gland. This prevents an egg from maturing in the ovary. Progesterone also helps by causing the cervical mucus to thicken, making it difficult for sperm to reach the egg, and by inhibiting ovulation.
**Treatment of Infertility:**
If a woman has low levels of FSH, her eggs may not mature. To treat this, she can be given fertility drugs that contain FSH and LH (Luteinising Hormone). These hormones stimulate the maturation of eggs in the ovary and trigger ovulation. This treatment can then be followed by IVF (In Vitro Fertilisation). In IVF, the mature eggs are collected, fertilised with sperm in a laboratory, and the resulting embryos are then implanted back into the woman's uterus to develop.
**Hormonal Contraception:**
The aim of hormonal contraception is to prevent pregnancy by disrupting the normal menstrual cycle. The most common form is the combined oral contraceptive pill, which contains synthetic versions of oestrogen and progesterone.
- **Oestrogen:** A consistently high level of oestrogen inhibits the pituitary gland from releasing FSH. Without FSH, no egg follicle will mature in the ovary.
- **Progesterone:** This hormone inhibits the release of LH from the pituitary gland, preventing ovulation (the release of a mature egg). It also causes the mucus in the cervix to become thick and sticky, forming a plug that makes it difficult for sperm to swim through to the uterus.
**Hormonal Treatment of Infertility:**
Some women are infertile because they do not produce enough FSH to stimulate their eggs to mature. This can be treated with fertility drugs.
- **FSH and LH Injections:** The woman is given injections of drugs containing FSH and LH. These hormones stimulate the ovaries to mature one or more egg follicles. This process is carefully monitored.
- **IVF (In Vitro Fertilisation):** This hormonal stimulation is a key first step in IVF. Once the eggs are mature, they are surgically collected from the ovary. They are then fertilised with sperm in a petri dish in a laboratory. The fertilised eggs develop into embryos. After a few days, one or two of the healthiest embryos are selected and transferred into the woman's uterus to continue development.
Expert