Knowing your menstrual cycle — Special circumstances

After pregnancy or breastfeeding – After pregnancy, a woman’s body produces high levels of prolactin – a hormone that helps to produce breast milk. Prolactin also keeps oestrogen levels low which results in a woman’s menstrual cycle being put on hold. It generally takes about four weeks for a woman’s cycle to return after giving birth, but if she breastfeeds, it may be considerably longer.

Note: After pregnancy, about 50% of women ovulate before their periods return. This means they may be fertile again before they know it.

The cervix takes about 12 weeks to heal after childbirth and won’t feel the same as it did before pregnancy. Your cervix may feel harder and it probably won’t close as fully as it did before birth. Cervical changes will still occur, however, and can be used in monitoring your cycle after pregnancy.

Basal body temperature may also be disrupted following pregnancy, particularly if you are breastfeeding. At first there may be more changes in your temperature, and your readings may be lower than they were before pregnancy, but there will still be a distinct rise when you ovulate.

After stopping the Pill

The Pill works as a contraceptive by preventing ovulation. Once you stop taking the Pill, ovulation tends to return within a couple of weeks, but for some women it may take longer. Mucus and basal body temperatures may also be affected by leftover hormones from the Pill. This can make it difficult to follow your cycle for the first month or two after you stop using the Pill.

Other hormonal contraceptives

Hormonal injections, patches and implants can affect a woman’s cycle even after she stops using them. In some cases it may take many months for a woman’s cycle (and fertility) to return.

PCOS

Menstrual cycles of women with Polycystic Ovarian Syndrome (PCOS) are likely to be irregular, very long (more than 35 days) and often anovulatory.