Physical Therapy Intervention for Puerperal Mastitis

Breast and nipple pain in the past 24 hours will be assessed using the numerical rating scale (NRS). Participants will be asked to rate her breast pain and nipple pain from 0 to 10 (11 point scale), with 0 indicating no pain and 10 indicating the worst possible pain.

The degree of breast engorgement of the left and right breasts will be assessed using a six-point engorgement scale developed by Hill and Humenick. The higher scores indicate more severe breast engorgement (1=soft, no change, 2=slight change, 3=firm, non-tender, 4=firm, beginning tenderness, 5=firm, tender, 6=very firm and very tender).

The assessor will use a portable durometer to measure the hardness of left and right breasts. The participant will lie in a supine position and the durometer will be placed at 3 cm from both nipples in the 10 o'clock and 2 o'clock positions. The spring-loaded presser is pressed downwards until trigger switch on. Each position will be measured three times and the mean value will be obtained. The values range from 0-100. Higher values represent a worse outcome.

Core body and breast temperatures will be measured using a non-contact infrared thermometer on the central part of the forehead and in the area 3 cm from both nipples in the 10 o'clock and 2 o'clock positions, respectively. The temperature of each position will be measured three times and the mean value will be recorded.

The volume of mother's milk will be measured by an electric breast pump for 15 minutes. Milk volumes will be recorded by weighing the collecting bottle on an electronic digital scale to the nearest 0.1 gram before and after each expression.

Acceptability of the intervention program will be assessed immediately post-intervention using a short questionnaire with 5-point Likert scale response to questions of 'how acceptable did you find the physical therapy interventions used in this study?' and 'how would you rate your overall satisfaction with the physical therapy program?' from 1 to 5, with 1 indicating very low acceptability or satisfaction and 5 indicating very high acceptability or satisfaction. The number of participants who rate a 5 (i.e. very high) on acceptability and satisfaction will be counted and recorded.

Adverse events will be recorded and reported as per Institutional Review Board, National Cheng Kung University Hospital guidelines on reporting adverse events and serious adverse events, with the absence of adverse or serious adverse events related to the physical therapy intervention used to indicate safety of the trial protocol.

Breastfeeding self-efficacy will be evaluated using the Breastfeeding Self-Efficacy Scale - Short Form (BSES-SF). The BSES-SF is a validated and reliable patient-reported outcome measure consisting of 14 items. Each item is scored between 1-5 points with 1 indicating 'not at all confident' and 5 indicating 'always confident'. Total scores range from 14 to 70, with higher scores indicating higher breastfeeding self-efficacy.