Table 1 Characteristics of the study subjects meeting the inclusion criteria. Data are mean [range] or % (n/N). ^ap < 0.001 when compared to females

Maternal age at delivery (years)

34 [23–43]

34 [18–43]

Maternal pre-pregnancy body mass index (kg/m²)

25.2 [17.5–43.6]

25.3 [17.4–43.6]

Race (%)

 Asian

25 (22/87)

18 (16/90)

 Black or African American

9 (8/87)

13 (12/90)

 White

62 (54/87)

65 (58/90)

 Other

4 (3/87)

4 (4/90)

Gestational age at first ultrasound visit (weeks)

16 [15-17]

16 [12-17]

Cesarean delivery (%)

36 (31/87)

41 (37/90)

Gestational age at delivery (weeks)

38 [30–41]

38 [31–40]

Birth weight (g)

3159 [1390–4390]

3422 [1410–4630]^a