27wks preg.my blood grp is o+ve and hus's is a+ve.any problem to my baby becoz of this? i heard abt abo imcompatibility.is that a serious issue?

Could be an issue: If your baby is "a" and you pass anti-"a" antibodies to your baby, there is a risk for developing jaundice. This is treated easily if caught early. The baby's blood can be tested for these antibodies, as well as for jaundice (which again, can be treated.).

Nuscience not threat: ABO issues are more often a minor nuscience than a real threat. I remember giving a kid blood once after late anemia only once in 3+ decades as a pediatrician. If your infant is A+ (it might be O+) it might trigger mild issues that lead to more blood tests, but I wouldn't lose any sleep over the issue. I would put more time into staying healthy and sorting out how to deal with a newborn.