The pandemic, COVID-19 disease and perinatal health

Adverse effects of COVID-19 on perinatal health have been documented, however there is a lack of research that separates individual disease from other changing risks during the pandemic period. We linked California statewide birth and hospital discharge data for 2019-2020, and compared health indicators among 3 groups of pregnancies: [a] 2020 delivery with COVID-19, [b] 2020 delivery with no documented COVID-19, and [c] 2019 pre-pandemic delivery. We aimed to quantify the links between COVID-19 and perinatal health, separating individual COVID-19 disease (a vs b) from the pandemic period (b vs c). We examined the following health indicators: preterm birth, hypertensive disorders of pregnancy, gestational diabetes mellitus and severe maternal morbidity. We applied model based standardization to estimate "average effect of treatment on the treated" risk differences (RD), and adjusted for individual and community-level confounders. Among pregnancies in 2020, those with COVID-19 disease had higher burdens of preterm birth (RD[95% confidence interval (CI)]=2.8%[2.1,3.5]), hypertension (RD[95% CI]=3.3%[2.4,4.1]), and severe maternal morbidity (RD[95% CI]=2.3%[1.9,2.7]) compared with pregnancies without COVID-19 (a vs b) adjusted for confounders. Pregnancies in 2020 without COVID-19 had a lower burden of preterm birth (RD[95% CI]=-0.4%[-0.6,-0.3]), particularly spontaneous preterm, and a higher burden of hypertension (RD[95% CI]=1.0%[0.9,1.2]) and diabetes RD[95%CI]=0.9%[0.8,1.1] compared with pregnancies in 2019 (b vs c) adjusted for confounders. Protective associations of the pandemic period for spontaneous preterm birth may be explained by socioenvironmental and behavioral modifications, while increased maternal conditions may be due to stress and other behavioral changes. To our knowledge, our study is the first to distinguish between individual COVID-19 disease and the pandemic period in connection with perinatal outcomes. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This research was supported by the National Institutes of Health (R01HD098138, Jennifer Ahern, Principal Investigator), and (R00ES033274 Dana Goin, Principal Investigator). The findings and conclusions are those of the authors and do not necessarily represent the official position of the National Institutes of Health. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This study was reviewed and approved by the California Health and Human Services Agency and University of California, Berkeley Committees for the Protection of Human Subjects. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Birth and hospital discharge data are available upon request for research projects from the California Department of Public Health, Center for Health Statistics and Informatics, and from the California Department of Health Care Access and Information.