Not only pregnancy but also the number of fetuses in the uterus affects intraocular pressure

Abstract

Aim:To investigate whether, intraocular pressure (IOP) is affected when there is a second fetus in the uterus during pregnancy.Materials and Methods:Eighty eyes of 40 twin pregnancies (TwPs), 80 eyes of 40 singleton pregnancies (SiPs) and 80 eyes of 40 non-pregnant females (NoPs) were included in the study.Statistical Analysis:Repeated measurements analysis of variance with two factors, one-way analysis of variance (ANOVA) and theTukey's multiple comparison test were used.Results:The mean IOP (MIOP) values in TwPs were 14.29 ± 1.28, 11.48 ± 1.20, and 9.81 ± 1.36 mmHg and the MIOP values in SiPs were 14.42 ± 0.95, 13.12 ± 0.75, and 10.97 ± 0.89 mmHg in subsequent trimesters. The MIOP values in NoPs were 14.77 ± 1.18, 14.92 ± 1.33, and 15.08 ± 0.89 mmHg in subsequent 3-month measurements. The results show that the MIOP values for the TwPs group were significantly lower than the SiPs in all trimesters.Conclusions:During pregnancy, the number of fetuses in the uterus is an indirectly important factor that influences the decrease in IOP. We hypothesize that the increased ocular hypotensive effect of TwPs is most likely related to the presence of higher levels of hormones, particularly estrogen, progesterone and relaxin compared with SiPs.

The ocular hypotensive effect of pregnancy

“…Saylik and Salik [11] have confirmed that not only pregnancy but also a number of fetuses in the uterus affects IOP.…”

Intraocular pressure variation in pregnancy: a prospective study

“…11,12 Episcleral venous pressure has been reported to decrease in pregnant women could be associated with a decrease in general peripheral vascular resistance during pregnancy and might contribute to a decrease in IOP. 13,14 In our study, the mean IOPs in the second and third trimesters of pregnancy right eye were found to be lower than first trimester by 9.33% and 20.33% respectively & 14.2% and 28.84% left eye. The physiological changes in late pregnancy may reduce corneoscleral rigidity, making the results of applanation tonometry falsely low.…”

“…Proposed mechanisms underlying the decrease in IOP during pregnancy indicate an association between female hormones and increased outflow. 3,13,14 A marked increase in aqueous outflow facility can be associated with progesterone levels in pregnancy. The decrease in IOP with the use of progesterone or the combination of progesterone and estrogen at pharmacologic doses is also reported.…”

“…15 This ocular hypotensive effect seems to increase until delivery and may persist for several months postpartum. [12][13][14][15] A greater reduction of intraocular pressure was noted among pregnant women with baseline ocular hypertension in one study. 14 Another investigation showed that the reduction in intraocular pressure was greater among multigravida than primigravida women.…”

“…[12][13][14][15] A greater reduction of intraocular pressure was noted among pregnant women with baseline ocular hypertension in one study. 14 Another investigation showed that the reduction in intraocular pressure was greater among multigravida than primigravida women. 13 IOP for the post-partum period could not be checked due to difficulty of follow up of patients.…”