Invited Commentary: Mastitis While Breastfeeding: Old Theories and New Evidence

Ruth A. Lawrence

From Department of Pediatrics, Obstetrics, and Gynecology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642 (e-mail: ruth_lawrence{at}urmc.rochester.edu).


    INTRODUCTION
 TOP
 INTRODUCTION
 REFERENCES
 
In the last decade, significant effort has been expended to increase the frequency and duration of breastfeeding in the United States (1Go) and throughout the world (2Go). Gradually, the number of women leaving the hospital breastfeeding in the United States has increased to more than 60 percent (3Go). The health goals of our nation for the year 2010 target 75 percent of women breastfeeding at hospital discharge, 50 percent still breastfeeding at 6 months, and at least 25 percent breastfeeding for a year (1Go). One of the side effects of increased incidence of breastfeeding has been an increased incidence of lactational mastitis (4Go). The medical literature is lean on this subject, however. The few reports that have been published in the past 20 years are a small series (5GoGo–7Go). Earlier work on mastitis emanated from the staphylococcal epidemic of the 1960s when hospital nurseries were plagued with staphylococcal infections, and both lactating and nonlactating women developed mastitis (8Go). As a result, consistent evidence of diagnostic findings and successful management of mastitis is difficult to locate. Much misinformation exists in classic textbooks, and many cases reported presently have been treated over the telephone without the benefit of being seen by a health care provider (9Go).

The report, "Lactation Mastitis: Occurrence and Medical Management among 946 Breastfeeding Women in the United States," by Foxman et al. (10Go) makes a major contribution to the medical literature. The authors recruited patients from a large family birthing center in Michigan and the employees of a large company in Nebraska. The participants were initially recruited during pregnancy, thus creating a prospective study of the incidence of mastitis in a large group of breastfeeding women. This allowed for estimation of the incidence of mastitis and the specific circumstances under which it occurred. The participants were contacted again 3 weeks postpartum, and their verbal consent was confirmed. They were interviewed at 3, 6, 9, and 12 weeks postpartum or until they ceased breastfeeding. Participants were given a small gift as an incentive after each interview. The diagnosis of mastitis was defined by self-reported symptoms diagnosed by a health care provider, usually by telephone. The accuracy of this definition was tested against other modalities, including antibiotic prescription.

In this cohort of almost 1,000 women, 9.5 percent of the population experienced mastitis at least once in the first 3 months postpartum. Although the strongest risk factor was a history of mastitis with a previous infant, nipple cracks and sores prior to the mastitis, the use of antifungal nipple cream, and feeding the baby more frequently than usual were key associated phenomena. For women with no prior history of mastitis, the use of a manual breast pump during the same week was significant. In contrast to other studies, the incidence was similar in all sociodemographic variables, including maternal age (5GoGo–7Go). When this finding is compared with the few other studies, it is important to note that the definition of mastitis was different in the other studies, the observation time was longer in one (6 months), but the number of participants in the studies was smaller (5GoGo–7Go). An additional, striking finding in the report was that mothers with a previous history of breastfeeding and a previous history of mastitis had a higher incidence with this infant. When one compares the standard breastfeeding recommendations, it is important to note that this study found that frequent, short feedings were more apt to be associated with mastitis than were longer, less frequent feedings (11Go). While washing nipples before and after feedings was not related to mastitis, the authors did not study hand-washing practices (10Go). More than a third of the women reported nipple cracks and sores in the first week postpartum.

The significant points in this study are that mastitis does occur in almost 10 percent of the population of healthy, normal women. Further, sociodemographic factors do not appear to play a role. It is important to note that many of these cases were diagnosed by telephone, and antibiotics were prescribed without benefit of examination or culture. While Foxman et al. (10Go) do not report any effect of mastitis on early weaning, it has been reported in other studies (11Go). Associated factors of nipple cracks and sores are important in terms of potential for preventive measures such as more aggressive treatment of cracked nipples and special consideration of breastfeeding techniques at that time. While it is reported that increased frequency of feeding is associated with the incidence of mastitis, that contradicts earlier findings that suggest that undue length of time between feedings may precipitate mastitis. Examples such as the first time the baby sleeps through the night or the first time the mother leaves her baby and does not have an opportunity to pump for many hours have long been associated with the first bout of mastitis (5Go, 11Go). These points deserve further investigation.

It is clear from this study that hand pumps can predispose to mastitis. This has been the impression of many breastfeeding professionals for many years (4Go). All hand pumps, however, are not equal, and those that are available with a soft, pliable flange may not be the culprits. The authors do not describe the hand pumps.

The higher incidence of mastitis among women who had had mastitis before would lead one to investigate any significant differences in maternal anatomy, breastfeeding techniques, and colonization with potential pathogens. This study did not include bacteriologic identification.

Building on this firm foundation, additional studies should address the timing and frequency of feedings, the effects of hand washing, and bacterial trends.

Foxman et al. relied on the mother's report of mastitis, and 64 percent of the mother's relied on a telephone diagnosis by physicians (59 percent), nurses (23 percent), and others. There is no indication of which health care professional the other 36 percent saw in person. The diagnostic methodology creates a problem of validity. An important study would involve a small cohort of cases who were actually seen by a trained, board-certified lactation consultant to determine accuracy of the telephone diagnosis. The final step would be a case-control study to determine the reproducibility of these findings, especially those that are counter to traditional thinking.


    NOTES
 TOP
 INTRODUCTION
 REFERENCES
 
(Correspondence to Dr. Ruth A. Lawrence at this address).


    REFERENCES
 TOP
 INTRODUCTION
 REFERENCES
 

  1. United States Department of Health and Human Services. Healthy people 2010. (Conference edition, in two volumes). Washington, DC: United States Department of Health and Human Services, 2000.
  2. World Health Organization/United Nations Children's Emergency Fund (UNICEF). Innocenti declaration on the protection, promotion, and support of breastfeeding. In: Breastfeeding in the 1990's: a global initiative meeting in Florence, Italy and New York. Geneva, Switzerland: World Health Organization, United Nations International Children's Emergency Fund, 1990.
  3. Ryan AS. The resurgence of breastfeeding in the United States. Pediatrics 1997;99:E12. (www.pediatrics.org).
  4. Lawrence RA, Lawrence RM. Breastfeeding: a guide for the medical profession. Sixth ed. St Louis, MO: C. V. Mosby, 1999.
  5. Fetherston C. Characteristics of lactation mastitis in a Western Australian cohort. Breastfeed Rev 1997;5:5–11.[Medline]
  6. Jonsson S, Pulkkinem MO. Mastitis today: incidence, prevention, and treatment. Ann Chir Gynaecol Suppl 1994;208:84–7.[Medline]
  7. Kinlay JR, O'Connell DL, Kinlay S. Incidence of mastitis in breastfeeding women during the six months after delivery: a prospective cohort study. Med J Aust 1998;169:310–12.[ISI][Medline]
  8. Devereux WP. Acte puerperal mastitis: evaluation of its management. Am J Obstet Gynecol 1970;108:78–81.[ISI][Medline]
  9. Bowes WA. Postpartum care. In: Gabbe SB, Niebyl JR, Simpson JL, eds. Obstetrics normal and problem pregnancies. 3rd ed. Livingstone, NY: Churchill, 1996:70–1.
  10. Foxman B, D'Arcy H, Gillespie B, et al. Lactation mastitis: occurrence and medical management among 946 breastfeeding women in the United States. Am J Epidemiol 2002;155:103–14.[Abstract/Free Full Text]
  11. Riordan JM, Nichols FH. A descriptive study of lactation mastitis in long-term breastfeeding women. J Hum Lact 1991;6:53–8.
Received for publication July 30, 2001. Accepted for publication August 28, 2001.


Related articles in Am. J. Epidemiol.:

Lactation Mastitis: Occurrence and Medical Management among 946 Breastfeeding Women in the United States
Betsy Foxman, Hannah D'Arcy, Brenda Gillespie, Janet Kay Bobo, and Kendra Schwartz
Am. J. Epidemiol. 2002 155: 103-114. [Abstract] [FREE Full Text]  




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