I'll echo the others who said go for it as long as your doctor didn't tell you to avoid it.
From what I remember there are no drawbacks and towards the end of your pregnacy it might be recommended to have sex to avoid being induced (I was induced for my last child despite trying this).
Once the baby arrives, it's likely that sex will dry up for a while if you have a vaginal birth since you'll need to mend, so enjoy it while you can.