Frequent and effective sucking of the baby is responsible for the suppression of the ovarian cycle. When a mother
is "fully" or nearly fully breastfeeding and remains amenorrheic (without monthly periods), breastfeeding is more than 98
percent protection from pregnancy in the first six months.
If there is any vaginal bleeding (after the 56th day postpartum)
and in the first six months AND the mother is fully or nearly fully BF, it is likely that ovulation did not occur. But, this
is a warning sign that fertility (ovulation) is about to begin again. After six months, it becomes increasingly likely that
ovulation will occur BEFORE the first period.
The return of menstrual periods depends on the mother's response to
the hormonal levels affected by breastfeeding. "Mothers who nurse their babies unrestrictedly (for comfort as well as for
feeding, night as well as day) generally go without menstrual periods for many months... Shiela Kippley reports on a survey
of women who practiced total, unrestricted breastfeeding. They averaged 14.6 months without resumption of menstrual periods
The key is frequent nursing. When a baby has bottles of supplemental formula or juice, pacifiers,
starts solid foods, sleeps longer stretches at night the frequency of nursing at the breast is decreased. "One study found
that going six hours or more between feedings and nursing fewer than five times a day with a total sucking duration of less
than sixty-five minutes were associated with the return of fertility."
"Some mothers who nurse their babies without
supplements nevertheless resume their periods at six months portpartum. Other mothers whose babies sleep through the night
or who give their babies a pacifier for extra sucking do not resume having periods until close to the baby's first birthday.
Individual hormonal differences can either lengthen or shorten the period of natural infertility."
(Quotes above from
The Breastfeeding Answer Book by Nancy Mohrbacher and Julie Stock.)
I hope this helps to clarify things for you. Write
again if you sill have questions.
Barbara Berges BS, RN, IBCLC