Statement on breast feeding,fertility and contraception

An important part of the human reproductive process, breastfeeding also plays a key role in infant nutrition while protecting the infant from exposure to infection. Breastfeeding also plays a major role in the natural regulation of fertility, but breastfeeding patterns are changing along with urbanization and lifestyle changes. These changes are tending towards a shortening of the duration of breastfeeding, a reduction in the daily frequency of breastfeeding episodes, and an earlier introduction of food supplements. Consequently, the risk of pregnancy during lactation has increased. The literature suggests considerable variability in the length of breastfeeding and postpartum amenorrhea and in the duration of lactational infertility among different populations. Both the return of ovarian activity and fertility depends on the time elapsed since delivery. Variables that play a primary role in the length of amenorrhea and infertility include: the duration of breastfeeding the frequency and duration of suckling; the administration of supplements to the infant; the mother's nutritional status; and geographic, social, and cultural factors. Knowledge of local breastfeeding practices and the associated risks of pregnancy should be a prerequisite for those counseling nursing women. All women should be advised and encouraged to breastfeed fully, as far as is practicable. Women also need to be informed that it is difficult to predict exactly the duration of lactational infertility for each woman. The timing of the introduction of contraception depends on the risk factors and some programmatic aspects, such as the possibility that the woman may not return after delivery or after the 1st postpartum visit as well as the type of contraceptive chosen. Current information on the influence of contraceptive methods -- IUDs, oral contraceptives, injectable contraceptives, norplant, barrier methods, periodic abstinence, and sterilization -- upon breastfeeding are summarized.     

Breast feeding and future health

PURPOSE OF REVIEW: This review discusses the long-term health effects of breast feeding, based on the most relevant publications from the second half of 2004 and 2005. RECENT FINDINGS: The positive effect of breast feeding on later cognitive function continues to be the most consistent and important effect. Also, breast feeding is likely to protect against some immune-related diseases later in life, such as type 1 diabetes, coeliac disease, inflammatory bowel diseases and perhaps cancer. The evidence for an effect on allergic disease continues to be inconclusive. Furthermore, breast feeding seems to be associated with a lower blood pressure and serum cholesterol, but there is no clear association with cardiovascular disease or death. Most new studies and meta-analyses show a protective effect against later obesity, but this seems to be small. A new hypothesis suggests that breast feeding programmes the insulin-like growth factor axis and results in higher growth velocity later in childhood. SUMMARY: Evidence is increasing that breast feeding, beyond its well-established beneficial effects during the breast-feeding period, also confers long-term benefits. These effects are not strong at the individual level, but are likely to be of importance at the population level. Since the majority of the studies are observational, however, it is difficult to prove causality.     

Breast feeding and later psychosocial adjustment

The relationship between the duration of breast feeding and psychosocial outcomes measured between the ages of 15 and 18 years was examined in a birth cohort of 999 New Zealand children. During the period from birth to 1 year, information was collected on maternal breast-feeding practices. Between the ages of 15 and 18 years, sample members were assessed using a range of psychosocial measures, including measures of the quality of parent-child relationships, juvenile delinquency, substance abuse and mental health. Children who were breast fed for a longer duration were more likely to report higher levels of parental attachment and tended to perceive their mothers as being more caring and less overprotective towards them compared with bottle-fed children. No association was found between the extent of breast feeding and subsequent rates of juvenile offending, substance use and mental health in later life. Mothers who elected to breast feed were also more likely to be older, better educated, living with a partner, less likely to smoke during pregnancy, and to come from advantaged socio-economic backgrounds characterised by better living standards and a higher family income. Rates of breast feeding were also greater among mothers who gave birth to a first-born child of higher birthweight. After adjustment for these maternal and perinatal factors, the duration of breast feeding remained significantly associated with adolescent perceptions of maternal care, with increasing duration of breast feeding being associated with higher levels of perceived maternal care during childhood. It is concluded that: (a) it is unlikely that breast feeding is associated with reduced risks of psychiatric disorder in later life; (b) breast feeding may lead to closer parent-child relationships; and (c) it is unlikely that the association between breast feeding and cognitive development is mediated by intervening processes relating to improved psychosocial adjustment in breast-fed children.     

Breast feeding,growth and morbidity

The effect of exclusive breast feeding in the first few months of life on physical growth was studied prospectively in a group of 36 full-term healthy newborns. Growth failure was not observed in any infant until after the third month of life. The average growth curve for the entire group was between the 25th and 50th percentile at the end of the study period. However, faltering of growth as judged by weight at or below the tenth percentile of standard for age was seen in three (8%) infants at the age of four months, five (13%) at five months, eight (22%) at six months, nine (25%) at seven months, and twelve (33%) at eight months. Morbidity experience showed a slight but statistically higher frequency of respiratory infections and otitis in those infants who had shown faltered growth. Volume of milk intake was similar in the two groups. These observations suggest that a small proportion of exclusively breast-fed infants may not achieve adequate growth. In such infants, consideration should be given to supplementation after 4 months of age.     

特殊情况下的母乳喂养

本文从早产儿的母乳喂养;母乳喂养和黄疸;药物与哺乳;婴儿体重增长缓慢和母乳供应不足综合征;断奶——半流质和固体食品添加的过程;乙肝病毒携带者的哺乳问题分6方面讲解在特殊情况下的母乳喂养.     

Breast feeding,breast milk and AIDS

In response to concerns that breast milk can transmit human immunodeficiency virus (HIV) infection, the International Planned Parenthood Federation (IPPF) Acquired Immunodeficiency Syndrome (AIDS) Prevention Unit has developed a series of recommendations. A total of 5 infants have reportedly become infected as a result of breastfeeding when their mothers became infected with HIV in the immediate postpartum period. However, there are even more cases in which women in similar circumstances breastfed their infants and HIV infection was not transmitted. The infectivity of breast milk is probably dependent on factors such as the frequency or timing of appearance of HIV in breast milk, the viral titer, the mother's nutritional and immunologic status, maternal exposure to other viruses, parity, and the integrity of mucosal barriers. In addition, there are possible protective effects of breastfeeding, including reduction of the incidence and severity of diarrhea and gastrointestinal infection; reduction of the infection load and possible protection against the progression of HIV-related diseases; and the essential immunologic, nutritional, childspacing, and emotional benefits to the child. For all these reasons, it is recommended that breastfeeding by the biologic mother should be the feeding method of choice regardless of her HIV antibody status. If the mother cannot breastfeed, the use of pooled or alternative sources of human milk should be considered. In addition, further research is required to determine whether antibody in breast milk is protective and the factors that affect secretion of HIV in breast milk.     

Breast cancer detection in relation to oral contraception.

Analyses of tumor size and breast cancer stage were used to determine whether biased detection of breast cancer could have materially influenced estimates of risk associated with use of oral contraceptives. In a population-based case-control study conducted from 1980-1982, surveillance for breast cancer by breast exams, but not mammography, was found to be strongly linked to use of oral contraceptives. Tumors were slightly smaller and less likely to be late-stage (TNM stage III or IV) in patients who had used oral contraceptives. The net effect of any diagnostic bias on advancing the date of cancer diagnosis, whether from breast exams or other sources, was estimated to be less than 8 weeks. This corresponds to spuriously increasing the risk of early-occurring breast cancer in oral contraceptive users by at most 2.4% (relative risk = 1.024).     

Breast feeding and insulin-dependent diabetes mellitus in children

We have evaluated the hypothesis of a protective effect of human milk on the development of insulin dependent diabetes mellitus (IDDM). We studied the feeding histories of 95 diabetic children and compared them with controls consisting of their non-diabetic siblings and a pair matched group of nondiabetic peers of the same age, sex, geographical location, and social background. The incidence of breast feeding in diabetic children was 18%. This was similar to the control group. The duration of breast feedings was also similar among all three groups. There was no difference in the age of introduction of solid food between diabetic and nondiabetic children. Twice as many diabetic children, however, received soy containing formula in infancy as compared to control children. The mean age of onset of IDDM was not related to the type of feeding during infancy. The incidence of positive thyroid antibodies was two and one half times higher in formula-fed diabetic children than in breast-fed ones. In our studies we were unable to document any relationship between the history of breast feeding and subsequent development of IDDM in children.     

Breast feeding in infants with Down''s syndrome

Fifty-nine mothers of infants with Down's syndrome were interviewed about methods of early feeding and the problems encountered. Antenatally, 29 mothers had wished to breast feed and 16 were successful. According to the mothers, 31 babies had no difficulty in establishing sucking, 4 were slow for less than 1 week, 8 took 1 week and 16 took longer than 1 week. Severe cardiac anomaly was associated with poor sucking ability. It was concluded that infants with Down's syndrome do not inevitably have initial feeding problems and can be breast fed successfully, but their mothers need to persevere and to be given hospital support and encouragement.