At least seven Kenya Certificate of Secondary Education (KCSE) candidates in Isiolo County are heavily pregnant.
County Commissioner John Ondego said the girls, who come from different schools in the county, will continue to write their exams either in hospitals or examination centres.
Mr Ondego said the cases are not peculiar to Isiolo County only but are a countrywide problem.
"Such cases have been reported countrywide," the commissioner said.
An Education official, who requested for anonymity, said five other girls gave birth before the exams began.
A candidate who went into labour during the second day of examination is currently writing her papers at a private hospital in Isiolo town.
All the girls who gave birth before the onset of KCSE are sitting for their exams in their respective schools, the official said.
Last week, Education Cabinet Secretary Amina Mohamed decried the high number of teenage pregnancies reported during this year's national examinations.
The CS on Thursday ordered the quality assurance team in the Education ministry to investigate and file a report of all cases of pregnancies among school girls.
The CS noted that the move will enable the ministry to outline measures to curb such cases.
The minister urged parents to instil good discipline in their children through guidance and counselling to ensure such incidents are prevented.