Jamie Lynn pregnancy....Jamie lynne is 5 months pregnant and not showing at all.... How does that happen?

Jamie lynne is 5 months pregnant and not showing at all.... How does that happen? and if she hidding her pregnancy what was the reason for her spilling the beans anyway? she wasnt that famous for her to come out and have to tell everyone she was pregnant anyway... so since it was up to her to tell the world why is she trying to hide the pregnancy? (IN MY OPINION)