Table 1 Baseline maternal characteristics and gestational weight gain of the pre-COVID-19 cohort and cohorts with pandemic exposure

Maternal age at conception

 < 0.001

 < 20 years

158 (1.1%)

67 (1.0%)

62 (0.9%)

 20–24.9 years

1,022 (7.0%)

418 (6.1%)

386 (5.8%)

 25–34.9 years

9,085 (62.0%)

4,322 (62.7%)

3,980 (59.8%)

 35–39.9 years

3,857 (26.3%)

1,803 (26.2%)

1,924 (28.9%)

 40 years and over

541 (3.7%)

280 (4.1%)

302 (4.5%)

Pre-pregnancy BMI category^a

 < 0.001

 Underweight

637 (4.3%)

267 (3.9%)

209 (3.1%)

 Healthy weight

7.453 (50.8%)

3,462 (50.3%)

3,100 (46.6%)

 Overweight

4,006 (27.3%)

1,915 (27.8%)

1,971 (29.6%)

 Obese

2,567 (17.5%)

1,246 (18.1%)

1,374 (20.7%)

Ethnicity

 < 0.001

 South Asian

4,021 (29.9%)

2,087 (30.9%)

2,153 (33.0%)

 Middle Eastern

5,088 (37.3%)

2,396 (35.4%)

1,949 (29.8%)

 Caucasian

2,249 (16.7%)

1,274 (18.8%)

1,397 (21.4%)

 East and Southeast Asian

1,963 (14.6%)

899 (13.3%)

896 (13.7%)

 Aboriginal and Torres Strait Islander

205 (1.5%)

109 (1.6%)

140 (2.1%)

Socioeconomic disadvantage: SEIFA quintile^b

0.001

 Q1 (most disadvantaged)

2,465 (23.5%)

1,122 (22.3%)

1,024 (21.5%)

 Q2

2,785 (26.6%)

1,397 (27.7%)

1,350 (28.4%)

 Q3

1,820 (17.4%)

823 (16.3%)

814 (17.1%)

 Q4

1,465 (14.0%)

797 (15.8%)

745 (15.7%)

 Q5 (least disadvantaged)

1,936 (18.5%)

901 (17.9%)

827 (17.4%)

Smoking in pregnancy

699 (4.8%)

314 (4.6%)

276 (4.2%)

0.20

Nulliparity

6,627 (45.2%)

3,013 (43.7%)

2,649 (39.8%)

 < 0.001

Prior history of gestational diabetes

962 (6.6%)

511 (7.4%)

565 (8.5%)

 < 0.001

First degree family member or sister with diabetes

5,769 (39.7%)

2,770 (40.5%)

2,904 (44.2%)

 < 0.001

Polycystic ovarian syndrome

917 (6.3%)

492 (7.1%)

466 (7.0%)

0.02

History of mental health conditions

1,814 (12.4%)

1,006 (14.6%)

952 (14.3%)

 < 0.001

COVID-19 infection in pregnancy

0

8 (0.1%)

111 (1.7%)

 < 0.001

Rate of 1^st and 2^nd trimester gestational weight gain (kg/week)

0.59 ± 0.58

0.64 ± 0.61

0.64 ± 0.62

 < 0.001

Excessive 2^nd trimester gestational weight gain by IOM^c

7,015 (64.3%)

3,658 (66.0%)

3,577 (66.6%)

0.009