Lactational amenorrhoea method (LAM)

The lactational amenorrhoea method (LAM) is the use of breastfeeding as a contraceptive method. Lactational means breastfeeding and amenorrhoea means not having monthly bleeding. In this case, there is a delay in ovulation caused by the action of prolactin hormone from the effect of lactation or breastfeeding. An infant's suckling of the nipple sends neural signals to the mother's hypothalamus (part of the brain), which influences the anterior pituitary gland to secrete prolactin to stimulate the breast for milk production. This, in turn, inhibits the secretion of follicle stimulating hormone (FSH) and luteinizing hormone (LH), and as a result ovulation does not occur. While women are exclusively breastfeeding, prolactin continues to be secreted and pregnancy is unlikely. When prolactin levels decrease, the woman's monthly bleeding may return, and if she continues to have unprotected sexual intercourse she may get pregnant.

But the duration of suppression of ovulation is quite variable, depending on the breastfeeding status of the mother and the condition of the infant. To be fully effective the following three conditions must be met:

1. The woman's menstrual period must not have returned.
2. The baby must be exclusively breastfed frequently, day and night. Exclusive breastfeeding, means the infant receives no food or fluids other than breastmilk.
3. The baby must be less than six months old. This is because from six months onwards the baby needs to begin receiving complementary foods while continuing to be breastfed. The reduction in the amount of suckling at the breast may affect the hormonal mechanism, resulting in ovulation and menstruation returning, indicating a return of the woman's fertility.

If any one of these three criteria changes, another contraceptive must be started immediately to prevent an unwanted pregnancy, and to ensure healthy birth spacing of at least three years.

Factors affecting LAM

Any factor that causes a decrease in suckling can result in the return of ovulation and decreased milk production. These factors include supplemental feeding of the infant, reduction in the number of breastfeeds or long intervals between breastfeeds, maternal stress and maternal/child illness. In these cases, the client should not rely on LAM.

Advantages and disadvantages of LAM

The advantages and disadvantages of LAM are summarised in Table 4.3.

Table 4.3 Advantages and disadvantages of LAM.

Effectiveness of LAM

If the woman follows the method correctly — it is 98–99% effective (Family Planning: A Global Handbook for Providers, WHO, 2007).

Important points about LAM

Women should use both breasts to breastfeed their babies on demand, with no more than a four hour interval between breastfeeds during the daytime, and no more than a six hour interval between breastfeeds during the night-time. If they are unable to fulfil these conditions, you should advise and provide them with a complementary family planning method. If a woman has any risk of STI/HIV infection, you should advise her to use condoms.

If a woman wants to continue using LAM as a contraceptive method, but she fails to fulfill the LAM criteria, you should offer her advice on a complementary contraceptive method. In this case, the best choice would be a non-hormonal contraceptive (condoms, spermicides, diaphragms, IUCDs, and voluntary surgical contraception), because they don't enter into the blood stream and interfere with breastmilk. If these non-hormonal contraceptives are not available, the next best choice would be to provide a progestin-only method, such as progestin-only pills, a DMPA injectable, or implants, as these do not interfere with breastmilk production. Note that contraceptive methods containing oestrogen reduce the production of breastmilk and generally are not recommended for lactating women.