One of the silver linings of pregnancy is avoiding your period. Of course, pregnancy comes with its own set of concerns. Stretch marks? Check! Cravings? Check! Plus that whole getting a human out of your body thing. After birth, you’ll bleed for a few weeks as the uterus shrinks to pre-pregnancy size. But what happens after that?

Most people want to know two things about menstruation post-baby: when is my period coming back, and what is it going to be like? To answer these questions, we consulted Randee Masciola, a women’s health nurse practitioner, doctor of nursing practice, and professor at The Ohio State University College of Nursing.

The short answer to both? It depends. When your period comes back after giving birth is often highly dependent on one thing: whether or not you’re breastfeeding. According to Dr. Masciola, “If you’re not breastfeeding, most women (about 80 percent) will get their menses eight to 10 weeks after delivery. Some can be as early as 28 days.”

But some women who are breastfeeding can expect to go longer without a period, especially if they’re exclusively breastfeeding (meaning they’re not supplementing their baby’s diet with any formula, donor breast milk, or food). Most women who are exclusively breastfeeding can expect to be period-free for at least six months. But everyone’s different — some breastfeeding moms will return to menstruation quickly, while others can wait up to a year or longer.

Your lack of period while breastfeeding is actually due to temporary form of infertility called lactational amenorrhea (amenorrhea means “the absence of menstruation”), Masciola says. The frequent nursing of a baby signals to the body that there aren’t enough bodily resources to get pregnant again, thus delaying the return of fertility. In fact, exclusively breastfeeding can be “up to 98 percent effective as contraception the first six months,” says Masciola. But it’s only effective for those six months, and if you restart menstruationat any time, the LAM method must be supplemented with another form of contraception.

When your period finally does make its return, it may look and feel unfamiliar. Periods after birth are often quite different than the periods you had before you conceived, Masciola says. “For about a third of women, menses stay the same, about a third have heavier and crampier menses, and about a third have milder cramps and bleeding.”

It’s also not uncommon for that first postpartum period to be quite heavy, with more pain and cramping than you were used to. You don’t have to suffer in silence, says Masciola: “If you’re bleeding [through] more than a pad an hour, you need medical attention. The same is true if the pain is rated seven out of ten and not managed with over-the-counter medication.” If you continue having very painful or heavy periods for several months, that’s also worth a visit to your doctor, midwife, or nurse practitioner.

Postpartum periods can also often take awhile to become regular again, as your hormones self-regulate over time. You might have very long or very short cycles, or go a few months without having a period at all. Postpartum thyroiditis, a thyroid condition that affects about five to ten percent of women, can also interfere with your menstrual cycle.

Remember, too, that you might need to change your regular menstrual products after birth. You may find that certain tampons are irritating or that you need to invest in some heavy-duty pads. If you’re a menstrual cup user, you may have to switch sizes of cup (most menstrual cup manufacturers have two sizes: one for people who have not given birth and one for people who have). This is true even if you birthed by cesarean.

Lastly, if your period doesn’t return in a few months after giving birth, and you didn’t breastfeed or have since stopped, it’s worth checking in with your healthcare provider. Hormonal testing and other troubleshooting can help diagnose any potential issues, especially if you want to get pregnant again.

Carrie Murphy is a freelance writer and doula in Albuquerque, NM. Read more on her website, carrie-murphy.com.