Table 6.
Summary of literature to date evaluating PTB rates during the COVID-19 pandemic
| Study, year | Country | Pre–COVID-19 | During COVID-19 | Spont | Singletons | Method | Results | Conclusions |
|---|---|---|---|---|---|---|---|---|
| Time frame(PTB/total) | Time frame(PTB/total) | |||||||
| Been et al,4 2020a | The Netherlands | March 9, 2010–July 16, 2019; X/1,010,152 |
March 9, 2020–July 16, 2020; X/56,720 |
No | Yes | Difference in difference approach. | Unadj OR, 0.84 (0.73–0.97) | Reductions in PTB, limited to neighborhoods of higher socioeconomic status. |
| Berghella et al,1 2020 | United States | March 1–July 31, 2019; 115/911; spontaneous: 59/911 |
March 1, 2020–July 31, 2020; 118/1197; spontaneous: 57/1197 |
Yes | No | Multivariate logistic regression. Adjusted for race or ethnicity. | Adj OR, 0.75 (0.57–0.99); spontaneous: adj OR, 0.75 (0.52–1.10) |
25% decrease in odds of PTB. No statistically significant difference in spontaneous PTB. |
| Handley et al,9 2020 | United States | March 1, 2018–June 30, 2019; 617/5907; spontaneous: 315/5907 |
March 1, 2020–June 30, 2020; 283/3007; spontaneous: 135/3007 |
Yes | Yes | Marginal effects models. Adjusted for birth month, age, parity, BMI, race or ethnicity, marital status, smoking and insurance status. Stratified by race. | Adj RD, −1.1 (−2.4 to 0.2); spontaneous: adj RD, −0.8 (−1.8 to 0.2) |
No significant decrease in overall PTB. Significant decrease in spontaneous PTB in white women only. [adjusted RD, −1.4 (−2.8 to −0.1)]. |
| Hedermann et al,2 2021 | Denmark | March 12, 2015–April 14, 2019; 1317/26,018 |
March 12, 2020–April 14, 2020; 249/5162 |
No | Yes | Prevalence proportion study. | Unadj OR, 0.95b | No significant decrease in overall PTB. Decrease in births at <28 wk (unadjusted OR, 0.09 [0.01–0.40]). |
| KC et al,10 2020 | Nepal | Jan. 1–March 20, 2020; 2125/13,189 |
March 21, 2020–May 30, 2020; 1342/7165 |
No | Yes | Adjusted for complication during admission, ethnicity, and maternal age. | Adj OR, 1.30 (1.20–1.40); unadju OR, 1.198 (1.113–1.125) |
Significant increase in overall PTB. Significant decline in births at a hospital. |
| Khalil et al,11 2020 | United Kingdom | Oct. 1, 2019–Jan. 31, 2020; 113/1655 |
Feb. 1, 2020–June 14, 2020; 127/1692 |
No | No | Mann-Whitney and Fisher's exact tests. | Unadj RD, −0.68 (−2.43 to 1.07) | No significant decrease in overall PTB. |
| Philip et al,3 2020 | Ireland | Jan. 1, 2001–April 30, 2019; 210/29,324 VLBW |
Jan. 1, 2020–April 30, 2020; 3/1381 VLBW |
No | No | Poisson regression analysis. | Rate ratio,c 3.77 (1.21–11.75) | Significant 73% decrease in the incidence of VLBW infants (used as a surrogate of PTB and gestational age). |
Adj, adjusted; COVID-19, coronavirus disease 2019; OR, odds ratio; PTB, preterm birth (<37 weeks’ gestation); RD, risk difference; spont, spontaneous; unadj, unadjusted; VLBW, very low birthweight.
a
Referring to a primary analysis using March 9, 2020, regulation cutoffs with 4-month follow-up. Crude counts of PTBs before and after March 9, 2020, are not available in this manuscript;
b
No confidence interval because OR was calculated by hand;
c
VLBW using 2020 as referent.
Lemon. Differential decreases in spontaneous preterm birth during coronavirus disease 2019. Am J Obstet Gynecol MFM 2021.