Quercetin is active, and therefore whilst I don't know of any bad problems taking it in pregnancy, I'd be cautious, especially with higher doses:
https://www.researchgate.net/p…_homeostasis_at_adulthood
The "standard advice" is:
Risks. Kidney damage may result from high doses. If you are pregnant or breastfeeding, do not take quercetin as a supplement. You may get too much, especially since quercetin is in so many foods.
As always, don't accept medical advice from an internet forum. The above is posted as some internet research.