How Pregnancy Whilst Breastfeeding Affects Your Fertility

It can take weeks, months, or longer for women to become fertile again after having a baby. After vaginal childbirth, it takes an average of six weeks for the body to heal. If you don’t breastfeed, your period may return around the same time.

Once a period returns, women are considered fertile and are able to conceive their next baby. However, breastfeeding can delay the return of your menstrual cycle and therefore, the ability to get pregnant again for a while.

Whether you’re considering having a baby as soon as possible, or you’re going to wait, it’s important to learn about how breastfeeding can affect your fertility.

 

Can you get pregnant while breastfeeding?

Although it’s possible to become pregnant again while breastfeeding, mums who breastfeed exclusively (or almost exclusively) tend to experience a delay in the return of their fertility. This is known as lactational amenorrhoea.

In fact, exclusive breastfeeding may even be used as a natural form of birth control, known as the Lactational Amenorrhoea Method (LAM). Exclusive breastfeeding is 98-99.5% effective in preventing pregnancy, as long as the following criteria are met: 

  • You gave birth less than six months ago
  • Your menstrual periods have not yet returned
  • You breastfeed exclusively (not supplementing with formula)

When breastfeeding exclusively - which means nursing at least every four hours in the day and every six hours at nighttime - the body naturally stops ovulating. And you can’t get pregnant if you don’t ovulate.

No ovulation means no period either. Hence the term “Lactational Amenorrhoea Method.” “Lactational” refers to breastfeeding, and “amenorrhoea” means not having your period.

 



How soon can you get pregnant after having a baby?

It’s possible to become pregnant again before having your postpartum period. This can occur as early as four weeks or as late as 24 weeks (or later) after giving birth, depending on if you’re breastfeeding exclusively or not. Your chances of getting pregnant again may increase when your baby is six months old. This is when babies start to take food and drink other than breast milk.

Breastfeeding and the hormones that go along with milk production can prevent ovulation from returning. Most nursing mums won’t start menstruating again for the first three to six months. Many others only get their first period at nine months or more after giving birth. However, some can conceive sooner, while others start ovulating later.

Ultimately, the time it takes for a woman’s period to return after giving birth varies greatly. Every woman's body is different, and the timetable for first postpartum ovulation is unpredictable. But once you start menstruating again, it’s usually a sign that your fertility has returned, or will return soon.

 

Ways to maximize your natural period of fertility

Try changing your breastfeeding pattern to bring your period back sooner. Although there is no general rule of breastfeeding intensity which predicts the return of fertility, abrupt changes are known to bring fertility back quicker. Breastfeeding less often, like only in the morning and at bedtime, may be enough to bring back your period.

Other factors that could affect the return of fertility:

  • One study found that mama’s who were separated from their babies (but expressed 100% breastmilk) had a 5.2% higher chance of pregnancy during the first six months (Valdes 2000)
  • In some populations, night nursing has been shown to slow the return of fertility
  • Introducing solid foods can affect fertility. As the baby gradually starts to eat more solids and takes less milk from your breasts, fertility is more likely to return.

All that said, there is no magic formula to make fertility return. Some women get pregnant while breastfeeding, so weaning may not even be necessary. Once your periods have come back and settled into a regular pattern, it’s likely that breastfeeding is no longer affecting your fertility.

 

Is it safe to breastfeed while pregnant?

It is generally considered perfectly safe to breastfeed while pregnant. Your body will continue to produce enough milk to nourish your infant, while your unborn baby will get all the nutrients they need from your body.

However, breastfeeding does cause mild contractions due to the release of small amounts of oxytocin. While safe in uncomplicated pregnancies, this could cause preterm labour in rare cases. Therefore, it’s important to talk to a healthcare provider if you become pregnant while breastfeeding. Generally, doctors will advise weaning your child in the following circumstances:

  • If your pregnancy is considered high risk or you’re at risk for miscarriage
  • If you’re carrying twins or multiples
  • If you have been experiencing bleeding or uterine pain
  • If you’ve been advised to avoid sex while pregnant

It’s important to note that most doctors advise waiting at least 18 months between giving birth and getting pregnant again. This will give your body enough time to make a full recovery from your last pregnancy before it’s ready for the next one. Getting pregnant again before the 18 months may increase the risk of complications in the pregnancy.

 

References:

Natural Child Spacing and Breastfeeding by Jen O’Quinn

https://pubmed.ncbi.nlm.nih.gov/11172791/ by Valdes

https://www.whattoexpect.com/getting-pregnant/ovulation/can-you-get-pregnant-while-breastfeeding/ - What to expect