COVID-19 and Pregnancy: A Dangerous Mix for Bone Turnover and Metabolism Biomarkers in Placenta and Colostrum.

Background: In pregnant women, COVID-19 can alter the metabolic environment, cell metabolism, and oxygen supply of trophoblastic cells and, therefore, have a negative influence on essential mechanisms of fetal development. The purpose of this study was to investigate, for the first time, the effects of COVID-19 infection during pregnancy with regard to the bone turnover and endocrine function of several metabolic biomarkers in colostrum and placenta. Methods: One hundred and twenty-four pregnant mothers were recruited from three hospitals between June 2020 and August 2021 and assigned to two groups: Control group and COVID-19 group. Metabolism biomarkers were addressed in placental tissue and colostrum. Results: Lipocalin-2 and resistin levels were higher in the placenta, revealing an underlying pro-inflammatory status in the gestation period for mothers suffering from COVID-19; a decrease in GLP-1 and leptin was also observed in this group. As for adiponectin, resistin, and insulin, their concentrations showed an increase; a decrease in GLP-1, leptin, and PYY was also reported in the colostrum of mothers suffering from COVID-19 compared with the control group. Conclusions: As for bone turnover, placental samples from mothers with COVID-19 showed lower levels of OPG, while DKK-1 increased compared with the control group. Colostrum samples showed higher levels of OPG, SOST, and PTH in the COVID-19 group, a fact that could have noteworthy implications for energy metabolism, fetal skeletal development, and postnatal bone density and mineralization. Further research is needed to explain the pathogenic mechanism of COVID-19 that may affect pregnancy, so as to assess the short-term and long-term outcomes in infants' health.