A report «Amir LH, Forster D, McLachlan H et al. Incidence of breast abscess in lactating women: report from an Australian cohort. BJOG 2004;111(12):1378-81. »1 assessed the incidence of breast abscess in lactating women from 2 studies (a randomised controlled trial and a survey). A structured telephone interview was conducted to a total of 1193 primiparous women at 6 months postpartum in Australia. 207 women experienced mastitis and 171 were treated by antibiotics. Of the 1183 women who commenced breastfeeding, 0.4% (5/1183) experienced a breast abscess. All five had received antibiotics prior to abscess development, thus 2.9% (5/171) of women who took antibiotics for mastitis experienced a breast abscess.
A retrospective cohort study «Sugawara C, Yamana H, Sasagawa E, et al. Factors Associated with Surgical Treatment in Postpartum Women with Mastitis or Breast Abscess: A Retrospective Cohort Study. Breastfeed Med 2022;17(3):233-238»2 using the Japan Database assessed factors associated with requiring surgical treatment for mastitis or breast abscess in postpartum mothers (n=69 363). The proportion of mothers who were diagnosed with mastitis or breast abscess within 1 year after childbirth was 10.8% (7 516). 0.2% of all mothers and 1.5% of those diagnosed with mastitis or breast abscess underwent surgical treatment (n=114). Surgical treatment was significantly associated with mothers having their first child (adjusted OR, 2.58; 95% CI 1.63 to 4.07) compared to those with a second or later child; it was also significantly associated with the diagnosis of breast abscess (aOR, 10.38; 95% CI 5.28 to 20.40).
A retrospective cohort study «Duan Z, Xiao Q, Zhou J, et al. Risk factors for treatment failure in lactational mastitis: a retrospective cohort study in China. Int Breastfeed J 2025;20(1):83. »3 in China assessed risk factors for treatment failure in lactational mastitis. Among 133 patients, 93 (69.9%) were effectively treated with flucloxacillin, while 40 (30.1%) experienced treatment failure. Onset time ≥ 3 days (aOR 2.76, 95% CI 1.22 to 6.28) and inflammation located in the nipple/areola area (aOR 3.28, 95% CI 1.27 to 8.49) were independent risk factors for treatment failure. The treatment failure group had higher lactation suppression rates (20% vs. 2.2%, p = 0.001). Staphylococcus aureus was the predominant isolate, with a higher isolation rate in the treatment effective group,
A cohort study «Grzeskowiak LE, Saha MR, Ingman WV, et al. Incidence, antibiotic treatment and outcomes of lactational mastitis: Findings from The Norwegian Mother, Father and Child Cohort Study (MoBa). Paediatr Peri»4 in Norway studied mastitis in 79 985 mothers. The incidence of mastitis was 18.8%, with 36.8% reporting treatment with antibiotics. Women reporting early mastitis were less likely to report predominant breastfeeding (aRR 0.92, 95% CI 0.86 to 0.99) and any breastfeeding for 6 months (aRR 0.97, 95% CI 0.96 to 0.98) than women who did not report mastitis. Late-onset mastitis was not associated with poorer breastfeeding outcomes.