Menstrual cycles cease during pregnancy. After a woman gives birth, menstrual cycles may not occur at the same interval or last the same amount of time as they did before pregnancy. Some women also experience a change in menstrual flow, with periods becoming lighter or heavier. The time it takes for menses to start after giving birth also varies. In some women, delayed postpartum bleeding may be mistaken for an abnormal period.
Bleeding occurs for up to six weeks after birth, as the uterus returns to normal size and the thicker than normal uterine lining sheds. Postpartum bleeding starts out bright red for the first several days and then turns pinkish or brownish for the next week. After two weeks, bleeding turns to a light cream-colored or yellowish discharge for the next five weeks. This is not menstrual bleeding. Women who don't breastfeed normally resume menstruating within seven to nine weeks, while breastfeeding women may not have a period for up to six months, Nursing instructor Nan Anderson of Calhoun Community College states.
Hormonal imbalances often occur in the first few months after childbirth. Periods may be irregular and heavier than normal for the first three to four months after delivery. Ovulation, release of an egg from the ovary that can lead to another pregnancy, can occur as soon as 27 days after delivery and usually occurs within the first two months in non-breastfeeding women, so another pregnancy could cause an absence of menstruation even a month or two after delivery. Breastfeeding suppresses ovulation and menstruation for up to six months. Delayed postpartum hemorrhage, which occurs in about 1 percent of women, according to Babycenter, can occur up to 12 weeks after delivery and could be mistaken for an abnormal period.
Abnormally light, heavy, short or otherwise different than normal periods are the rule rather than the exception for the first few months after giving birth. If abnormal periods persist for more than three or four months, or if menses don't resume within several months after giving birth in a non-breastfeeding woman, a visit to a medical practitioner may be in order, the National Health Service advises.
Pregnancy and childbirth cause a number of hormonal changes. It takes time for the body to get back to normal. However, treatments to regulate hormone levels, such as birth control pills, may help get things back to normal in non-breastfeeding women. Women who are breastfeeding should not take oral contraceptives, the NHS warns. If delayed postpartum hemorrhage occurs, treatment of the cause stops abnormal bleeding.
While irregular, absent or otherwise abnormal periods in the first few months after delivery may be annoying, they're rarely harmful in any way. However, if clots or very heavy bleeding occurs suddenly a few weeks after delivery, part of the placenta or uterine lining may not have passed normally, or uterine infection could be present. Passing clots or bleeding that saturates one sanitary pad an hour merits prompt investigation, Breastfeeding.com warns.