Can You Get Pregnant While Breastfeeding?

Q: Can you get pregnant while breastfeeding?

A: Breastfeeding can lower your chances of getting pregnant by delaying ovulation. However, it is still possible to get pregnant. Research studies have indicated that under perfect conditions, the pregnancy rate for someone who is breastfeeding is 2% or lower.

Get Pregnant During Breastfeeding?

When a woman is breastfeeding her baby, the sucking signals to the pituitary gland to produce a hormone called prolactin (also known as luteotropic hormone or luteotropin). The purpose of prolactin is to stimulate the production of milk. An elevated level of prolactin can suppress the production of follicle-stimulating hormone (FSH), which is the main hormone involved in stimulating the ovaries to produce mature eggs. A low level of FSH means that there is a lower likelihood that a mature egg is produced. Without a mature egg, pregnancy cannot take place.

In fact, the process described above means that breastfeeding is sometimes used as a contraception method for couples who do not want another child soon. To be effective as a contraception method, the following criteria need to be met:

Your period has not returned.
Your baby is younger than six months.
The only food your baby is taking in is your milk through breastfeeding, and you do not go through long periods between feedings.

The last condition means that there should be no more than approximately four hours between feedings during the day, and six hours between feedings during the night—yes, this is saying that your baby should not be sleeping through the night. This can be a tough choice for parents, because every parent understands the value of having a baby who sleeps through the night, as it means more precious rest for them.

A research study by Labbok et al (1997)¹ showed that women who correctly adhered to the three criteria listed above had a pregnancy rate of between 1.5% to 2% over a 6-month period. Even for women who breastfed but did not adhere to all three criteria showed a pregnancy rate that was lower than that of the general public. This means that breastfeeding can indeed be linked to lower pregnancy rate, although it does not completely eliminate the possibility of pregnancy. Therefore, if you do not wish to become pregnant, using breastfeeding alone will not be enough.

[1] M. H. Labbok, V. Hight-Laukaran, A. Peterson, V. Fletcher, H. von Hertzen, P. F. A. Van Look, Multicenter study of the Lactational Amenorrhea Method (LAM): I. Efficacy, duration, and implications for clinical application. Contraception, 55, 327-36 (1997).

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