Covid-19 seroprevalence in a group of pregnant women compared to a group of non-pregnant women

Pregnant women are an interesting population to study in the context of the current Coronavirus Disease 2019 (COVID-19); studies are still controversial in concluding if pregnancy is a protective condition or a risk factor for a more severe form of the illness. We estimated rate of positive serology for SARS-CoV-2 in a population of healthy pregnant women, compared to a population of non-pregnant women of the same age and geographic area. We also made a comparison between the two groups in terms of previous symptoms and lifestyle. This is a transversal study including pregnant women, above 18 weeks of gestation, aged between 18 and 40 years. The control group consisted of 588 non pregnant women from the same area and the same age group. A total of 344 pregnant women and 588 non pregnant women were recruited. The rate of positive serology for SARS-CoV-2 was significantly lower in the pregnant group: 9/344 (2.6%) versus 75/588 (12.8%) in the non-pregnant group (p < 0.0001). The two groups were similar in terms of occupation and in the self-re-ported habit to leave the house during the lockdown. Our hypothesis to explain this result is that pregnant women might have adopted a more prudential lifestyle, due to their special condition, which may have led them to behave with more caution, i.e., concerning the responsibility of wearing all the disposable personal protective equipment, and keeping the recommended 6 feet distance from other people.