key: cord-0837491-efn58qca
authors: Wood, Rachel; Sinnott, Colleen; Goldfarb, Ilona; Clapp, Mark; McElrath, Thomas; Little, Sarah
title: Preterm Birth During the Coronavirus Disease 2019 (COVID-19) Pandemic in a Large Hospital System in the United States
date: 2021-02-03
journal: Obstet Gynecol
DOI: 10.1097/aog.0000000000004237
sha: 862827beffa95404bd7f7ce9e2eb2479c0f9f8ad
doc_id: 837491
cord_uid: efn58qca

The preterm birth rate was unchanged in a metropolitan U.S. hospital system during the peak of the coronavirus disease 2019 (COVID-19) pandemic compared with the prior year.

D enmark and Ireland have reported drastic reductions in the rate of preterm birth during the coronavirus disease 2019 (COVID-19) global pandemic, 1,2 though this was not found in the United Kingdom. 3 These findings have led to widespread speculation, both in the academic and lay press, that the acts of social isolation and quarantine may lead to a reduction in the incidence of preterm birth. [1] [2] [3] [4] We investigated whether our hospital system in the United States had any change in the preterm delivery rate during the peak COVID-19 pandemic era when compared with the pre-COVID-19 era.

We compared singleton live births at 20 weeks of gestation or greater during the peak COVID-19 pandemic era (April through July of 2020, during the statewide recommended "stay-at-home" order in Massachusetts) with those in a pre-COVID-19 era (April through July 2019). We included four hospitals within our hospital system, all with level 3 or 4 neonatal intensive care units (two large academic teaching hospitals and two community-based hospitals), excluding women who were already at 37 weeks of gestation or greater at the start of the time period. Data were abstracted from the electronic medical record. Race and ethnicity were selfreported in electronic medical record patient demographics. We looked at the overall gestational age distribution during the peak of the COVID-19 pandemic era and the pre-COVID-19 era, as well as the rate of preterm birth using various thresholds. This study was approved by the Mass General Brigham Institutional Review Board.

Our cohort included 9,356 deliveries: 4,644 in the pre-COVID-19 pandemic era and 4,712 during the peak COVID-19 pandemic era. The distribution of gestational ages was identical in the two eras (median gestational age at delivery 39 2/7 weeks in both). There was no difference in the overall rate of preterm birth at less than 37 weeks of gestation (7.4% vs 7.9%; P5.4), nor any differences in the rate of delivery at less than 34, less than 32, or less than 28 weeks. There was no difference in spontaneous compared with iatrogenic preterm birth (56.1% of preterm deliveries in 2019 were spontaneous vs 54.6% in 2020; P5.7). In a post hoc power calculation, we had 80% power to detect a 20% reduction in the overall rate of preterm birth. In the peak COVID-19 pandemic era, 158 (3.4%) deliveries were to women who had severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection confirmed by polymerase chain reaction test at any time. Infection was more common in women who were Black (6.7% vs 3.0%; P,.01), See related editorial on page 399. Hispanic (11.3% vs 1.8%; P,.01), and publicly insured (10.7% vs 1.4%; P,.01); however, there were no reductions in preterm birth in any demographic subgroup. Results were similar when excluding the 158 women with polymerase chain reaction testconfirmed SARS-CoV-2 infection.

We report no reduction in the preterm birth rate at our hospital system in the United States during the COVID-19 pandemic. We had adequate power to detect up to a 20% reduction in preterm birth, far less than the 70-90% reduction seen in Denmark and Ireland. 1, 2 There were no differences in transfer or referral patterns for preterm delivery in the two time periods, with more than 90% of transfers occurring from within our hospital system in both. There were no differences in preterm birth type (spontaneous vs iatrogenic), indicating that changes in prenatal care delivery during the pandemic did not alter iatrogenic preterm birth rates. The rate of preterm birth and SARS-CoV-2 infection in the United States and in our hospital system are significantly higher than the rates in the previous international studies, which may in part account for the disparate findings. Our cohort showed Black, Hispanic, and publicly insured women to have higher rates of SARS-CoV-2 infection, consistent with previous findings 5 ; however, we did not find any reduction in preterm birth overall or in any demographic groups. Our study findings do not support the theory that quarantine or health care delivery changes during the COVID-19 pandemic decrease rates of preterm birth (Table 1) .

Danish premature birth rates during the COVID-19 lockdown

Unprecedented reduction in births of very low birthweight (VLBW) and extremely low birthweight (ELBW) infants during the COVID-19 lockdown in Ireland: a 'natural experiment' allowing analysis of data from the prior two decades

Change in the incidence of stillbirth and preterm delivery during the COVID-19 pandemic

During coronavirus lockdowns, some doctors wondered: where are the preemies? Accessed

Influence of race and ethnicity on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection rates and clinical outcomes in pregnancy

Received in revised form

) and During the Peak of the Pandemic

Pre-COVID-19 (n54,644) Peak COVID-19 (n54

COVID-19, coronavirus disease 2019. Data are median (interquartile range) or n/N (%) unless otherwise specified

* P derived from Wilcoxon rank-sum (continuous) or x 2 (categorical) test