Geez, what do you know we finally agree on something. 3 months you're fairly safe but the fetus can die at anytime right up till birth (still born) and sadly the mother and child can die as well. You're also right about a miscarriage and the woman doesn't know they were actually pregnant.
My English cousin had three children. Her first was a son and was a 7 month preemie and never lost the hospital and died at 3 months. Her next two daughters were both 7 month preemies as well but survived. The second daughter is now 7 months and doing very well so far anyway. Just hope for the best and hope that history doesn't repeat itself.
