Breastfeeding and Fertility throughout History
Lactation Amenorrhea means the absence of menstruation while breastfeeding. The role of breastfeeding in delaying the return of menstruation and decreasing of fertility has been known for centuries. Aristotle, in his Historia Animalium Book VII, written in 350 B.C, says “Women continue to have milk until their next conception; and then the milk stops coming and goes dry, alike in the human species and in the quadripedal vivipara. So long as there is a flow of milk the menstrual discharge does not take place as a general rule, though the discharge has been known to occur during the period of suckling”. He continues the same subject in book V, noting that women may become pregnant while lactating: “While women are suckling children, menstruation does not occur according to nature, nor do they conceive; if they do conceive, the milk dries up”.
Dr. Roger Short reminds us of these famous quotations in his elegant series of articles on Breastfeeding, Fertility and Population Growth, also reflecting the wide spread perception that breastfeeding is not a reliable contraceptive method for every woman.
The understanding of the link between the mode of infant feeding and child survival, as well as the evidence on how normal breastfeeding patterns are interfered with can be traced back throughout human history from historical and even mythological sources. Both Moses and Mohammed survived because of wet-nurses after being rescued. Romulus and Remus, mythological founders of Rome, were suckled by a wolf and Zeus was suckled by a goat. Among the Pharaonic Egyptians, Babylonians and Hebrews, breastfeeding lasted about 36 months and 24 months in Byzantine and Islamic countries. The wealthier Romans and Greeks hired wet-nurses (the Romans had 16-month wet nursing contracts and the Greeks had 6-month contracts) to ensure the child’s survival (Short, 1992). It has been noted that if women stop breastfeeding due to the child’s death or any other reason, the women would soon become pregnant.
Breastfeeding and Fertility and the !Kung
A very good illustration of breastfeeding related infertility is derived from studies of the hunter- gathering societies in Africa, Australia and South America. Nancy Howell of the University of Toronto in her study of the !Kung of the Kalahari Desert of Southern Africa has shown that the !Kungs, “who use no modern forms of contraception and have no fertility-regulating practices such as late marriage, taboo on intercourse during lactation or infanticide, average 4.7 children and a mean birth interval of 4.1 years”. Further studies on the breastfeeding pattern revealed that the frequency of breastfeeding was about 4 times per hour, with frequent night suckling, even while the mother was sleeping, with a total duration of breastfeeding for 3-4 years. The same breastfeeding pattern was found in Papua New Guinea and is considered as “normal” for human species, as human milk is low in fat and protein and frequent suckling is necessary to ensure adequate nutritional supply to cover the needs of the fast growing infant. The same pattern of breastfeeding and a birth interval for four or five years have been found in chimpanzees and gorillas, which share about 98% of genetic information with humans (Short,1984).
Breastfeeding, Fertility and Child Spacing in the Modern World
Returning to the modern world, we have to admit that there are rare societies from the developed and even the developing world who keep up the same breastfeeding frequency and between birth intervals. This is so, even though it is estimated by WHO that breastfeeding contributes to natural birth spacing, providing 30% more protection against pregnancy than all the organized family planning programs in the developing world (Kleinman1987; WHO, 1993 and 1996). Hospital practices that separate the mother and child after birth, early supplementation; poor or no knowledge of breastfeeding management; absence of family or community support, often combined with the mother’s early return to the workforce; all interfere with an optimal breastfeeding pattern and subsequently are causing early unwanted pregnancies, if no other contraceptive is available.
Short duration of breastfeeding, in turn, increases maternal and infant mortality and morbidity. There is gross evidence to show that a birth interval of two or more years significantly enhances infant survival and reduces maternal morbidity. Dr Short, in analyzing data from 150,000 women from 29 countries in the World Fertility Survey, estimated that if mothers could space their pregnancies by an average of at least two years “the current annual total of 2.6 million deaths of children under one year of age might be expected to fall by at least 20% resulting in saving about half a million lives a year.”
Further decline of breastfeeding will increase monetary expenses related to fertility regulation. In 1988, Roger Short stated that, in his estimation, if the breastfeeding rate were to decline 25%, it would require almost a tripling of contraceptive prevalence in Senegal, a 38% increase in current contraceptive use in Indonesia and 7% in Mexico.
The Bellagio Consensus
Despite the variety of modern family planning methods available, many women do not use them. Breastfeeding appears to be an acceptable and culturally appropriate, non-invasive and cost-effective natural method of regulation against unwanted pregnancy. However, there was not enough scientific evidence to prove this, and therefore breastfeeding was not accepted until recently as a reliable contraceptive, despite a thousand years of its empirical effectiveness. In fact, for many years doctors told women that the adage “breastfeeding can delay a new pregnancy” was nothing less than a “grandmother” myth and that a modern woman should not rely on this “barbaric” method. Not surprisingly, a definition of the Lactation Amenorrhea method of contraception could not be found in any medical dictionary. In the 1980s, enough knowledge of lactation infertility had finally accumulated, a conference was held to discuss “under what circumstances a breastfeeding woman could postpone her pregnancy.” The conference attendees came to a consensus about the conditions under which breastfeeding can be used as a safe and effective method of family planning. This consensus is known as the “Bellagio Consensus,” named for the venue of the conference in Italy:
“the maximum birth spacing effect of breastfeeding is achieved when a mother ‘fully’ or nearly fully breastfeeds and remains amenorrhoeic. When those two conditions are fulfilled, breastfeeding provides more than 98% protection from pregnancy in the first six months”.
This set the definition of the Lactational Amenorrhea Method (LAM) as a family planning method and the algorythm for its use.
The three core questions for determining the appropriateness of the LAM for any mother are:
- Have your menses returned?
- Are you supplementing regularly or allowing long periods without breastfeeding either day or night?
- Is your baby more than six months old?
If a mother answers “YES” to one or more of the questions, she is advised to choose another contraceptive method, but is encouraged to continue to breastfeed. (Labbok, 1994; WHO, 1992)If a mother answers “NO” to all three, she can use the LAM, and she does not need a complementary contraceptive method, as there is only a one to two percent chance of pregnancy.
Another important conclusion derived from many studies done within the last 10 years on the LAM is that while breastfeeding alone is not a reliable contraceptive, the Lactational Amenorrhea Method is. Results of the WHO multicenter study confirmed that the 6 months lifetable pregnancy rates during the correct use of the LAM were less than 2%. An Australian study showed that the risk of pregnancy in those who remained amenorreheic was 1.7% at six months and 7% at 12 months, despite a mean age of introduction of complementary feeding in 5.3 months postpartum (Short 1991, Lewis 1991). These effects are comparable to the effect of other temporary methods of contraception: to the 6% of unwanted pregnancies in the first year of use of spermicides and diaphragms, in 3% in male condom users; 0.10% new pregnancies with perfect use of combined oral contraceptive pills at the end of the first year and 3% of new pregnancies among typical users (Kennedy 1998).
Those studies also confirmed that the LAM is a well-accepted contraceptive method, both in developed and developing countries, and has few or no disadvantages. Among the disadvantages named were short duration of use, complicated breastfeeding practice, especially night feeding, and absence of protection against Sexually Transmitted Diseases (STDs), particularly in areas with high incidence of HIV and Hepatitis C infections. On the positive side, among other advantages, the LAM can be a transitional or introductory family planning method especially among first users. It can also simultaneously promote exclusive breastfeeding and therefore increase its benefits for maternal/infant health, in addition to giving sound economical savings within a family and the community.
A second meeting in 1995 confirmed the Bellagio Consensus statement and all three LAM criteria. Experts carefully concluded that, under certain circumstances, “it may be possible to relax the requirement of full and nearly full breastfeeding” and “it may be possible to extend LAM beyond six months postpartum. ” The firm conclusion regarding the amenorrhea criterion confirmed that this criterion is not possible to eliminate and that “the end of amennorhoea is the clearest marker indicating increasing risk of pregnancy.”
Understanding the LAM
An understanding of the underlying mechanisms of the LAM, both by a health professional and a mother, is crucial for the LAM’s effectiveness and for successful protection against early pregnancy. Breastfeeding regulation of both menstruation and milk production begins with suckling and its effect on the hypothalamus. Nipple stimulation alters the pituitary hormonal production responsible for ovulation, by suppressing the release of the gonadotropin releasing hormone, which subsequently disorganizes the secretion of luteinising hormone and follicle stimulating hormone, which in turn suppresses ovulation. Concurrently suckling stimulates milk production by pituitary releasing of oxytocin and prolactin.
LAM at the Individual Level
While at the population level the LAM has been shown to be an effective and reliable contraceptive method, at the individual level, return of menses and fertility is highly variable. The WHO multinational Study of Breastfeeding and Lactation Amenhorrea results stated that “the duration of amenorrhea were substantial, ranging from a median of 4 months in New Deli (India) to 9 months in Cheggdu (China)” (WHO 1998). The Australian study (a well nourished population) revealed that mean duration of the anovulation was 322 days and 289 days of amenorrhea (Lewis,1991).
Both studies confirmed that women from developed countries are more likely to delay supplementation (around 5 months), whereas women from developing countries start supplementation much earlier, sometimes right after birth.
Frequency of breastfeeding and breastfeeding pattern (duration of each feed, interval between feeds as well as the strength of suckling), introduction of food other than breast milk, even the time when the supplement is given (before or after breastfeeding), can interfere with the resumption of menses. “The risk of a first menses increased substantially once 50% of the total number of feeds the infant received consisted of supplements” (WHO, 1998). Night feeding is likely to be a very important determinant of the prolonged amenorrhea, together with full or nearly full breastfeeding.
The use of pacifiers, the use of bottles, the introduction of solids or fluids, long intervals between feedings, the absence of night feedings, or anything else that interferes with suckling can both decrease milk production and stimulate ovulation. Sick infants, premature infants, infants with cleft lip/palate can experience difficulties with suckling, and mothers of these children should pay extra attention to ensure enough nipple stimulation. In the absence of lactation, ovulation resumes on an average of six to seven weeks postpartum, when the woman becomes fertile again.
As mentioned above, there are three conditions under which the LAM provides 98% protection:
1) No menstruation
2) Before 6 months postpartum
3) Frequent unrestricted breastfeeding, including night feedings
If any of those conditions are not met, the mother should immediately start to use an additional method of contraception if she does not wish to become pregnant. A mother should be advised to use breastfeeding compatible methods. If hormonal methods are chosen, the mother should be informed that pills containing estrogen may decrease her milk supply, and therefore should be avoided.
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Hight-Laukaran V, Labbok MH, et al., 1997. Multicentral Study of the Lactational Amenorrhea Method (LAM):II. Acceptability, Utility, and Policy Implications,Contraception 55 (6): 337-346.
Institute for Reproductive Health, 1995. Consensus staetement on the Lactational Amenorrhea Method for family planning (Conference held Bellagio, Italy 11-14 Dec,1995), Institute for Reproductive Health, Georgetown University Medical Centre.
Kennedy KI, Kotelchuck M 1998, Policy considerations for the introduction and promotion of the Lactation Amenorrhea Method: advantages and disadvantages of LAM. J Hum Lact 14(3):191-203.
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