More than a half of women in Eastern province do not use any family planning method.
"Fifty two per cent of women in the province do not use any form of family planning due to negligence, poverty and accessibility thus accelerating unplanned babies and HIV/Aids infection," says study.
According to the study by the National Council for Population and Development, poor family planning methods in Makueni county is impacting negatively on population explosion with 12.5 per cent of teenage births contributing to a high growth rate of 2.5 per cent.
Many girls were found to be practicing sex at very tender age due to poor environmental circumstances and those using the four family planning methods of barrier,hormonal,surgical and natural is too low.
The study has shown that young mothers between 15-25 years have been increasing in a big margin due to unplanned pregnancies and unprotected sex.
"Most of these mothers cannot tell who the father of their babies are since they had not planned for the pregnancies and most of them have done it to look for survival due to poverty backgrounds and peer pressure from friends," the report says.
The study says the number of commercial sex workers aged between 15-24 years was going up very fast along the Nairobi-Mombasa highway and was the cause of the rising HIV/AIDS infection in the region.
It adds that with 3 percent growth rate of Kenya's population,it is estimated that the country's population by 2030 will be 71.5 million.
There is also a likelihood that this will increase poverty levels too if proper measures are not put in place.