11332767 True, having sex while being pregnant is perfectly safe, though we can assume that as much as they love Spike, Cadance and Luna wouldn't necessarily be very active or in the mood for sex during their pregnancy. As for magic protecting the sperm, again that is also possible! However, two babies were enough for an alliance, so it would be pure jealousy on Celestia's part if she decided to orchestrate and ensure becoming pregnant with Spike's child, not exactly a good enough reason.
Awww. The butts and not the wombs? No babies in the baby makers then.
11092942
Unfortunately not!
It’s not dangerous to bang while pregnant. Also, Celestia’s problem should be solvable with magic to protect the sperm cells.
11332767
True, having sex while being pregnant is perfectly safe, though we can assume that as much as they love Spike, Cadance and Luna wouldn't necessarily be very active or in the mood for sex during their pregnancy. As for magic protecting the sperm, again that is also possible! However, two babies were enough for an alliance, so it would be pure jealousy on Celestia's part if she decided to orchestrate and ensure becoming pregnant with Spike's child, not exactly a good enough reason.