IMPORTANCEMaternally derived antibodies are a key element of neonatal immunity. Understanding the dynamics of maternal antibody responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during pregnancy and subsequent transplacental antibody transfer can inform neonatal management as well as maternal vaccination strategies.OBJECTIVE To assess the association between maternal and neonatal SARS-CoV-2-specific antibody concentrations. DESIGN, SETTING, AND PARTICIPANTSThis cohort study took place at Pennsylvania Hospital in Philadelphia, Pennsylvania. A total of 1714 women delivered at the study site between April 9 and August 8, 2020. Maternal and cord blood sera were available for antibody measurement for 1471 mother/newborn dyads.EXPOSURES SARS-CoV-2. MAIN OUTCOMES AND MEASURESIgG and IgM antibodies to the receptor-binding domain of the SARS-CoV-2 spike protein were measured by enzyme-linked immunosorbent assay. Antibody concentrations and transplacental transfer ratios were analyzed in combination with demographic and clinical data. RESULTSThe study cohort consisted of 1714 parturient women, with median (interquartile range) age of 32 (28-35) years, of whom 450 (26.3%) identified as Black/non-Hispanic, 879 (51.3%) as White/non-Hispanic, 203 (11.8%) as Hispanic, 126 (7.3%) as Asian, and 56 (3.3%) as other race/ethnicity. Among 1471 mother/newborn dyads for which matched sera were available, SARS-CoV-2 IgG and/or IgM antibodies were detected in 83 of 1471 women (6%; 95% CI, 5%-7%) at the time of delivery, and IgG was detected in cord blood from 72 of 83 newborns (87%; 95% CI, 78%-93%). IgM was not detected in any cord blood specimen, and antibodies were not detected in any infant born to a seronegative mother. Eleven infants born to seropositive mothers were seronegative: 5 of 11 (45%) were born to mothers with IgM antibody only, and 6 of 11 (55%) were born to mothers with significantly lower IgG concentrations compared with those found among mothers of seropositive infants. Cord blood IgG concentrations were positively correlated with maternal IgG concentrations (r = 0.886; P < .001). Placental transfer ratios more than 1.0 were observed among women with asymptomatic SARS-CoV-2 infections as well as those with mild, moderate, and severe coronavirus disease 2019. Transfer ratios increased with increasing time between onset of maternal infection and delivery. CONCLUSIONS AND RELEVANCEIn this cohort study, maternal IgG antibodies to SARS-CoV-2 were transferred across the placenta after asymptomatic as well as symptomatic infection during pregnancy. Cord blood antibody concentrations correlated with maternal antibody concentrations and with duration between onset of infection and delivery. Our findings demonstrate the potential for maternally derived SARS-CoV-2 specific antibodies to provide neonatal protection from coronavirus disease 2019.

Strengths of this study included the timely nature of our findings as the COVID-19 pandemic ensues, death tolls reach record highs, and communities adopt methods of social distancing to flatten the disease curve. Our findings are applicable to the obstetrical population who, regardless of the COVID-19 pandemic, cannot safely avoid or delay contact with hospitals compared with other patient populations because pregnancy is finite. The limited number of patients in our study was a potential weakness. In addition, given that we only investigated obstetrical patients, our findings may not be generalizable to other populations within the medical community. In addition, our study is preliminary and ongoing; hence we do not have any data on pregnancy outcomes. Our results were similar to those reported in a Letter to the Editor in the New England Journal of Medicine published on April 13, 2020, reporting that 13.5% of patients during a 2-week time period in 1 institution were asymptomatic and positive for SARS-CoV-2 7 ; this finding was very similar to the asymptomatic SARS-CoV-2epositive rate in our population of 13% (21/161).Our results can be used as a guide to other L&D units in deciding whether all admitted obstetrical patients should be routinely tested for SARS-CoV-2, the virus responsible for COVID-19.

Background Preeclampsia and gestational hypertension are hypertensive disorders of pregnancy (HDP) that identify an increased risk of developing chronic hypertension and cardiovascular disease later in life. Postpartum follow‐up may facilitate early screening and treatment of cardiovascular risk factors. Our objective is to describe patterns of postpartum visits with primary care and women's health providers (eg, family medicine and obstetrics) among women with and without HDP in a nationally representative sample of commercially insured women. Methods and Results We conducted a retrospective cohort study using insurance claims from a US health insurance database to describe patterns in office visits in the 6 months after delivery. We identified 566 059 women with completed pregnancies between 2005 and 2014. At 6 months, 13% of women with normotensive pregnancies, 18% with HDP, and 23% with chronic hypertension had primary care visits ( P <0.0001 for comparing HDP and chronic hypertension groups with control participants). Only 58% of women with HDP had 6‐month follow‐up with any continuity provider compared with 47% of women without hypertension ( P <0.0001). In multivariable analysis, women with severe preeclampsia were 16% more likely to have postpartum continuity follow‐up (adjusted odds ratio, 1.16; 95% CI, 1.2–1.21). Factors associated with a lower likelihood of any follow‐up included age ≥30 years, Black race, Hispanic ethnicity, and having multiple gestations. Conclusions Rates of continuity care follow‐up after a pregnancy complicated by hypertension were low. This represents a substantial missed opportunity to provide cardiovascular risk screening and management to women at increased risk of future cardiovascular disease.

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