Up until the 1950’s there were no fashionably designed maternity clothes for everyday wear.
Historically, in early days before fitted clothes this was not a problem, as the shapeless clothes were often larger than required and were cinched at the waist by belts, when a lady became pregnant the belt was simply worn higher.
By about 1600 onwards richer ladies actually had clothes designed that used a higher waistline to accommodate pregnancy, but were basically the same styles as those worn by other ladies of the time, but with substantially more material in the skirt.
Poorer ladies simply made do with their existing clothing – letting out (some even opening) side seams or maybe wearing a voluminous apron to cover where clothes no longer fastened.
In the 19th century many garments for wealthier ladies were actually tailored to HIDE pregnancy, their poorer counterparts were not so lucky and had to continue to make do with their normal wardrobe, perhaps wearing skirts higher on the body.
It wasn’t until the 1950s that fashion designers actually started to design proper maternity clothes, usually skirts and smock type tops or smock style dresses. By the late 1970s trousers had also become fashionable for the expectant mother, although the tops were still smock type.
Nowadays ladies require fashionable maternity clothes for the many different facets of their lives, from socialising to going to the gym, and pregnancy is no longer hidden away as it was in the past.