How many miscarriages or spontaneous abortions can a woman have in their life?

I have had 4 confirmed miscarriages. One at 6 weeks, one at 10 weeks, one at 12 weeks and the loss of identical twins at 16 weeks. I am now 15w4d pregnant and have been panicking and worrying all the way through. I have decided that if i loose this baby i won't try again because i can't bear to go through with all the heartache.