When one is pregnant they might have a second thought before getting intimate or before having sex. But it is said that, if the health is permitting then one can do have physical intimacy even when the woman is pregnant.
In fact, sex in the third trimester is also possible and in general, sex during late pregnancy is totally safe. But yes, if one has certain conditions like placenta previa, recurrent miscarriage, previous pre term labour or some problems in the cervix then the gynaecologist may advise you to stay away from sex during the tenure of pregnancy.
Some women have notions that while having sex during pregnancy the partner might poke the baby. But this is not possible. There is a mucus plug, uterine muscles, cervix and ample fluids that cushion the way in between. But yes, the baby might experience some gentle rocking at the most and it can also happen in some other every day activities. There is simply no chance that the baby is going to end up with some physical disabilities or a dented head.
But yes having sex in the third trimester can be a bit difficult position wise. This is because one cannot be comfortable on their back when they are pregnant and the energy that it takes to go to the top is also not much possible during this condition.
So, the partners need to figure out what can be the comfortable position in this period. Pillows can be very useful during this time. This can build a shield and can provide a lot of comfort and one can also rest their body weight on the pillows as they never hurt as they are soft and cushion like. One can also try and linger on the second or the third base. If one wants to focus too much on the intercourse then it can put a lot of pressure on both the partners and it might turn out to be hectic and a non pleasant experience. So, sticking to foreplay is the best thing partners can think of during this time.
There are many studies that show that the orgasms during the third trimesters become more intense and the hormones course up the system more. In fact many women have reported that babies kick during the time of orgasms. But keeping balance is the most important thing during this time. Some unexpected positions may also work out which may not happen otherwise and so one has to be confident and keep trying different but safe positions.
But again if one feels uncomfortable in any way while doing it, then they should immediately stop. The partner has to understand that sex during pregnancy third trimester may be fun but it is also a tricky situation otherwise. So, when one feels a bit uneasy while having sex they should immediately stop because otherwise they may suffer from other physical issues which in turn can harm the pregnancy.
Otherwise it is completely safe to go for it.