Hello, Welcome to HCM, I am Dr. Das
For
pregnancy you do not need too much
sperm count. Along with sperm count, most important is
sperm motility and sperm morphology. According to WHO 1999, requirement of sperm count is >20 millions / ml, requirement of sperm motility is >50%, and minimum 60% sperms should be of normal morphology.
To fertilize a ovum, a sperm has to go up to the
fallopian tube. If motility is lower than required, then the sperms are unable to fertilize a ovum in spite of having normal sperm count.
So, for pregnancy you need 50% sperm motility and 60% normal sperm.
From the above discussion it is clear that no definite comment can be done regarding pregnancy on the basis of only 31 million sperm.