My Sister Is 24',with Two.kids.younger Is Of 1 Year,problem Started

My sister is 24',with two.kids.younger is of 1 year,problem started when she was pregnent with second one,she aparently while talking or doing other stuff sudden gets restless,short breath,trying nreath hard by opening her mouth,but when.she feel.ok,she dont remember what happned to.her,kindly suggest