<prompt> Area of mitral valve in severe mitral stenosis during pregnancy4-6 cm21.5-2.5 cm21-1.5 cm20.8-1 cm2  <response>: Normal area of mitral valve is 4-6cm2 Symptoms usually appear when stenosis 2.5cm2 Severe mitral stenosis is less than 1.5cm2 Critical area is less than 1cm2- High rate of Pulmoary edema55 and Arrhythmia33 Reference: Williams Obstetrics; 24th edition; chapter 49 DC.Duttas ,9th edition,page 260 