You can't have a miscarriage at 23 weeks. Its called pre term labor then. Call your doctor if your having pains or bleeding. She'll tell you if you need to go to er. I went into preterm labor and they kept me in the hospital for athe last month and a half if my first pregnancy. They will give you shots to stop the labor and some other medicine in an iv. You'll be on bed rest till the baby comes.
It can happen at any point in pregnancy but 12 wks is usually the point where your out of the "at risk" period. If you are experiencing problems then I wouls suggest you speak to your doctor or midwife. The symptoms could vary from bleeding, extreme pain and lack of movement but movement is a tricky one as lots of women feel movement at different stages. If your concern ring someone x