Background. Decrease in intraocular pressure （IOP） during pregnancy has been reported by previous studies

but amount of decrease varies from study to study. Moreover

previous studies have concentrated on the last trimester of pregnancy or one reading per trimester. IOP changes throughout the pregnancy have never been described. Therefore

the present study was planned to determine IOP throughout the pregnan cy

after placing control on IOP affecting factors.Subjects and methods. Thirty-six pregnant and same numbers of non-pregnanat women of the same age group were studied. IOP measurements were taken at four week intervals throughout the pregnancy

with the Goldmann applanation tonometer.Results. As compared to control subjects

up to 8th week

IOP remained the same. At 12th week

it becomes significantly lower. The IOP differences between fIrst and second （P<0. 05）

and second and third （P<0. 001 ） trimesters of pregnancy were significant. In every subject

IOP decreased during pregnancy.However

there were variations among individuals in the extent of IOP decrease Conclusbos. With advancing pregnancy

intraocular pressure decreases. Knowledge of the normal level of intraocular pressure in various stages of pregnancy may help glaucoma screeners.