Fertility glossary

Anti-Müllerian hormone — a blood marker that gives an estimate of ovarian reserve. It does not predict fertility directly, but is widely used in fertility assessment.

Absence of ovulation in a cycle. A common cause of irregular or missing periods and a key target of ovulation-induction therapy.

Your temperature at rest. It rises slightly after ovulation due to progesterone, so tracking it can help confirm that ovulation has happened.

Vaginal discharge that changes across the cycle. Around ovulation it becomes clear, slippery and stretchy (like raw egg white), signalling the fertile window.

An oral ovulation-induction agent (a selective estrogen-receptor modulator) that stimulates FSH release to grow a follicle.

An oral progestogen used for luteal-phase support — it helps maintain the uterine lining after ovulation.

The lining of the uterus. It thickens under estrogen and matures under progesterone, and is where the embryo implants.

The main estrogen produced by the growing follicle. It drives the thickening of the endometrium and the LH surge that triggers ovulation.

The roughly six days each cycle (the five days before ovulation plus the day of ovulation) when intercourse can lead to conception. See the ovulation calculator.

The specialty concerned with the wellbeing of the fetus — including the scans and tests done during pregnancy.

Vitamin B9, recommended from before conception through the first trimester to support neural-tube development. Also called folate; L-methyl folate is the active form.

A fluid-filled sac in the ovary containing a maturing egg. One follicle typically becomes dominant each cycle and releases its egg at ovulation.

The first half of the cycle, from the first day of the period to ovulation. Estrogen rises as the follicle grows.

Follicle-stimulating hormone, released by the pituitary. It drives follicles to grow — the target of most oral ovulation-induction agents.

The fertility hormones FSH and LH. Injectable gonadotropin therapy is used when oral agents don't achieve ovulation.

Human chorionic gonadotropin — the "pregnancy hormone" detected by pregnancy tests, and used in some protocols to trigger ovulation.

The embedding of the embryo into the uterine lining, roughly 6–10 days after ovulation.

Reduced sensitivity of tissues to insulin. It is closely linked to PCOS — high insulin drives excess androgen production by the ovaries.

Luteinising hormone. A sharp mid-cycle "LH surge" triggers the release of the mature egg — the basis of ovulation predictor kits.

The second half of the cycle, from ovulation to the next period — reliably about 14 days in most women.

An aromatase inhibitor used for ovulation induction. It is now a common first-line oral agent in anovulatory infertility.

The permanent end of menstrual cycles, defined after 12 consecutive months without a period. The transition phase is called perimenopause.

A form of vitamin B12, used with folate in nerve-health and energy-support formulations.

An insulin-sensitising medicine widely used in PCOS to improve metabolic and hormonal balance.

A sugar-alcohol that supports FSH signalling in ovarian cells; a common partner to metformin in PCOS management.

The classic way to estimate a due date: 280 days (40 weeks) from the first day of the last menstrual period.

The embryonic structure that becomes the brain and spinal cord. It forms within the first weeks, before pregnancy is often known — why folate matters early.

The release of a mature egg from the ovary, usually about 14 days before the next period.

Treatment to stimulate the ovaries to ovulate, most often with oral agents like letrozole or clomiphene.

Polycystic ovary syndrome — a common hormonal condition involving irregular cycles, androgen excess and sometimes ovarian cysts. Diagnosed by a doctor using the Rotterdam criteria.

The hormone of the luteal phase. It matures the uterine lining and maintains early pregnancy.

The class of hormones with progesterone-like action, used for luteal support and hormone regulation.

The first felt fetal movements, usually between weeks 16 and 20 of pregnancy.

The diagnostic framework for PCOS: at least two of irregular ovulation, androgen excess, or polycystic ovaries on ultrasound.

A form of vitamin E with potent antioxidant activity, used in menopause-support and skin-health formulations.

One of three pregnancy phases: first (weeks 1–13), second (14–27) and third (28–40).