The Health department has revealed that five expectant mothers recently died of malaria in three health facilities in Kisumu within a month.
The deaths were reported at Muhoroni, Kombewa and the Jaramogi Oginga Odinga Teaching and Referral Hospital in October 2016.
The department said the number is the highest ever recorded in a single month in the last three years.
Kisumu County Malaria Control Unit coordinator, Lilyanna Dayo, said the deaths have become a concern given the huge investment made in the fight against the treatable disease.
"We have enough anti-malarial drugs in all the hospitals across the county, with over 90 percent mosquito net cover and a number of community health workers, hence losing lives to malaria is a big worry to us," said Dayo.
"When an expectant mother dies, we lose two lives, hence we are very concerned with the deaths, especially when it is something which can be avoided."
Statistics from the National Malaria Control Unit indicate that a few people make good use of mosquito nets, contributing to the rising number of deaths.
Dayo said every pregnant woman attending ante-natal clinic will now be tested for malaria, given free medication and a mosquito net.
"We have now instructed our community health workers to monitor the use of nets and anti-malarial drugs in their respective areas of coverage. We have also intensified advocacy and social mobilisation," she said.