Background: Systemic blood pressure is positively related to intraocular pressure. During the third trimester of pregnancy decreased intraocular pressure while increased blood pressure has been reported. After taking into account all those factors that can affect intraocular pressure, the present study investigated whether or not the high blood pressure found in late pregnancy influences the known ocular hypotensive effect of late pregnancy.
Subjects and methods: Normotensive subjects in all trimesters of pregnancy and non-pregnant control groups along with third trimester hypertensive subjects were studied. Intraocular pressure was measured with the Goldmann applanation tonometer.
Results: In the second and third trimester subjects, the mean intraocular pressure was significantly lower than in the non-pregnant control group. The differences between first and second, first and third, and second and third trimesters of pregnancy were (mean +/- s.d.) -0.5 +/- 1.2 (p < 0.05), -1.5 +/- 1.7 (p < 0.001), and -1.0 +/- 2.1 (p < 0.01) mmHg respectively. The mean difference between third trimester hypertensive and third trimester normotensive pregnant women was 0.53 +/- 1.5 mmHg (p < 0.05).
Conclusions: With advancing pregnancy, intraocular pressure decreases. The mean intraocular pressures of third trimester hypertensive pregnant women were significantly higher from that of third trimester non-hypertensives. Knowledge of the normal level of intraocular pressure in various stages of pregnancy may help glaucoma screeners.