Can I get pregnant while breastfeeding?

You’ve probably heard that breastfeeding makes a great contraceptive, and while it’s not untrue, it’s also not the full story. Here we answer all of your questions about getting pregnant while breastfeeding, whether you’re trying to prevent it or would like to start trying for another baby.

How reliable is breastfeeding as a contraceptive?

In the first 6 months, breastfeeding can be a 98% reliable form of contraception, only as long as your period hasn’t returned yet, and you are exclusively breastfeeding (no other milk or food). If these criteria are not met, then it’s no longer a reliable form of contraception, and you will need to start another kind of birth control if you’re not actively trying to get pregnant.

How does it work as a contraceptive?

Breastfeeding offers some protection against ovulation, but it is possible to ovulate before your first period and get pregnant. The way this works is that the increase in hormones responsible for milk production and the let-down reflex, oxytocin and prolactin, suppress the hormone that stimulates the ovary to release an egg each month.

Can I get pregnant if I’m breastfeeding after 6 months?

Depending on how often your baby or toddler breastfeeds, it may still have a contraceptive effect if your period hasn’t returned, but it is not guaranteed.

When will my period return?

Anywhere between 6 months (or earlier) and 2 years, depending on the frequency of feeds and your unique body chemistry. Ovulation can occur before the first period, so be aware of any signs of ovulation.

Will breastfeeding affect my fertility?

Even once you start menstruating again, breastfeeding can influence the hormones involved in fertility. Full fertility may not return straight away. Charting your cycles will help to learn more about your fertility and ovulation. Struggling to get pregnant may not have anything to do with breastfeeding, so speak to your doctor and/or lactation consultant before making any changes, such as increasing the time intervals between feeds or weaning.

Will I have to stop breastfeeding before starting IVF?

You may be asked to wean your baby before being accepted into an IVF program, so research your options before making any difficult decisions. Head to the ABA’s article Breastfeeding and IVF for more information.

Is it safe to continue breastfeeding if I’m pregnant?

According to the Australian Breastfeeding Association, ‘You may be concerned about the viability of the pregnancy if you continue to feed. In a normal, healthy pregnancy, with no previous history of miscarriage in the first 20 weeks or preterm labour after 20 weeks, there is no evidence to suggest breastfeeding is threatening to a pregnancy.¹ ² If you do miscarry, it is unlikely to be because you are breastfeeding.’

If you experience cramping during breastfeeding, the concern is that it can cause preterm labour or possibly early pregnancy loss, but this is very rare. While unlikely, if you do experience cramping, speak to your obstetrician or midwife.

For more information, read Tandem breastfeeding – pregnant or newborn


  1. Ishii H 2009, Does breastfeeding induce spontaneous abortion? J. Obstet. Gynaecol 45(5): 864-868.
  2. Moscone SR, Moore MJ 1993, Breastfeeding during pregnancy. J Hum Lact 9(2):83-88.
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