I would assume they relax and stretch along with the uterus, since the uterus is a muscle as well. In certain cases though you can have a diastasis recti which is when the most outer layer of muscle splits in the middle and this can cause what looks like a valley in the abs later on after baby is born.
The Eastern Time (ET) or Eastern Standard Time (EST) is also known as North American Eastern Standard Time. It is the time zone that pertains to the east coast of North America. The clock time in the Eastern Time is based on the mean solar time of the 75th meridian west of the Greenwich Observatory in London.
Eastern Time, Eastern Standard Time, EST (noun). standard time in the 5th time zone west of Greenwich, reckoned at the 75th meridian; used in the eastern United States. see more on Definitions.net Â».