weight gain 

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4;T;X;15;O20;O26.0;O26.0;O260;Excessive weight gain in pregnancy;242;UNDEF;UNDEF;2-067;1-089
4;T;X;15;O20;O26.1;O26.1;O261;Low weight gain in pregnancy;242;UNDEF;UNDEF;2-067;1-089

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if($big_string=~/$small_string/) {print "Found match\n";}

##</code><code>##

Excessive weight gain in pregnancy
Low weight gain in pregnancy