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.
Going strictly by meridians all of Florida should be in the Central Time Zone, but the railroads wanted all of the US east coast to be in the same time zone every location west of Washington, DC located on the east coast was dumped into the Eastern Time Zone, which, of course includes all of Florida except a few counties in the Florida panhandle.