Lactation Introduction

Breast milk is widely acknowledged to be the most complete form of nutrition for infants. Breastfeeding poses multiple benefits for infants including health, growth, immunity, and development. Specific infant benefits of breastfeeding include decreased episodes of diarrhea, respiratory infections, and ear infections. Breastfeeding poses multiple maternal benefits as well, including a reduction in postpartum bleeding, earlier return to prepregnancy weight, reduced risk of premenopausal breast cancer, and reduced risk of osteoporosis [34]. In order to encourage breastfeeding, the Health and Human Services "Healthy People 2010" initiative targets increasing the percentage of mothers who breastfeed to 75% in the early postpartum period, 50% at six months, and 15% at one year [35]. Professional medical organizations encourage breastfeeding as well [36, 37]. The American Academy of Pediatrics (AAP) considers breastfeeding to be the ideal method of feeding and nurturing infants and recommends that all women breastfeed and continue to do so until the child reaches one year of age [37].

As in pregnancy, it is highly likely that a woman will require and take medications while she is breastfeeding. Surveys in various European countries demonstrate the extent of drug use by lactating/breastfeeding women. Postpartum women who choose to breast feed take fewer medications than those who do not breastfeed [38]. Most nursing mothers (90-99%) receive a medication during the first week postpartum, 17-25% of nursing mothers take medication at four months postpartum, and 5% of nursing mothers receive long-term drug therapy [39].

When lactation studies are undertaken, the emphasis is usually on the health risk or extent of exposure in the breast-fed infant, failing to investigate maternal factors such as pharmacokinetics, dose adjustments, or other clinically relevant information that affect the efficacy or safety in breastfeeding women. Potential differences in PK might be expected in the postpartum and lactating periods due to differences in endogeonous hormones, total body weight, body fat, and muscle mass compared to nonlactating women.

Inconsistent and inadequate methodologies are often employed in lactation studies. Many studies have shortcomings such as an extremely small sample size with infrequent or single-time point sampling, thus making interpretation or comparison across studies quite difficult. The consistent application of adequate study designs should improve both the quality and quantity of data available, and assist patients and health care providers when making decisions about the use of drugs in lactating women.

The mere presence of a drug in breast milk does not necessarily indicate a health risk for the breast-fed infant. The presence or absence of the drug in milk is only the first step in determining risk. The extent of exposure to a drug in the breast-fed infant may be considerably less than anticipated by drug excretion into breast milk due to decreased bioavailability of drug in milk (e.g., tetracycline). In addition, the known or anticipated effects on the breast-fed child of drug exposure through breast milk will aid in the risk analysis. Unwarranted recommendations to stop nursing will negate the benefits of breastfeeding to both the mother and the child.

Clinical lactation studies can be designed to address different lactation issues such as PK/PD changes in lactating women, extent of drug transfer into breast milk, extent of drug transfer via breast milk to the breast-fed child, drug effect on milk (e.g., production and composition), and effects of drug exposure from breast milk on the breast-fed child. This section addresses considerations in the design of clinical lactation studies. The design for safety studies in the breast-fed child specifically studying the effects on the breast-fed child of drug exposure through breast milk is beyond the scope of this section.

New Mothers Guide to Breast Feeding

New Mothers Guide to Breast Feeding

For many years, scientists have been playing out the ingredients that make breast milk the perfect food for babies. They've discovered to day over 200 close compounds to fight infection, help the immune system mature, aid in digestion, and support brain growth - nature made properties that science simply cannot copy. The important long term benefits of breast feeding include reduced risk of asthma, allergies, obesity, and some forms of childhood cancer. The more that scientists continue to learn, the better breast milk looks.

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