Mother's Milk: In Sickness and In Health?

Case Report

A 33-year-old G3P3 patient currently breastfeeding a 3-month-old infant presents with 2 days of vomiting, diarrhea, and fever as high as 101°F. She denies rash, joint pain, or conjunctivitis. She has not traveled outside of the country but returned from a trip to Texas 2 weeks ago. After recommending conservative treatment options for her acute illness, the patient asks whether she should continue breastfeeding her infant.

Based on current evidence you advise:

A. Stop breastfeeding but continue to pump and discard milk until illness resolves.

Discussion

Breastfeeding has historically been considered the natural method of infant nutrition. Before the 19th century, breastfeeding was practiced routinely. Most women either breastfed their infant or hired a wet nurse to complete the task, the latter being a more common practice among the wealthy. ¹ In the United States during the late 19th and early 20th centuries, rates of breastfeeding began to decline. The newly organized medical profession aspired to a more “scientific” approach to infant nutrition, promoting the use of artificial formula as a healthier and more complete form of nutrition. ^1,2

For several decades during the mid-20th century, physicians did not encourage breastfeeding and many women chose to not breastfeed their infants. Fortunately, a resurgence of breastfeeding occurred in the late 20th century. ^3,4 Support from multiple healthcare organizations including the World Health Organization (WHO) and the American Academy of Pediatrics as well as social mother-to-mother and peer-support programs, such as La Leche League and others, helped to significantly increase rates of breastfeeding. ^4,5 The U.S. Public Health Service has set national goals for breastfeeding in the “Healthy People 2020 goals,” striving for 82% of infants breastfeeding at birth, 60% at 6 months of age, and 34% at 1 year, whereas the WHO continues to recommend that a child breastfeed for at least 2 years. ⁶

Evidence-based research has established the benefits of breastfeeding. Human milk has been shown to be the optimal form of nutrition for human infants, changing as their nutrition needs change. ³ Breastfeeding has correlated with decreased childhood morbidity and mortality; one example includes a significant reduction in sudden infant death syndrome in breastfed infants. ^3,7,8 There are significant short-term benefits including decreased rates of common infections including otitis media, diarrhea, and lower respiratory tract infections, as well as decreased rates of less common infections such as necrotizing enterocolitis. ^8,9 Long-term health conditions in nonbreastfed children include increased risks of type 1 diabetes mellitus, obesity, asthma, allergies, celiac sprue, and childhood leukemia. ^{8,10 –12}

Maternal benefits of breastfeeding have also been well established. Short-term benefits include increased rates of maternal weight loss as well as decreased rates of maternal depression. ^13,14 Breastfeeding stimulates the release of oxytocin, which is believed to reinforce maternal instinct, strengthening the mother–infant bond. ¹⁵ Additional studies continue to support decreased risks of chronic medical problems, including type 2 diabetes mellitus, hypertension, rheumatoid arthritis, and decreased risk of breast and ovarian cancer. ^{16 –19}

Broader societal benefits of breastfeeding include decreased work absenteeism, increased employee retention, and overall reduced healthcare spending. ²⁰ The United States Department of Agriculture (USDA) estimates a $3.6 billion reduction in healthcare costs and $48 million reduction in Women, Infants and Children (WIC) funding if 75% of women breastfed for 3 months. ²¹

Breastfeeding and Maternal Infections

In general, the WHO recommends continuing to breastfeed during most maternal infections. Once the breastfeeding mother develops symptoms of infection, her infant has already been exposed to the pathogen. Discontinuing breastfeeding at that point deprives the infant of specific antibodies already present in the breast milk and increases the infant's risk of becoming ill; additionally, the antibodies from breast milk protect the infant from future infection. ²²

There are a limited number of maternal infections that require temporary breastfeeding cessation. One example is herpes simplex, in which case women must stop breastfeeding only if there are active lesions on the breast. Expressed milk may still be given and breastfeeding may resume once lesions have resolved. ^4,5 Another example is varicella infections, which require infant and mother separation when acquired within 5 days antepartum or 2 days postpartum. Once the infant has been given varicella-zoster Ig, expressed milk may be given to the infant as long as the milk does not come in contact with lesions. ^4,5 Also, women with active tuberculosis should be separated from their infants until infants are receiving isoniazid and mothers are receiving therapy; however, expressed milk may still be given to the infants. Mothers may resume breastfeeding after being treated for a minimum of 2 weeks and negative sputum samples are obtained. ²³ Lastly, the Centers for Disease Control and Prevention (CDC) recommends that faculties consider separating mothers with suspected or confirmed influenza from their infants. The appropriate length of temporary separation has not been determined and should be determined on an individual basis, again expressed breast milk can be given. ^4,24

Breastfeeding is contraindicated with HTLV types 1 and 2. ²⁵ This retrovirus, actively transmitted in Africa, South and Central America, and parts of Asia, causes devastating disease including adult T cell leukemia/lymphoma as well as HTLV-associated myelopathy/tropical aplastic paraparesis. ²⁶ The disease is asymptomatic early in life and is, therefore, silently transmitted via breastfeeding, sexual relations, and blood transfusions. ²⁷

HIV is also transmitted via breast milk with rates of mother-to-child transmission between 15% and 20% during prolonged breastfeeding when HIV transmission reduction strategies are not utilized. ²⁸ Westernized countries with available alternatives to breast milk discourage HIV-infected women from breastfeeding. In third world countries with high infant mortality rates secondary to infectious disease, the benefits of breastfeeding likely outweigh the risks of acquiring HIV; recent research also shows that the combination of exclusive breastfeeding and antiretroviral medications together may be the most effective way to decrease transmission while continuing to give infants the protective benefits of breast milk. ^29,30

The advent of the Zika virus has raised additional concerns regarding safety of breastfeeding. The Zika virus has been found in breast milk; however, at the time of publication there have been no cases of Zika virus being transmitted to infants via breast milk. ³¹ The WHO and CDC encourage mothers with Zika virus infection and mothers living in areas with ongoing Zika virus transmission to breastfeed their infants. ^31,32

Answer

How should you advise your patient? The correct answer is B: continue to breastfeed with the current maternal infection. Answer A is incorrect because the antibodies provided in the mother's breast milk will help protect the infant from developing the infection and prevent future infection. Answer C is incorrect because breastfeeding is contraindicated in HTLV-1 and herpes simplex with active lesions on the breast. Breastfeeding in HIV-infected patients living in the United States is also not advised as there is adequate access to alternative, effective methods of infant nutrition. Answer D is also incorrect because breastfeeding currently is recommended in women with Zika virus infections as there is no evidence of Zika virus transmission via breast milk.