what do they mean by....

A baby born at 32 weeks is about 8 weeks premature, since average normal pregnancies are about 40 week in duration. Their "corrected" age reflects their "post-conception" age or how old they would be if the pregnancy had gone to term. The baby in your example would then be chronologically 18 weeks old but developmentally only 10 weeks old. 10/52 is an abbreviation for 10 weeks.