Can pregnancy occur during lactation (breastfeeding)?

From the Guidelines

Yes, you can get pregnant while breastfeeding, and the risk of pregnancy increases when the strict criteria for the lactational amenorrhea method (LAM) are not met. Breastfeeding can reduce fertility by suppressing ovulation, especially during the first six months after childbirth when your baby is exclusively breastfed (no formula or solid foods) and feeds frequently, including at night 1. This natural birth control method, called LAM, is about 98% effective when all conditions are met, including amenorrhea, fully or nearly fully breastfeeding, and less than 6 months postpartum 1. However, many women don't meet these strict criteria, and ovulation can return before your first postpartum period, meaning you could become pregnant without realizing you're fertile again.

Key Points to Consider

• Once your baby starts sleeping longer at night, begins eating solid foods, or reaches six months of age, the contraceptive effect significantly decreases 1.
• If you want to avoid pregnancy, it's recommended to use additional contraception methods even while breastfeeding.
• Options compatible with breastfeeding include:
  • Barrier methods (condoms, diaphragms)
  • Hormonal methods like progestin-only pills (such as Micronor or Nor-QD)
  • IUDs
  • Natural family planning

Important Considerations

• Combined hormonal contraceptives containing estrogen are typically not recommended during early breastfeeding as they may reduce milk supply.
• The likelihood of ovulation is low from days 1–7 of the menstrual cycle, and after a spontaneous or an induced abortion, ovulation can occur within 2–3 weeks 1.
• A recent systematic review reported that the mean day of first ovulation among postpartum nonlactating women occurred 45–94 days after delivery, and among women who are within 6 months postpartum, are fully or nearly fully breastfeeding, and are amenorrheic, the risk for pregnancy is <2% 1. To minimize the risk of unplanned pregnancy, it is essential to use a reliable contraceptive method in addition to breastfeeding, and women should be advised to use another contraceptive method to use until the health-care provider is reasonably certain that she is not pregnant and can insert the IUD 1.

From the Research

Can Pregnancy Occur While Breastfeeding

• Pregnancy can occur while breastfeeding, as breastfeeding is not a foolproof method of contraception 2, 3, 4, 5
• The lactational amenorrhea method (LAM) can be an effective form of contraception, but it requires specific conditions to be met, including exclusive or quasi-exclusive breastfeeding on demand, day and night, and the baby being under 6 months old 2
• Studies have shown that breastfeeding alone is not an effective form of contraception, as all women in one study resumed normal ovulation while still breastfeeding 3
• The effectiveness of LAM as a contraceptive method decreases over time, with a cumulative probability of conception increasing after 6 months of amenorrhea 3
• Factors that influence the return of fertility while breastfeeding include the frequency and duration of breastfeeding, with more frequent and longer episodes of breastfeeding associated with a longer period of anovulation and infertility 4, 5

Factors Influencing Fertility While Breastfeeding

• The frequency and duration of breastfeeding are critical factors in determining the return of fertility, with a significant decrease in suckling frequency and duration observed prior to the resumption of ovulation and conception 4
• Maternal age and parity can also influence the length of postpartum amenorrhea and infertility 5
• The introduction of supplements into the baby's diet does not affect the effectiveness of LAM as a contraceptive method in the first 6 months of breastfeeding 3

Awareness and Understanding of LAM

• Many women are unaware of the effects of breastfeeding on menses and fertility, and may not understand the conditions required for LAM to be an effective form of contraception 6
• Clinicians providing counseling about postpartum contraceptive options should include more information on LAM to increase awareness and understanding among women 6