Can I get pregnant while breastfeeding if I don't have a period?
Yes, you can get pregnant while breastfeeding. It's a common misconception that breastfeeding is a natural contraception. There are some medical reasons behind this idea: Prolactin, the milk let-down hormone, causes the other components of the menstrual cycle to be suspended, which is why periods are irregular or even nonexistent in breastfeeding women. Usually.
Usually? Yes, some women's bodies rise above breastfeeding and begin cycling normally. This usually means that they're ovulating normally, and these are the women who can get pregnant while breastfeeding.
If you're having normal periods while breastfeeding, beware, because you're probably having regular ovulations and can conceive. If your periods are erratic, then your ovulations are too, and pregnancy is less likely but still not impossible.
The American College of Obstetricians and Gynecologists recommends, that "if you don't want to become pregnant during this time, you should use birth control." Your healthcare provider should be able to recommend birth control that can be safe and effective for you while breastfeeding.