Women who notice anything unusual about their periods, such as shorter or longer cycles or heavier periods, should meet with their provider to discuss options. (For Health Beat)

After delivering a child, many new mothers expect to get their pre-baby rhythm back soon—at least as far as their period goes.

Turns out there’s a wide range of what’s normal for new moms and menstruation, making a time of topsy-turvy adjustment even more unpredictable.

Women who aren’t breastfeeding typically get their periods back around six weeks after delivery—some at three weeks and others eight weeks, said Megan Warner, a family nurse practitioner at Corewell Health.

Women who breastfeed may wait longer. It’s typical to not have a period until they’ve weaned, which could be as long as two years. This means sexually active women must be cautious during this time.

“You ovulate before your period returns, which means you can get pregnant even before you have a post-pregnancy period,” she said.

That first period is different from the bleeding experienced in the weeks after birth. That’s known as lochia and it’s the way the body breaks down all the material that’s no longer needed.

It often contains bright red blood, especially in the first few days. It also contains mucus, uterine tissue and other materials.

“Most women will have typical postpartum bleeding anywhere from two to six weeks after birth,” Warner said.

That can depend on whether they gave birth vaginally or via cesarean section, which typically leads to less bleeding.

That’s all normal as the uterus resumes its pre-pregnancy shape, Warner said. The uterus is approximately 3 inches long before pregnancy, but it stretches to about 15 inches by the time the baby is born.

“So it takes time to shed that material, to go back down to its normal pre-pregnancy size.”

Breastfeeding

Just as pregnancy signals complex hormonal changes, so does the postpartum transition.

“Breastfeeding causes an increase in prolactin, which drives your estrogen down,” Warner said. “That tells your body not to ovulate, so there won’t be a period in most cases.”

There’s a common belief that breastfeeding provides natural birth control. And to a degree, that’s true—but it’s not foolproof, Warner said.

Many women may not breastfeed exclusively, sometimes supplementing with formula. And they may ovulate while breastfeeding.

Even women who pump breast milk lose some of that natural birth control effectiveness in the first six months.

After a baby is 6 months old, breastfeeding-as-birth-control becomes far less effective.

For women who are not breastfeeding and haven’t gotten a period within three or four months, Warner recommends a pregnancy test.

Once pregnancy has been ruled out, the absence of periods for longer than three to four months in non-breastfeeding women could mean something more is going on, Warner said.

In some cases, there might be thyroid issues, she said.

Similarly, women can experience amenorrhea, the absence of periods, after they stop breastfeeding.

“It can take a little while for those prolactin levels to decrease and estrogen levels (to) ramp back up,” she said. “It’s not unusual for it to take three or four months for periods to resume.”

Rethinking birth control

Much of this is discussed at a woman’s postpartum checkup at the six-week mark, where a care provider will also discuss physical recovery after birth, sleep, fatigue, sexuality and emotional well-being.

Up to 40% of women don’t make time for this important appointment, Warner said.

Birth spacing and birth control are also covered. Often, new moms are so busy, tired or overwhelmed with caring for a new baby that getting pregnant again is the last thing on their minds.

But up to 30% of women may get pregnant again within 18 months of giving birth.

“You’re going to ovulate before you’re going to have your period. And you won’t know you’re ovulating,” Warner said. “So if you’re having unprotected intercourse in that timeframe, there’s a chance for an unexpected pregnancy.”

When a new mom is not breastfeeding but she’s sexually active, it’s recommended that her partner use a condom during intercourse—at least until the mom’s checkup at the six-week point, Warner said.

That’s an ideal time to make decisions about birth control.

Research suggests that it’s best for a woman to wait at least 18 months before having her next child.

Women who don’t want to become pregnant in the near future may choose to get an intrauterine device at the six-week checkup, Warner said.

But there are many reliable forms of birth control, and providers can help each woman choose one that’s best for her needs.

Within months of giving birth, most women’s periods return to their pre-pregnancy style, Warner said.

“If you’ve had cramps before, you’ll likely have cramps again,” she said.

It’s important for women to take note of anything that seems unusual, such as increasingly irregular periods, shorter or longer cycles or heavier periods.

“Ask your provider,” Warner said. “It’s normal to have questions. Your body is going through lots of changes. We can help you figure it out.”