interfere with lactation. There are some medications that may stimulate the production of breast milk. These medications may be beneficial in cases where women with hypothyroidism may be unable to produce milk. A Cochrane review looked at the drug Domperidone (10 mg three times per day) with results showing a significant increase in volume of milk produced over a period of one to two weeks. However, another review concluded little evidence that use of Domperidone and Metoclopramide to enhance milk supply works. Instead, non-pharmacological approaches such as support and more frequent breastfeeding may be more efficacious. Finally, there are other substances besides medications that may appear in breast milk. Alcohol use during pregnancy carries a significant risk of serious birth defects, but consuming alcohol after the birth of the infant is considered safe. High caffeine intake by breastfeeding mothers may cause their infants to become irritable or have trouble sleeping. A meta-analysis has shown that breastfeeding mothers who smoke expose their infants to nicotine, which may cause respiratory illnesses, including otitis media in the nursing infant. Pesticides and other toxic substances bioaccumulate; i.e., creatures higher up the food chain will store more of them in their body fat. This is an issue in particular for the Inuit, whose traditional diet is predominantly meat. Studies are looking at the effects of polychlorinated biphenyls and persistent organic pollutants in the body; the breast milk of Inuit mothers is extraordinarily high in toxic compounds. The CDC has provided some resources for breastfeeding mothers to reference for safe medication use, including LactMed, Mother to Baby, and The InfantRisk Center. Market There is a commercial market for human breast milk, both in the form of a wet nurse service and as a milk product. As a product, breast milk is exchanged by human milk banks, as well as directly between milk donors and customers as mediated by websites on the internet. Human milk banks generally have standardized measures for screening donors and storing the milk, sometimes even offering pasteurization, while milk donors on websites vary in regard to these measures. A study in 2013 came to the conclusion that 74% of breast milk samples from providers found from websites were colonized with gram-negative bacteria or had more than 10,000 colony-forming units/mL of aerobic bacteria. Bacterial growth happens during transit. According to the FDA, bad bacteria in food at room temperature can double every 20 minutes.