Lactational Infertility in Family Planning

Abstract

The contraceptive effect of breast-feeding is the single most important determinant of human population growth rates in traditional societies without access to modern forms of contraception; lactational amenorrhoea is Nature's contraceptive. Even today, breast-feeding still prevents more pregnancies than all modern forms of contraception in many developing countries. Afferent neural inputs from the nipple pass via the spinal cord to the hypothalamus, where they cause a local release of β endorphin. This acts to depress GnRH secretion, thereby inhibiting pituitary gonadotrophin secretion, ovarian follicular development, ovulation and menstruation. The hypothalamic β endorphin release also inhibits dopamine production, resulting in increased pituitary prolactin secretion. The higher the suckling frequency, the more β endorphin that is released and hence the longer the duration of lactational amenorrhoea.

Lactational amenorrhoea can be relied up to give over 98% contraceptive protection to breast-feeding women in the first 6 months postpartum, regardless of their nutritional status or the time of first supplement introduction to the baby. This is because the first postpartum menstruation usually precedes the first ovulation during these early months. Once menstruation has resumed, lactation's contraceptive effect can no longer be relied upon, even though the woman continues to breast-feed. In breast-feeding women whose amenorrhoea extends beyond 6 months, there is an increasing tendency for the first ovulation to precede the first menstruation, thereby decreasing the reliability of lactational amenorrhoea as a contraceptive. Nevertheless, many women who continue to breast-feed may still have up to 1–2 years of good contraceptive protection from prolonged lactational amenorrhoea.

There is an urgent need to protect, promote and support breast-feeding in both developing and developed countries, not only for its contraceptive effect, but also for its many additional health benefits both for the mother, and for her child. A simple practical recommendation for developing and developed countries would be that for the first 6 months postpartum, the baby should be fed exclusively on breast-milk, and if the mother is amenorrheic, there is no need for her to use any other form of contraception. Whenever menstruation resumes, other forms of contraception are essential if pregnancy is to be prevented. After the baby's first teeth have erupted at around 6 months, breast-milk needs to be supplemented with other food, and lactational amenorrhoea needs to be supplemented with another contraceptive in order to ensure a spacing between births of at least 2 years, which is highly desirable for the health of the mother and her children.

Key Words:

• amenorrhoea
• breast-feeding
• contraception
• lactation