A cautious team approach to managing pregnant women with glaucoma is necessary to reduce risks for both the patient and the foetus, according to a new study published in the Current Opinion in Ophthalmology.The study found there is a lack of data on treating glaucoma during pregnancy and lactation and that the risks of glaucoma medications in pregnancy are to a large extent unknown. Clinical trials pose legal and ethical difficulties.
Study author and glaucoma specialist Dr. Sarwat Salim from the UT Medical Group in Memphis, Tennessee, said although brimonidine, a category B medication, is presumed safe, this is only due to animal studies. She said other glaucoma medications, including prostaglandin analogs, parasympathomimetics, carbonic anhydrase inhibitors and beta blockers, which are category C medications, have not been deemed as safe due to adverse effects reported in animal studies and a lack of human studies.
Sydney glaucoma specialist Dr. Ivan Goldberg agrees with a cautious approach but feels there are strategies available to help reduce risks.
“When eye drops are instilled to treat glaucoma, some of the active agents will be absorbed into the general circulation,” said Dr. Goldberg. “They can pass through the placenta and reach the foetus. If a baby is being breast-fed, they can pass into the milk, thus reaching the baby’s circulation as well.”
He said special techniques when instilling eye drops – such as the double dot (‘don’t open the eyes’ and ‘digital occlusion of the tear duct’) – can reduce the amount of medication absorbed into the blood by up to two-thirds, which may reduce side effects but cannot be guaranteed to protect the unborn or newly born child.
Dr. Goldberg said it is important that women with glaucoma who are planning a pregnancy discuss their plans with their ophthalmologist. “Eye pressure tends to drop during pregnancy and this can make treatment less necessary. However, some women might elect for laser trabeculoplasty or even surgery to lower eye pressure before pregnancy to eliminate or reduce the need for eye drops.”
“With provisos, beta blockers are probably safe to use during pregnancy up to a week or two before delivery, as are carbonic anhydrase inhibitors. Prostaglandin agonists should be avoided during pregnancy, while prostaglandin analogs are likely to be safe post-delivery.”
Dr. Goldberg said alpha 2 agonists may be safe during pregnancy but should be used with care before delivery and are contraindicated during lactation.X`
“In principle, however, any agent carries risks to the foetus during pregnancy and to the new-born during lactation.”