SARS-CoV-2 infection in early first-trimester miscarriages: a prospective observational study.

RESEARCH QUESTION: Is there an association between SARS-CoV-2 infection and first-trimester miscarriage? DESIGN: This multicentre prospective study included a cohort of women with first-trimester miscarriages registered consecutively by seven Spanish hospitals where universal PCR screening for SARS-CoV-2 infection was implemented with both miscarriages and deliveries. The incidence of SARS-CoV-2 infection among women with first-trimester miscarriages was compared with the rate registered in women on admission to the delivery ward within the same time frame using a mixed-effects Poisson regression analysis, considering 'hospital' as random effect. The characteristics of SARS-CoV-2 positive and negative patients who miscarried were compared through two-sided univariable analyses. RESULTS: A total of 301 miscarriages were registered, 11 (3.7%) to SARS-CoV-2 infected and 290 to non-infected women. In the same time frame as the miscarriages, 1936 deliveries were registered, 44 [2.3%] of them were SARS-CoV-2 infected. No differences in terms of SARS-CoV-2 infection incidence were observed between infected miscarriages and infected deliveries (P = 0.233). Regarding the differences observed between miscarriages in SARS-CoV-2 positive and negative women, more inevitable miscarriages occurred in the group of infected women (36.4% versus 16.5% in non-infected women; P = 0.004), and there was greater surgical management of miscarriages (27.3% versus 8.2% in non-infected women; P = 0.036), 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 was observed; however, the type of miscarriage seems to differ between SARS-CoV-2 positive and negative women, with inevitable miscarriage being more frequent among infected women.

The association between SARS-CoV-2 infection and preterm delivery: a prospective study with a multivariable analysis.

BACKGROUND: To determine whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, the cause of COVID-19 disease) exposure in pregnancy, compared to non-exposure, is associated with infection-related obstetric morbidity. METHODS: We conducted a multicentre prospective study in pregnancy based on a universal antenatal screening program for SARS-CoV-2 infection. Throughout Spain 45 hospitals tested all women at admission on delivery ward using polymerase-chain-reaction (PCR) for COVID-19 since late March 2020. The cohort of positive mothers and the concurrent sample of negative mothers was followed up until 6-weeks post-partum. Multivariable logistic regression analysis, adjusting for known confounding variables, determined the adjusted odds ratio (aOR) with 95% confidence intervals (95% CI) of the association of SARS-CoV-2 infection and obstetric outcomes. MAIN OUTCOME MEASURES: Preterm delivery (primary), premature rupture of membranes and neonatal intensive care unit admissions. RESULTS: Among 1009 screened pregnancies, 246 were SARS-CoV-2 positive. Compared to negative mothers (763 cases), SARS-CoV-2 infection increased the odds of preterm birth (34 vs 51, 13.8% vs 6.7%, aOR 2.12, 95% CI 1.32-3.36, p = 0.002); iatrogenic preterm delivery was more frequent in infected women (4.9% vs 1.3%, p = 0.001), while the occurrence of spontaneous preterm deliveries was statistically similar (6.1% vs 4.7%). An increased risk of premature rupture of membranes at term (39 vs 75, 15.8% vs 9.8%, aOR 1.70, 95% CI 1.11-2.57, p = 0.013) and neonatal intensive care unit admissions (23 vs 18, 9.3% vs 2.4%, aOR 4.62, 95% CI 2.43-8.94, p <  0.001) was also observed in positive mothers. CONCLUSION: This prospective multicentre study demonstrated that pregnant women infected with SARS-CoV-2 have more infection-related obstetric morbidity. This hypothesis merits evaluation of a causal association in further research.