Shouldn't moms no longer be phased by gross things anymore compared to before they were mothers?

Some girls look at stuff as "Ewww, gross". When women go through pregnancy, give birth, take of their baby and change those diapers, shouldn't the mother be much less phased by anything that would make someone's flesh crawl or go eww, gross? For example, if a woman always had a fear of spiders, shouldn't that fear or a big protion of that fear go away once she's a mom and has changed diapers? I mean, she's gotten used to gross stuff, so this should phase her less than, RIGHT?