Job is more physically taxing is it advisable to resign as im pregnant?

Im in the first trimester and the nature of my job scope requires much labour work like carrying of heavy stuff, alot of walking, standby for any alarms 24/7 and work on weekend for any rectification works. Is it advisable for me to resign due to the nature of the job? Understand that there are no more admin headcount required but it is not easy to get a new job while pregnant.