Here is an article about maternity clothes like maternity sweaters, maternity overalls, maternity suits, and overalls. Previously, women did not pay special attention to fashion in the pregnant months. They just preferred to wear loose fitting clothes.
It was not until the Middle Ages that the clothes worn by people followed the shape of the body. European women used to wear seamed dresses. When a woman became pregnant, she would open the sutures to allow growth to take place freely. They wore a kind of dress that was less hips and had many folds. Maternity dresses were especially fashionable during the Georgian era.
But the days when women had to wear the same clothes during pregnancy are over. Now there are different and different clothes for pregnant women like maternity overalls, maternity overalls, maternity sweaters, etc.