Infertility

Key facts

• Infertility is defined as the inability to conceive after 12 months of regular unprotected intercourse, or 6 months for women over 35, and affects roughly one in six couples globally.
• Many cases involve disrupted hormone signalling: polycystic ovary syndrome (PCOS), thyroid dysfunction, and luteal phase deficiency can prevent ovulation or stop a fertilised egg from implanting properly.
• Luteal phase deficiency means the body does not make enough progesterone after ovulation, and a progestogen such as dydrogesterone can support the uterine lining and early pregnancy.
• See a doctor after 12 months of trying, or sooner with irregular periods, pelvic infections, endometriosis, or previous miscarriages.

Hormonal causes and progesterone's role

Many cases of female infertility involve disrupted hormone signalling. Conditions such as polycystic ovary syndrome (PCOS), thyroid dysfunction, and luteal phase deficiency can prevent ovulation or stop a fertilised egg from implanting properly. Luteal phase deficiency, in particular, means the body does not produce enough progesterone after ovulation to prepare and sustain the uterine lining. Supplementing with a progestogen such as dydrogesterone is a common approach in assisted conception cycles and in supporting early pregnancy when progesterone levels are insufficient. It sits within the broader women's health treatment area.

Other contributing factors

Structural issues such as blocked fallopian tubes, endometriosis, and fibroids can also prevent conception, as can age-related decline in egg quality and quantity. Male factors, including low sperm count or motility, contribute to roughly half of all cases, so investigation typically covers both partners rather than assuming the cause lies with one.

When to seek further assessment

See a doctor if you have been trying to conceive for 12 months without success, or sooner if you have irregular periods, a history of pelvic infections, endometriosis, or previous miscarriages. Early investigation for both partners usually includes blood hormone tests, an ultrasound, and a semen analysis, allowing a treatment plan to be tailored to the specific cause.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.