By Heng Wen Xiu, MPhil, IBCLC

Time of the month. Aunt Flo. Shark week. These are some of the colloquial terms used to describe menstruation. Many women have a love-hate relationship with our period. Some of us might have heard that breastfeeding women do not experience menstruation until we have completely stopped breastfeeding. This article looks at topics relating to fertility, menstruation and breastfeeding.

Generally, breastfeeding women experience the return of their menstrual cycle between 9 and 18 months. Note that this is what happens to the majority of breastfeeding women, but it is not the only normal period. Healthy breastfeeding women have also resumed menstruating as soon as the first couple of months postpartum, and as late as post-weaning.

Factors Influencing Resumption of Menstruation

Usually, the menstrual cycle resumes when there is a sudden drop in how frequently a baby latches, especially at night (e.g., when the baby sleeps through the night or increases the intake of solids). Similarly, when a breastfeeding woman expresses her milk more and latches her baby less (e.g., when a working mother returns to work after her maternity leave), she may experience the return of her period sooner. It is thought that when there is less latching at the breast, less oxytocin is released into the woman’s bloodstream. Given that oxytocin inhibits ovulation, when less oxytocin is released, the woman will have a higher chance of ovulating as part of her menstrual cycle. There is also research showing that the amount of time a baby spends latching at the mother’s breast matters more than the amount of milk removed from the mother’s breast. Therefore, for mothers with babies who comfort-latch more, they may have their periods resuming later.

On the mother’s end, based on evolutionary psychology research, it may be possible to “trick” the body into believing that the body is ready for another pregnancy. The idea is to ensure that the body has abundant energy, such as through cutting back on strenuous activities, eating balanced meals and consuming sufficient calories, so that the body feels capable of nourishing both an unborn child in the womb and a breastfeeding child outside of the womb.

Impact on Breast Milk Supply

Some women experience a drop in breast milk supply during or just before their menstruation. This is again due to underlying hormonal changes. In these instances, it is helpful to continue latching the baby on demand (which may mean more frequently than usual), or to pump more often to express the amount of milk that the baby needs. Some women have found it useful to take a calcium/magnesium supplement – do speak to your healthcare provider for more information.

Breastfeeding and Birth Control

You may have heard of the term, lactational amenorrhea. It refers to the temporary cessation of the menstrual cycle while breastfeeding. This happens because the hormones involved in lactation act against the activities of the hormones involved in ovulation and menstruation – think of it as nature’s way of protecting your body from another pregnancy while it is still nourishing a baby. Lactational amenorrhea can be an effective birth control option, when the breastfeeding baby is below six months and exclusively breastfeeding (i.e., not taking any other forms of liquids or solids), and the mother has not resumed menstruating.

Some women prefer to use birth control while breastfeeding. There are two main categories of birth control options: physical and hormonal. Physical options (e.g., condom, intra-uterine device) can be safely used by breastfeeding mothers. For hormonal options, it is useful to note that the recommended option is the progesterone-only contraceptive pill, as there is no impact on breast milk supply for most women. Other progesterone-only options are also possible, though these have a higher likelihood of impacting breast milk supply. Combination options contain oestrogen, which similarly have a higher likelihood of reducing a mother’s breast milk supply.

Breastfeeding While Pregnant
Some women conceive successfully while still breastfeeding. Generally, it is safe to continue breastfeeding throughout a low-risk pregnancy. It is best to speak to your doctor or consult a breastfeeding-knowledgeable doctor on the safety of breastfeeding through your pregnancy. For women who can continue breastfeeding and choose to do so, they may experience a sudden drop in their breast milk supply, and physical discomfort such as sore nipples – these are due to underlying hormonal changes. In some cases, the baby may choose to wean due to the drastic drop in breast milk supply.

Concluding Thoughts
Fundamentally, menstruation and fertility are underpinned by hormonal processes. Every woman is different, and the way each of our body respond to the internal hormonal changes is different. It is also worthwhile to note that when we do experience our first period after giving birth, the menstruation may not be regular (i.e., you may have your period this month but not again until the third month) and the intensity of the bleeding may also differ from your pre-pregnancy periods. There is also a chance of ovulating before menstruation (i.e., the bleeding), so breastfeeding mothers can be fertile before they experience their period physically. These are all factors that differ from woman to woman.

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