Gestational age:Time:Pt:^Fetus:Qn:US+Estimated from GSD.Hellman 1969
gestational age:time:pt:^fetus:qn:us+estimated from gsd.hellman 1969
Gestational age estimated from Gestational sac diameter on US by Hellman 1969 method
gestational age estimated from gestational sac diameter on us by hellman 1969 method