Sentence:  Since one of the principal reasons for keeping the <WSD>puerpera</WSD> in a recumbent posture is avoidance of strain upon relaxed and weakened supporting structures by a large heavy uterus, the length of the stay in bed is not made a matter of routine 
Meaning of the word marked with <WSD> tags:  A woman undergoing puerperium; a woman whose uterus is still enlarged from pregnancy.