hi,
welcome to Health care magic.com,,and thanks for posting..
regarding your query i will say there is neglible chances of being pregnant,,
why because pre cum contain very negligible amounts of sperms,,that too transferd from penis to mouth then mouth to mouth and finally to vagina...
sperms cant live in saliva as it contains many digestive enzymes which may destroy sperms...
secondly to become pregnant,number os sperms is not important indeed number of MOTILE sperms is necessary..that negligible amount of precum that too transferd from penis to mouth and finally to vagina cannot cause
pregnancy..no need to worry about this...
finally i will tell you one thing,,STD's that is
hiv,
syphilis and many other sexually transmitted diseases many transfr from 1 partner to another partner..so beware of that while you are with your partner..
hope you satisfied with my answer...
thank you
Dr Siddartha