Here is an article about maternity wears like the maternity sweaters, maternity overalls, maternity rompers and jumpsuits. Previously women did not pay much heed to fashion during their pregnant months. They just preferred wearing loose fitted clothes.
It was not until the middle ages that clothes worn by people followed the shape of the body. European women used to wear dresses that had seam. When a lady used to get pregnant she would open the seams so that the growth can happen without any hindrance. They used wear a type of gown which was waist less and had many folds. Maternity dresses came into vogue mainly during the Georgian period.
But gone are those time when women have to wear the same dresses even during their pregnancy. Now different and varieties of clothes are available for pregnant women like maternity jumpsuits, maternity dungarees, maternity sweaters etc.