My doctor said physical activity and intimacy are fine, but just be careful. Since I had GD, I was always extra cautious about everything, but medically it's usually safe.
I had to do regular follow-ups for my thyroid, and I asked my doctor about intimacy too. She said it is perfectly safe as long as there is no bleeding or high-risk issue.
From a religious standpoint, it is generally allowed, but honestly, your doctor's advice is what matters most. If your gynac says you have a low-lying placenta or any risk, then you must avoid it.
I was actually wondering about the medical side of this too since we are planning to conceive soon. From what I've read, as long as your pregnancy has no complications, it is totally fine.