Table 4.
Multivariable logistic regression model: association between overall preterm births and COVID-19 lockdown (adjusted for mother’s demographic and clinical characteristics)
| Variables | Complete lockdown compared to the same time period in 20191 | Overall lockdown compared to the same time period in 20192 | Overall lockdown compared to the same time period in 2015 to 20193 | |||
|---|---|---|---|---|---|---|
| OR (95% CI) (adjusted) | P-value | OR (95% CI) (adjusted) | P-value | OR (95% CI) (adjusted) | P-value | |
| Year of Birth 2020 vs. (ref = 2019 or 2019 to 2015) | 1.07 (0.98, 1.18) | 0.13 | 1.08 (1.01, 1.15) | 0.03 | 1.11 (1.05, 1.18) | <0.001 |
| Maternal age | 1.01 (1.00, 1.02) | 0.01 | 1.01 (1.00, 1.01) | 0.03 | 1.01 (1.01, 1.01) | <0.001 |
| Nulliparous (ref = 0) | 1.15 (1.04, 1.27) | 0.01 | 1.05 (0.97, 1.12) | 0.22 | Data not available | |
| Pregnancy-induced hypertension (ref = 0) | 2.84 (2.49, 3.23) | <0.001 | 2.72 (2.48, 2.99) | <0.001 | 2.94 (2.79, 3.10) | <0.001 |
| Delivery method C-section (ref = false) | 2.13 (1.75, 2.58) | <0.001 | 2.14 (1.86, 2.45) | <0.001 | Data not available | |
| Maternal steroids administered (ref = false) | 56.57 (46.83, 68.32) | <0.001 | 67.47 (58.56, 77.73) | <0.001 | 58.75 (54.73, 63.06) | <0.001 |
| Mode of delivery (ref = false) | 1.44 (1.19, 1.75) | <0.001 | 1.37 (1.19, 1.57) | <0.001 | 0.73 (0.71, 0.76) | <0.001 |
| Material deprivation quintile 2 vs. 1 (ref = 1, lease deprived) | 0.93 (0.80, 1.08) | 0.32 | 1.03 (0.92, 1.14) | 0.65 | 1.03 (0.92, 1.14) | 0.62 |
| Material deprivation quintile 3 vs. 1 (ref = 1, lease deprived) | 0.97 (0.83, 1.13) | 0.67 | 1.05 (0.94, 1.17) | 0.37 | 1.05 (0.94, 1.17) | 0.41 |
| Material deprivation quintile 4 vs. 1(ref = 1, lease deprived) | 1.12 (0.96, 1.30) | 0.14 | 1.18 (1.06, 1.31) | <0.001 | 1.19 (1.07, 1.32) | <0.001 |
| Material deprivation quintile 5 vs. 1 (ref = 1, lease deprived) | 1.16 (1.00, 1.34) | 0.04 | 1.20 (1.08, 1.33) | <0.001 | 1.11 (1.02, 1.21) | 0.02 |
This includes for all live births and singleton births only, outcome variable − overall preterm (0/1). 1= Any preterm, 0 = term, and post term. The event = 1 (= any preterm) and independent variable is year of birth, maternal age, nulliparous, pregnancy-induced hypertension, delivery method C-section, maternal steroids administered, mode of delivery, material deprivation (1 to 5, 1 = least deprived, 5-most deprived).
1Complete lockdown vs. the same calendar period of the previous year = 15th March to 31st July 2020 vs. 15th March to 31st July 2019.
2Overall lockdown vs. the same calendar period of the previous year = 15th March to 31st December 2020 vs. 15th March to 31st December 2019.
3Overall lockdown vs. the same calendar period of the previous 5 years = 15th March to 31st December 2020 vs. 15th March to 31st December 2015 to 2019