It is best to speak with your doctor before taking dandelion during pregnancy. No formal safety studies around this have been performed with women who are pregnant and it is, therefore, advised to stay away from dandelion greens during pregnancy.

Pregnancy and Coronavirus (COVID-19)
What effect does coronavirus have on pregnant women? Pregnant women do not appear to be more susceptible to the consequences of coronavirus than the general population and there is no evidence that the virus can pass to a baby during pregnancy