Breast-feeding is known to delay your period. This can come as a welcome perk for mothers who wish to delay menstruation even longer than nine months. While some women don’t get periods at all during the months they nurse, some get them irregularly. In a sense, this can be even more frustrating than planned cycles.

Are you wondering why periods seem to stop while breast-feeding? Read on to learn why hormone changes are to blame.

When your baby is born, you’re already equipped with natural nutrients needed for feedings. Unless you can’t breast-feed, your doctor will likely encourage you to do so. This is often regarded as the safest, healthiest form of nutrition for newborns.

While it might seem like breast milk simply appears when your baby is born, there is much more at play here. In fact, just as hormones helped support your pregnancy, they are also responsible for breast-feeding. Prolactinis the primary hormone responsible for breast milk production. It’s produced by the pituitary gland, which is located in the brain.

Prolactin also prevents menstruation. Breast-feeding keeps these hormone levels high, so the longer you nurse, the more likely you will experience a light period, or no period at all. On the flip side, as you wean your baby off of breast milk, your periods will likely return relatively quickly.

Your baby will drink the most breast milk during the first few months of their life. As your baby needs less milk, and also starts eating solid foods, the pituitary gland will sense this feeding change and produce less prolactin. As prolactin levels slow down, you might find that your cycle returns, despite the fact that you’re technically still breast-feeding.

If you do get your period while breast-feeding, you might notice other unexpected changes too. You might find, for instance, that your baby isn’t as interested in feeding times, and will actually eat less during your period. This is thought to be related to taste changes in the milk.

Or, the situation can be the opposite. Since prolactin controls milk production, you might not offer as much of a supply during your period. Then your baby might want to feed more frequently.

There is no specific set timeline for a return of normal cycles since every woman is different. Chances are that if you were pretty regular before pregnancy, then your periods should return and normalize quickly after you stop breast-feeding.

According to Dr. Karen Leham, M.D., the timeframe for normalizing periods is anywhere from six months to two years.

It’s also important to note that a lack of a period doesn’t necessarily mean a lack of ovulation. Some women assume that they can’t get pregnant while breast-feeding if they aren’t menstruating regularly. This is also a top contributor of surprise pregnancies in nursing mothers.

While not entirely impossible, pregnancy can be difficult while breast-feeding. Keep in mind that prolactin is responsible for both milk production andpregnancy support. It can be difficult for the body to support both at the same time. If you want to get pregnant at this time, talk to your doctor about your options.

An irregular cycle really means that your cycle is either shorter or longer than the typical 28 days. If you’re breast-feeding, chances are that irregular periods are related.

However, there are many other things that can affect a regular menstrual cycle, even when you’re nursing. Before you assume that breast-feeding is the cause of delayed or sporadic periods, you’ll want to consider other symptoms, like spotting, heavier than normal bleeding, or lengthy cycles.

Consider discussing irregular menstruation with your doctor, even if you’re breast-feeding. They will want to rule out other causes, such as:

  • uterine fibroids (noncancerous cells on the uterus)
  • extreme weight loss
  • ovarian cysts or polycystic ovary syndrome (PCOS)
  • pelvic inflammatory disease

You will definitely need to call a doctor right away if you experience any severe pain, or if you have heavy spotting between periods.

Though certain health conditions may cause irregular periods, hormonal changes are the most common cause when you’re breast-feeding. Once you start to ease up on breast-feeding, especially after the first year as your baby gains more nutrition from foods, your periods will start to normalize again.

If you don’t breast-feed, you should have normal cycles again right away. You might even get your next period four weeks after delivery. Call your doctor if you experience irregular periods despite the fact that you don’t breast-feed.