Once hpt becomes negative (after abortion) will you ovulate right away/the same day?

Nature isn't exact: After a pregnancy ends, either naturally or by medical means, one's body takes some time to readjust and start one's hormones (there are several hormones involved) cycling again. One cannot predict when one's first ovulation is, and one can get pregnant with that first new egg (even before a menstrual period returns). So, one must use reliable contraception now, if another baby is not desired.