PGF and COVID-19: However, it must be noted that the analytical signs (inflammatory, hypertensive and biochemical alterations) of COVID-19 could be interpreted as alterations due to pre-eclampsia instead and, to correctly classify these cases (and distinguish between moderate and severe pre-eclampsia), it would be necessary to measure angiogenic factors in the blood (sFlt-1/PlGF) and perform an echo-Doppler of the uterine arteries [21].