Unless your doctor has specifically told you to avoid it due to some complication like low-lying placenta, sex is perfectly safe. The baby is safely cushioned inside, so don't stress about it.
Our elders sometimes tell us to avoid it in the first few months just to be cautious. Honestly, it's best to ask your doctor directly so you and your husband are both stress-free.
In most normal pregnancies, intimacy is completely safe and won't harm the baby at all. But if you have had any previous complications or bleeding, please check with your doctor first. Don't worry, you are doing great!
Generally, it is safe and does not cause miscarriage. Just be gentle, and definitely ask your gynac if you feel any discomfort or if they advised bed rest.
Usually, sex doesn't cause miscarriage because the baby is well-protected in the amniotic sac. But to be safe, just ask your doctor during your next visit if you have any complications like spotting.