J.B.
I've never taken the shot but I'm a nurse and I'm familiar with the perscription. Progesterone is the hormone your body naturallu produces when you are pregnant. It is how your body recognizes that it needs to make preperations for a baby instead of a menstrual cycle. In your normal monthly cycle there is a spike in progesterone followed by a decline in it... this decline signals to your body that it is time for your menstrual cycle. In many cases of miscarriage it is because the womans body is not maintaining a high enough level of progesterone and therefore the body does not realize that it is pregnant and instead goes into menses. So, your baby should not experience negative side effects because this is what your body should be doing naturally. Talk with your doc, but most likely, for whatever reason, near the end of pregnancy your body starts to decline its production of progesterone causing you to have pre-term labor. Be sure that they are checking your levels periodically to make sure that the dosage is right for you. As far as side effects for you goes, it sounds like you have some pretty good responses regarding soreness at the injection site, etc. Also, don't be surprised if you experience some mild hormonal effects... progesterone is testosterone, the hormone that men naturally produce all the time and the hormone that generally makes preganant woman have hormonal effects. Good luck!