Pregnant women who are infected with SARS-CoV-2 are at an increased risk of adverse perinatal outcomes. With this study, we aimed to better understand the relationship between maternal infection and perinatal outcomes, especially preterm births, and the underlying medical and interventionist factors. This was a prospective observational study carried out in 78 centers (Spanish Obstetric Emergency Group) with a cohort of 1347 SARS-CoV-2 PCR-positive pregnant women registered consecutively between 26 February and 5 November 2020, and a concurrent sample of PCR-negative mothers. The patients’ information was collected from their medical records, and the association of SARS-CoV-2 and perinatal outcomes was evaluated by univariable and multivariate analyses. The data from 1347 SARS-CoV-2-positive pregnancies were compared with those from 1607 SARS-CoV-2-negative pregnancies. Differences were observed between both groups in premature rupture of membranes (15.5% vs. 11.1%, p < 0.001); venous thrombotic events (1.5% vs. 0.2%, p < 0.001); and severe pre-eclampsia incidence (40.6 vs. 15.6%, p = 0.001), which could have been overestimated in the infected cohort due to the shared analytical signs between this hypertensive disorder and COVID-19. In addition, more preterm deliveries were observed in infected patients (11.1% vs. 5.8%, p < 0.001) mainly due to an increase in iatrogenic preterm births. The prematurity in SARS-CoV-2-affected pregnancies results from a predisposition to end the pregnancy because of maternal disease (pneumonia and pre-eclampsia, with or without COVID-19 symptoms).

The COVID-19 pandemic has raised questions about the possible cross immunity resulting from common vaccination programs and SARS-CoV-2 infection. Therefore, the Spanish Obstetric Emergency group performed a multicenter prospective study on the vaccination status of Influenza and Tdap (diphtheria, tetanus and pertussis vaccine boost administered in adulthood) in consecutive cases of SARS-CoV-2 infection in a pregnancy cohort, in order to assess its possible association with the clinical presentation and severity of symptoms of SARS-CoV-2 infection, as well as to determine the factors that may affect vaccination adherence. A total of 1150 SARS-CoV-2 positive pregnant women from 78 Spanish hospitals were analyzed: 183 had not received either vaccine, 23 had been vaccinated for Influenza only, 529 for Tdap only and 415 received both vaccines. No association was observed between the vaccination status and the clinical presentation of SARS-CoV-2 infection and/or the severity of symptoms. However, a lower adherence to the administration of both vaccines was observed in the Latin-American subgroup. Based on the results above, we reinforce the importance of maternal vaccination programs in the actual pandemic. Health education campaigns should be specially targeted to groups less likely to participate in these programs, as well as for a future SARS-CoV-2 vaccination campaign.

Objective To evaluate the perinatal and maternal outcomes of pregnancies in SARS-CoV-2 infected women, comparing spontaneous and In Vitro Fertilization (IVF) pregnancies (with either own or donor oocytes). Design Multicentre, prospective, observational study. Setting 78 centres participating in the Spanish COVID19 Registry. Patients 1,347 SARS-CoV-2 positive pregnant women registered consecutively between February 26 th and November 5 th , 2020. Interventions Patient´s information was collected from their medical records, and multivariable regression analyses were performed, controlling for maternal age and the clinical presentation of infection. Main outcome measures Obstetrics and neonatal outcomes, pregnancy comorbidities, intensive care unit admission, mechanical ventilation need and medical conditions. Results The IVF group was composed of 74 (5.5%) women whereas the spontaneous group included 1,275 (94.5%) women. Operative delivery rate was high in all patients, especially in the IVF group, where C-section became the most frequent method of delivery (55.4%, compared to 26.1% of spontaneous). The reason for C-section was induction failure in 56.1% of IVF patients. IVF women had more gestational hypertensive disorders [16.2% vs 4.5% among spontaneous, adjusted Odds Ratio (aOR) 5.31, 95% Confidence Interval (CI) 2.45-10.93) irrespective of oocyte origin. The higher rate of ICU admittance observed in the IVF group (8.1% vs 2.4% spontaneous) was attributed to pre-eclampsia (aOR 11.82, 95% CI 5.25-25.87), not to the type of conception, Conclusions High rate of operative delivery has been observed in SARS-CoV-2 infected women, especially in IVF pregnancies; method of conception does not affect foetal or maternal outcomes, except for pre-eclampsia.

Research Question: Is there an association between SARS-CoV-2 infection and firsttrimester miscarriage?Design: Multicenter prospective study of a cohort of first-trimester miscarriages registered consecutively by seven Spanish hospitals, where universal PCR screening for SARS-CoV-2 infection was implemented for both, miscarriages and deliveries. The incidence of SARS-CoV-2 infection among first-trimester miscarriages was compared to the one registered in women at admission on delivery ward within the same timeframe using a mixed-effects Poisson regression analysis, considering hospital as random effect. On the other hand, the characteristics of SARS-CoV-2 positive and negative patients who miscarried were compared through two-sided univariable analyses.Results: 301 miscarriages were registered, 11 (3.7%) SARS-CoV-2 infected and 290 non-infected. No differences in terms of SARS-CoV-2 infection incidence were observed between miscarriages and deliveries [1,936 deliveries were registered at the same time of miscarriages and 44 (2.3%) were SARS-CoV-2 infected] (p= 0.233). Regarding the differences observed between SARS-CoV-2 positive and negative patient miscarriages, more inevitable miscarriages occurred in the group of infected women (36.4% vs 16.5% in non-infected, p= 0.004), as well as more surgical management of miscarriages (27.3% vs 8.2% in non-infected, p= 0.036), which is probably in line with the greater number of inevitable miscarriages observed in this group.Conclusions: No association between SARS-CoV-2 infection and risk of first-trimester miscarriage has been observed; however, the type of miscarriage seems to be different between SARS-CoV-2 positive and negative women, with inevitable miscarriage being more frequent among infected women.

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