SARS-CoV-2 Seroconversion and Pregnancy Outcomes in a Population of Pregnant Women Recruited in Milan, Italy, between April 2020 and October 2020

Abstract

The possible link between SARS-CoV-2 infection and adverse pregnancy outcomes has so far demonstrated heterogeneous results in terms of maternal, fetal, and neonatal complications. We aim to investigate the correlation between SARS-CoV-2 seroconversion and/or neutralization titer and pregnancy outcomes. We analyzed a population of 528 pregnant women followed up from the first trimester of gestation until delivery. For each woman, we collected a first blood sample between 11 and 13 weeks of gestation and a second sample in the perinatal period (between peripartum and puerperium) to assess the presence of SARS-CoV-2 antibodies and/or microneutralization titer (MN titer). Data on pregnancy outcomes (gestational age at delivery, preterm birth before 34 weeks, hypertensive disorders, gestational diabetes, and abnormal fetal growth) were collected. We observed that serologic status per se is not associated with major pregnancy complications. On the contrary, the MN titer was associated with increased odds of gestational diabetes. Although we mainly reported asymptomatic SARS-CoV-2 infections and the absence of severe maternal and neonatal adverse outcomes, SARS-CoV-2 infection might challenge the maternal immune system and explain the moderate increase in adverse outcome odds.

Maternal COVID-19 Serological Changes—Comparison between Seroconversion Rate in First and Third Trimesters of Pregnancy and Subsequent Obstetric Complications: A Cohort Study

“…In a retrospective study evaluating 882 positive pregnant women with rRT-PCR SARS-CoV2, including 85 women diagnosed in the first trimester, it was reported that gestational age at the time of infection was the best predictor for gestational age at delivery [27]. To the best of our knowledge, there is only one study that has been conducted to assess SARS-CoV2 serology during both the first and third trimesters while examining the potential association between the presence of antibodies and pregnancy outcomes [28]. In this study, which involved 528 singleton pregnant women, the authors carried out serological assessments during the initial 11-13-week screening visit and again upon the admission for delivery.…”

Pyroptosis: A Promising Mechanism Linking SARS-CoV-2 Infection to Adverse Pregnancy Outcomes

“…The study included 231 pregnant women who were recruited at the Fetal Medicine Unit of the Policlinico Hospital in Milan (Italy), between April and September 2020. The study is a nested case-control study embedded in a larger investigation that has been previously described [56].…”

“…Data on pregnancy outcomes and neonatal parameters were collected from the hospital medical records if delivery occurred at our hospital, or by telephone interview otherwise. The diagnosis of adverse pregnancy outcomes (i.e., pre-eclampsia, gestational diabetes mellitus, abnormal growth, and delivery < 34 weeks) was made according to guidelines and as reported in [56].…”

“…Immunoglobulin (Ig)G, IgM, and IgA quantification in human plasma samples was performed using an in-house ELISA RBD assay, as described in [56]. Briefly, 96-well ELISA plate coating was performed using 1 µg/mL of purified recombinant Wuhan/Ancestral SARS-CoV-2 Spike-RBD protein (Arg319-Phe541) (Sino Biological, Beijing, China).…”

“…The Micro Neutralization (MN) assay performed in this study has been extensively described in previous publications [56,57]. Briefly, plasma samples were subjected to 2-fold serial dilutions in DMEM with 2% FBS (from 1:10 to 1:320, in duplicate) and added to two different 96-well plates.…”