Fertility Knowledge Centre
Clear answers, honest about the evidence
22 topics
- ConditionsClinical review pending
Polycystic ovary syndrome (PCOS)
A common hormonal condition that can affect ovulation, periods, skin and hair, and long-term metabolic health.
- ConditionsClinical review pending
Insulin resistance
When the body needs more insulin than usual to keep blood sugar in range, a common feature of PCOS.
- Hormones & blood testsClinical review pending
Oestrogen (oestradiol)
The main hormone produced by developing follicles, preparing the womb lining for a possible pregnancy.
- Hormones & blood testsClinical review pending
Progesterone
Produced after ovulation; a blood test about a week before your period can confirm that ovulation has happened.
- Hormones & blood testsClinical review pending
Prolactin
A pituitary hormone; raised levels can interfere with ovulation and periods.
- Hormones & blood testsClinical review pending
Thyroid function
Both underactive and overactive thyroid can affect cycles, fertility and pregnancy.
- Hormones & blood testsClinical review pending
Sex hormone-binding globulin (SHBG)
A protein that carries testosterone in the blood and helps determine how much is active.
- Hormones & blood testsClinical review pending
Androgens (including testosterone)
Hormones such as testosterone, present in all women, that can cause symptoms when raised.
- Hormones & blood testsClinical review pending
Anti-Müllerian hormone (AMH)
Reflects the number of eggs remaining (ovarian reserve). It is not a fertility test on its own.
- Hormones & blood testsClinical review pending
Follicle-stimulating hormone (FSH)
A pituitary hormone that stimulates follicles to grow. It is usually measured early in the cycle.
- Hormones & blood testsClinical review pending
Luteinising hormone (LH)
The hormone whose surge triggers ovulation, and the basis of ovulation predictor kits.
- Womb & liningClinical review pending
Endometrial thickness
The thickness of the womb lining on ultrasound, which changes throughout the cycle.
- Cycle & ovulationClinical review pending
Ovulation
The release of an egg from the ovary, and the signs that can help you recognise it.
- Cycle & ovulationClinical review pending
The luteal phase
The second half of the cycle, from ovulation to your next period.
- ConditionsClinical review pending
Endometriosis
Tissue similar to the womb lining grows outside the womb, causing pain and sometimes fertility problems.
- Womb & liningClinical review pending
Adenomyosis
Tissue like the womb lining grows into the muscle wall of the womb.
- Womb & liningClinical review pending
Endometrial polyps
Overgrowths of the womb lining, often harmless, sometimes causing irregular bleeding.
- Womb & liningClinical review pending
Chronic endometritis
Persistent, low-grade inflammation of the womb lining. An area of active research.
- PregnancyClinical review pending
Recurrent miscarriage
Experiencing two or more pregnancy losses, and the investigations and support available.
- Life stagesClinical review pending
Perimenopause
The years of hormonal transition before the final menstrual period.
- ConditionsClinical review pending
Premenstrual dysphoric disorder (PMDD)
A severe form of premenstrual symptoms with significant mood changes in the days before a period.
- InvestigationsClinical review pending
Fertility investigations
What tests are usually offered, and when, if you are having difficulty conceiving.