Haan, mostly safe hota hai unless doctor ne explicitly mana kiya ho. But shuruat ke months sensitive hote hain, isliye avoid karna ya gently rehna better option hai.
Between work travel and fatigue, we actually skipped it, but my gynac said it's completely safe unless there is spotting. Just keep your gynac in loop.
For us, after a long treatment journey, we were extremely careful and avoided it completely in the first trimester. If you have any history of spotting, please protect your peace of mind and consult your doctor.
As per my pregnancy tracker, early sex is perfectly safe because the baby is protected by the amniotic sac. But make sure there's no history of complications or doctor-advised bed rest!