Many men are concerned about hurting their pregnant partner, or their baby, when having intercourse during late pregnancy. Penetrative sex won't hurt your unborn baby. The
cervix is sealed with a thick mucous plug that helps prevent infection and the bag of waters (membrane) and amniotic fluid, act as a cushion to protect your baby.
A frequently asked question is "Will orgasm start labour?" The answer to this is "No", unless her body is already prepared to start labouring, near the end of the pregnancy.
The uterus (or womb) is an organ that contracts regularly from the time of a girl's first period to menopause (when she stops menstruating). During the last months of pregnancy the uterus is quite active with Braxton Hicks contractions. These are the practice contractions, the 'dress rehearsals' for labour.
When a pregnant woman has an orgasm, she will usually experience some Braxton Hicks contractions for a few minutes afterwards. This is normal and will not start the labour. (Sex is now not believed to be a cause for
premature labour. If your partner starts labouring prematurely, her body was preparing for this anyway. It is not because you have had sex recently). Towards the end of the pregnancy as her body prepares to go into labour,
prostaglandins in your semen and her experiencing an orgasm are capable of triggering and stimulating labour contractions to start, but a woman's body must be 'ready' to react in this way.
When having sex during late pregnancy, different sexual positions may need to be explored as her belly gets bigger. The conventional missionary position (partner lying on top of woman) can be a bit tricky, but fine if your weight is held off her. Other positions you can try include laying side by side with you behind her, the woman on top, or her being on all fours, with you behind. You can read more in
sex during late pregnancy.