Why are Hormones Important? Why Test Them Before Pregnancy?

Hormone

Function

FSH (Follicle Stimulating Hormone)

Stimulates egg growth, regulates the menstrual cycle, and helps assess fertility. Abnormally high FSH may indicate ovarian decline or low egg reserve. Abnormally low FSH means the body is not stimulating ovulation.

LH (Luteinizing Hormone)

The hormone that triggers ovulation. After ovulation, it causes Progesterone to be secreted to prepare the uterine lining for embryo implantation. Helps regulate the menstrual cycle. Imbalanced LH levels can prevent ovulation and make conception difficult. It normally works together with FSH.

Estradiol (E2)

Helps trigger ovulation, stimulates the growth of the endometrium, helps the uterine lining thicken, and ensures sufficient blood supply to support embryo implantation. It is an important indicator of ovarian function and the body’s readiness for pregnancy. Beyond conception, E2 also affects mood, sleep, libido, and metabolism.

Progesterone

The main hormone post-ovulation. It thickens the uterine lining, providing glands, blood, and nutrients for the embryo. It inhibits uterine contractions to prevent the embryo from dislodging or being expelled. It also prepares the breasts for lactation after delivery.

Prolactin

Controls the balance of female sex hormones. If Prolactin is too high, it can cause missed or irregular periods, making it difficult to conceive.

TSH / FT4

Controls thyroid gland function. Imbalanced thyroid hormones can cause anovulation or irregular periods, make embryo implantation difficult, and may increase the risk of miscarriage.

AMH (Anti-Müllerian Hormone)

An indicator of the quantity of eggs remaining in the ovaries (not egg quality). Used as a guideline for infertility treatment, and for detecting premature ovarian insufficiency (POI) or PCOS.