Table 1 Comparison of demographics, hair variables, and medication use among the three groups of pregnant women

 Age, years, mean (SD)

33.8 (4.3)

31.6 (6.0)

33.3 (5.5)

0.240^k

 BMI, kg/m², median (IQR, n)

  Pregnant

28.8 (25.4–32.5, 31)

28.2 (25.0–34.2, 25)

27.8 (24.7–32.2, 41)

0.716^l

  Pre-Pregnancy

24.6 (20.9–27.2, 31)

25.8 (22.8–31.3, 25)

24.8 (21.8–29.4, 42)

0.554^l

 PSS Score, mean (SD, n)

12 (5–26)

15 (7–9)

15 (6–23)

0.210^k

 Gestational age, weeks, median (IQR, n)

39.6 (39.0–40.9, 30)

39.1 (37.6–40.6, 28)

39.1 (38.1–40.3, 51)

0.155^l

 Birth weight, kg, median (IQR, n)

3.41 (3.11–3.65, 31)

3.37 (2.76–3.64, 30)

3.31 (2.89–3.63, 52)

0.701^l

 Sample age, days^b, mean (SD)

334 (82)

325 (93)

315 (103)

0.661^k

 # Washes per week, median (IQR, n)

3.5 (2.5–4.5, 31)

3.0 (2.5–5.5, 24)

4.0 (3–6.6, 42)

0.141^l

 # Days since last washed, median (IQR, n)

1 (0–2, 29)

1 (0–1, 23)

1 (0–1, 37)

0.375^l

 Chemical treatment^c, n (%)

19 (61.3)

17 (of 26, 65.4)

25 (of 47, 53.2)

0.563^m

 Inhaled corticosteroid use^d, Yes/No

No

No

Yes

–

 Oral corticosteroid use^e, n (%)

0 (0)

3 (9.7)

4 (7.1)

0.280^m

 Intranasal corticosteroid use^f, n (%)

3 (9.7)^h

2 (6.5)^h

16 (28.6)

0.014 ^m

 Topical corticosteroid use^f, n (%)

5 (16.1)

2 (6.4)

7 (12.5)

0.343^m

 Other steroid hormone use (e.g., progesterone)^f, n (%)

3 (9.7)

4 (12.9)

6 (10.7)

0.867^m

 Beta-agonist^f,g, n (%)

2 (6.4)ⁱ

24 (77.4)^j

54 (96.4)

<0.0001 ^m

 Number of other classes of medications used^f, median (IQR)

2 (1–3)

2 (0–4)

2 (1–3)

0.650^l