To explore influencing factors of puerperal mastitis (PM) in puerperae.

A total of 1 162 puerperae who gave birth in a tertiary hospital for women and children in Chengdu from September 1 to December 31, 2020 and were followed up for 42 days after delivery were selected as research subjects. According to occurrence of PM within 42 days after delivery or not, they were divided into PM group (n=103) and control group (n=1 059). Self-designed Questionnaire on Influencing Factors of Postpartum Mastitis (hereinafter referred to as the Questionnaire), and Chinese Simple Profile of Mood States (POMS) Scale (hereinafter referred to as the POMS Scale) were used for investigation in two groups. The Questionnaire mainly included 50 items in 10 dimensions: general demographic data, pregnancy and disease, perinatal drug use, breastfeeding, diet and living habits, and so on. The POMS Scale included 40 items in 7 dimensions of anxiety and so on. Items in the Questionnaire and scores of POMS Scale were compared between two groups by independent-samples t test, chi-square test and Fisher′s exact test. The procedures followed in this study complied with requirements of the Medical Ethics Committee of cases collected hospital, and was approved by its Ethics Committee[Approval No. 2021(29) of Scientific Research Review], and each subject signed an informed consent form for clinical research. There were no significant differences in general clinical data between two groups, such as maternal age, and so on (P>0.05).

①The incidence of PM in puerperae included in this research was 8.9% (103/1 162), and incidences of PM in the 3rd and 4th weeks after delivery were the highest as 2.7% (31/1 162) and 2.4% (28/1 162), respectively. ②Proportion of iron supplementation and oral probiotics during perinatal period, constituent ratio of cracked nipple degree, time and frequency of using breast pump, frequency of using nipple shield and nipple protection cream, rate of correct breastfeeding connection posture, degree of breast pain during breastfeeding, and composition ratio of breastfeeding underwear wearing conditions of two groups were statistically significant (P<0.05). ③Anxiety score of POMS Scale in PM group was (7.1±5.0) points, which was significantly higher than that in control group (5.3±4.1) points, and the difference was statistically significant (t=-3.540, P=0.001). ④A total of 10 influencing factors were included for multivariate unconditional logistic regression analysis for influencing factors of PM based on factors with statistically significant differences in univariate analysis of the above influencing factors of PM, existing research results and clinical experience. Results of multivariate unconditional logistic regression analysis showed that independent risk factors for PM in puerperae included: iron supplementation during perinatal period (OR=3.351, 95%CI: 1.949-5.758, P<0.001), cracked nipple (OR=3.564, 95%CI: 1.909-6.654, P<0.001), frequency of using breast pump>once a day (OR=5.102, 95%CI: 1.047-24.876, P=0.044), frequency of using nipple protection cream>once a day (OR=2.147, 95%CI: 1.156-3.987, P=0.016), incorrect breastfeeding connection posture (OR=2.311, 95%CI: 1.202-4.445, P=0.012), uncomfortable wearing of nursing underwear (OR=2.322, 95%CI: 1.008-5.347, P=0.048), without wearing nursing underwear (OR=3.516, 95%CI: 1.821-6.789, P<0.001), high anxiety score (OR=1.073, 95%CI: 1.007-1.143, P=0.029), and independent protective factor was oral probiotics during perinatal period (OR=0.110, 95%CI: 0.025-0.478, P=0.003).

Guiding perinatal puerperae to correct incorrect behaviors by formulating clinical intervention measures, such as misuse of perinatal iron supplements, breast pumps and nipple protection creams, improper wearing of nursing underwear and irregular breastfeeding behaviors, advocating oral administration of probiotics during perinatal period and relieving anxiety are of great significance for prevention of PM in puerperae.