One aspect of the breast rediscovered ... Breastfeeding: a method of spacing?
At the beginning of the century nobody was surprised at the long periods of amenorrhea experienced by women when pregnancies and lactations followed each other. Professor Pinard, famous gynecologist, said in 1909: "The woman in the state of nature, healthy woman, should never be set." For centuries, the contraceptive role of breastfeeding is known. In all mammals whose reproduction is not seasonal, it is based on lactation as child spacing, it is 4 to 5 years in apes. By cons, in women, the role of breastfeeding is often denied, the contraceptive effect of breastfeeding are put down to maternal malnutrition or sexual abstinence ... And even those who admit the impact of lactation remain skeptical about its effectiveness at the individual level, because they all met at one time or another a woman who became pregnant while breastfeeding.
Epidemiological studies on the subject are numerous and relate to the 5 continents. Many of them have methodological problems. However, there is revealed evidence of a clear link between breastfeeding and fertility. This link is independent of ethnic origin, similar observations were made in various primitive peoples, but also in women Canadian, Swedish, Australian ... from the time when breastfeeding has the same characteristics. The contraceptive effect is greatest in women who practice an intensive and prolonged breastfeeding, regardless of ethnic or geographical origin.
The physiological basis of this infertility are not yet fully known. Ovarian function is blocked, with more or less complete inhibition of follicular development.
Two theories exist:
The hormonal theory, the more conventional infertility attributed to hyperprolactinemia
The neural theory, more recent emphasis on the neuro-sensory phenomena caused by the sucking of the breast. It would cause an alteration of GnRH secretion via mediators (catecholamines or opioids).
Anyway, this is an unrestricted breastfeeding, by which the mother fulfills all the needs of the sucking child, that will provide maximum contraceptive effectiveness. Maternal nutritional status would have little impact on fertility, this impact could be explained by changes in the practice of breastfeeding, or by an influence of nutrition on lactation. Research in this area are to continue.
Current knowledge can offer women a real family planning method. The LAM (Breastfeeding and Amenorrhea), developed at the Bellagio consensus, gives a pregnancy rate below 2% during the first 6 months postpartum, with 3 conditions:
- child under 6 months
- exclusive breastfeeding or almost exclusive
- absence of menses
The integration of LAM in the panoply of methods of birth control in our country is interesting for couples who want a method "green" friendly female physiology. It has a vital interest in developing countries, where it is statistically the most effective method. In these countries, the decline of breastfeeding is a disaster not only for child health, but also demographically. Environmental challenges are not insignificant: in Mexico.
One can also wonder about the long-term consequences for our species, endocrine changes induced by the "bottle-feeding culture". It was calculated that women "primitive" at the end of their reproductive period, between their pregnancies and lactations, were exposed to a hyperprolactinemia for 16 years, this period being only 16 months on average for women "modern". Estrogens and b-endorphins are also concerned. We have yet to discover what is the impact of such changes on the health of women and their psycho-physiology.