Table 1 Participant characteristics

Age (year), mean ± SD

34.5 ± 3.3

33.6 ± 3.7

34.2 ± 4.4

BMI (kg/m2), mean ± SD

24.6 ± 3.4

24.1 ± 3.7

24.0 ± 3.7

Waist-hip ratio, mean ± SD

0.83 ± 0.04

0.82 ± 0.06

0.82 ± 0.04

Days after delivery, mean ± SD

16.8 ± 9.7

28.2 ± 34.8

31.9 ± 23.9

Married, n (%)

12 (100)

12 (100)

13 (100)

Living arrangement, n (%)

 With spouse

3 (25)

1 (8.3)

1 (7.7)

 With child (including spouse)

9 (75)

11 (91.7)

12 (92.3)

Highest level of education, n (%)

 Master degree

2 (16.7)

5 (41.7)

5 (38.5)

 Bachelor degree

9 (75.0)

7 (58.3)

7 (53.8)

 Associate degree

1 (8.3)

0 (0)

0 (0)

 Senior high school

0 (0)

0 (0)

1 (7.7)

Employment status, n (%)

 Full-time

9 (75.0)

9 (75.0)

10 (76.9)

 Part-time

0 (0)

0 (0)

1 (7.7)

 None

3 (25.0)

3 (25.0)

2 (15.4)

Smoking status, n (%)

 Never smoked

12 (100)

12 (100)

12 (92.3)

 Ex-smoker

0 (0)

0 (0)

1 (7.7)

Medical history*, n (%)

 None^a

8 (33.3)

8 (66.7)

12 (92.3)

 Cold intolerance

1 (8.3)

0 (0)

0 (0)

 Migraine

1 (8.3)

2 (16.7)

0 (0)

 Dermatitis

1 (8.3)

0 (0)

0 (0)

 Eczema^a

4 (33.3)

0 (0)

0 (0)

 Breast surgery

0 (0)

1 (8.3)

0 (0)

 Ankyloglossia

0 (0)

0

1 (7.7)

 Other

2 (16.7)

2 (16.7)

0 (0)

Medication, n (%)

 None

9 (75.0)

5 (41.7)

7 (53.8)

 Chinese medicine

0 (0)

1 (8.3)

1 (7.7)

 Lecithin

0 (0)

0 (0)

1 (7.7)

 Butin

1 (8.3)

0 (0)

0 (0)

 Antibiotics

1 (8.3)

1 (8.3)

2 (15.4)

 Pain killer

2 (16.7)

3 (25.0)

3 (23.1)

 Antihistamine

1 (8.3)

0 (0)

0 (0)

 Stool softener

0 (0)

1 (8.3)

0 (0)

 Anti-inflammatory

0 (0)

1 (8.3)

0 (0)

 High blood pressure drug

0 (0)

1 (8.3)

0 (0)

 Uterotonic drug

0 (0)

1 (8.3)

0 (0)

Gravidity, n (%)

 1

5 (41.7)

6 (50.0)

5 (38.5)

 2

6 (50.0)

4 (33.3)

3 (23.1)

 3

0 (0)

1 (8.3)

4 (30.8)

 4

0 (0)

1 (8.3)

1 (7.7)

 5

1 (8.3)

0 (0)

0 (0)

Parity, n (%)

 1

6 (50.0)

7 (58.3)

7 (53.8)

 2

5 (41.7)

5 (41.7)

3 (23.1)

 3

0 (0)

0 (0)

3 (23.1)

 4

1 (8.3)

0 (0)

0 (0)

Number of children (including this birth), n (%)

 1

6 (50)

7 (58.3)

7 (53.8)

 2

4 (33.3)

5 (41.7)

3 (23.1)

 3

1 (8.3)

0 (0)

3 (23.1)

 > 3

1 (8.3)

0 (0)

0 (0)

Delivery method of last childbirth, n (%)

 Vaginal

8 (66.7)

7 (58.3)

8 (61.5)

 Cesarean

4 (33.3)

5 (41.7)

5 (38.5)

Current breast symptom*, n (%)

 None

0 (0)

0 (0)

0 (0)

 Pain

11 (91.7)

10 (83.3)

9 (69.2)

 Redness

4 (33.3)

1 (8.3)

2 (15.4)

 Lump

12 (100)

12 (100)

11 (84.6)

 Secretion of nipple

0 (0)

0 (0)

0 (0)

 Warmth

1 (8.3)

1 (8.3)

2 (15.4)

 White spot

1 (8.3)

0 (0)

0 (0)

Current systemic symptom*, n (%)

 None

8 (66.7)

10 (83.3)

12 (92.3)

 Fever > 38.5 ˚C

0 (0)

0 (0)

0 (0)

 Flu-like illness

1 (8.3)

0 (0)

0 (0)

 General malaise

3 (25.0)

2 (16.7)

1 (7.7)

 Other

0 (0)

0 (0)

0 (0)

History of breast symptoms in previous breastfeeding experience, n (%)

5 (41.7)

4 (33.3)

5 (38.5)

Current breastfeeding type, n (%)

 Breast milk directly from the breast

0 (0)

2 (16.7)

2 (15.4)

 Pumped breast milk from a bottle

2 (16.7)

0 (0)

0 (0)

 Breast milk along with formula

10 (83.3)

10 (83.3)

11 (84.6)

Breastfeeding or pumping frequency, n (%)

 Every 2 h

1 (8.3)

1 (8.3)

1 (7.7)

 Every 3 h

3 (25.0)

2 (16.7)

4 (30.8)

 Every 4 h

7 (58.3)

8 (66.7)

8 (61.5)

 Every 5 h

0 (0)

1 (8.3)

0 (0)

 other

1 (8.3)

0 (0)

0 (0)

Self-management strategy*, n (%)

 None

0 (0)

0 (0)

2 (15.4)

 Correct latch-on techniques

3 (25.0)

3 (25.0)

4 (30.8)

 Breastfeed the baby more frequently

3 (25.0)

3 (25.0)

7 (53.8)

 Self-massage the breast

11 (91.7)

9 (75.0)

10 (76.9)

 Frequently express milk by hand or with a pump

4 (33.3)

7 (58.3)

7 (53.8)

 Relax and rest

6 (50.0)

5 (41.7)

7 (53.8)

 Use a supplemental nursing device

6 (50.0)

5 (41.7)

7 (53.8)

 Use warm/cold compresses

9 (75.0)

10 (83.3)

7 (53.8)

 Other

0 (0)

2 (16.7)

1 (7.7)

Treatment received for breast symptoms before enrolment into this study*, n (%)

 None

10 (83.3)

11 (91.7)

12 (92.3)

 Pain killer

1 (8.3)

1 (8.3)

1 (7.7)

 Antibiotics

1 (8.3)

0 (0)

1 (7.7)

 Antimycotics

0 (0)

0 (0)

0 (0)

 Steroids

0 (0)

0 (0)

0 (0)

 Herbal medicines

0 (0)

0 (0)

0 (0)

 Lubricants

0 (0)

0 (0)

0 (0)

 Other

1 (8.3)

0 (0)

0 (0)