Libido is a person's sexual desire or interest in sex. It varies widely between people and changes naturally over time, and hormones, stress, health and relationships can all affect it.
Low libido has many possible causes. Common ones include stress, anxiety or depression, relationship problems, tiredness, and sexual problems such as vaginal dryness or pain. Some medicines, including certain antidepressants and hormonal contraception, can also lower sex drive.
Hormone levels shift during the menstrual cycle, pregnancy, after birth and around menopause. Falling estrogen and testosterone in midlife can reduce desire for some people and cause vaginal dryness. Looking after a new baby is also tiring, so a lower sex drive after birth is common.
A change in libido is only a problem if it worries you or your partner. A GP is a good first contact if you are concerned, if you think a medicine or contraception may be affecting it, or if your sex drive does not return after pregnancy. Treatment depends on the cause and may include counseling, a change of medicine or treatment for menopause symptoms.
Changes in sexual desire are very common and are not a sign that something is wrong in every case. Life events, sleep and general health all play a part. Talking openly with a partner and a health professional can help when the change feels distressing.
Sources: NHS, MedlinePlus.