Retinal maturation is delayed by repeated, but not single, maternal injections of betamethasone in sheep.
OBJECTIVE
The safety and efficacy of prescribing a single maternal course of corticosteroid during pregnancy has been documented in human trials. However, the current trend is to prescribe repeated courses of corticosteroid. We investigated an aspect of the safety of this practice in an animal model.


METHODS
Date-mated ewes received saline, single or four corticosteroid injections between days 104 and 124 of gestation (term = 150). Lambs were delivered on day 125 or 145 by caesarian section after spinal anaesthesia. Eye diameters were measured and semi-thin toluidine-blue-stained transverse sections of retinae were analysed using an Optimus Image Analysis program.


RESULTS
At 125 days, retinal measures in the ventral periphery and area centralis were significantly thinner than control (p = 0.0001). At 145 days, total eye size was significantly reduced compared with control (p = 0.03), and retinal measures in the ventral periphery (p = 0.0001), but not the area centralis (p = 0.19), remained significantly different from control.


CONCLUSIONS
Repeated maternal administration of corticosteroid may affect retinal maturation in the fetus.
Quinlivan
J A
JA
Department of Zoology, University of Western Australia, Australia.
Beazley
L D
LD
Evans
S F
SF
Newnham
J P
JP
Dunlop
S A
SA
D000818:Animals; D001623:Betamethasone / Q000008:administration & dosage / Q000009:adverse effects*; D004334:Drug Administration Schedule; D005314:Embryonic and Fetal Development; D005123:Eye / Q000187:drug effects / Q000196:embryology / Q000473:pathology; D005260:Female; D005938:Glucocorticoids / Q000008:administration & dosage / Q000009:adverse effects*; D008431:Maternal-Fetal Exchange; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D012160:Retina / Q000187:drug effects* / Q000196:embryology* / Q000473:pathology; D012756:Sheep
D005938:Glucocorticoids; D001623:Betamethasone