Should I wait until my second missed period to do a pregnancy test? With my 2 kids, didn't find out until after 8 weeks.

No. Don't wait. To get optimal prenatal care, find out as soon as you can. Urine tests usually turn positive 10-14 days after a missed period. Blood tests turn sooner. Both tests check for HCG hormone, present during early pregnancy. Some women have a HCG variation that is normal but tests may not detect it. If you have symptoms similar to other pregnancies, this is probably your best pregnancy indicator.