March 2020

GLAUCOMA

Research Highlight
Controlling glaucoma in pregnant patients


by Maxine Lipner Senior Contributing Writer

Management of glaucoma in patients who are pregnant can present ophthalmologists with new considerations. Investigators in a recent study1 determined that IOP can actually be lower in pregnant women, according to Barbara Wirostko, MD. Challenges include that some medications could have adverse effects on the fetus and newborns.

Evaluating issues

Management of this population of patients is particularly difficult due to their hemodynamic status and concerns about how any medications used to treat glaucoma may impact the fetus or even the newborn after birth via breast milk, Dr. Wirostko said. For example, when it came to the use of beta blockers, investigators found two papers2,3 showing that breast milk concentration was 3 to 6 times higher than plasma of a lactating female. It can cause bradycardia in newborns, Dr. Wirostko reported. Brimonidine should also be used with caution postpartum4,5 because “it has significant CNS depression, apnea, and hypotensive effects on young individuals,” Dr. Wirostko said, adding that it’s eye-opening how much of the drug could be concentrated in the breast milk.
Investigators also considered the fact that prostaglandins, although not those used to treat glaucoma, are used to induce labor. This is something that Dr. Wirostko keeps in mind. “I think it behooves us not to use prostaglandins in the last trimester, if we can avoid them,” she said. Not much is known about various topical vascular-modulating drugs and their effect on smooth muscles. “We don’t know how they react and interact with blood pressure and blood volume in pregnant women and uterine smooth muscle,” Dr. Wirostko said.
The fact that the study found IOP was lower in pregnant women was not surprising to Dr. Wirostko. “One of the things that changes for women when they’re pregnant is the blood volume expansion, but also the vasodilation with there being an inverse relationship with estrogen and progesterone,” she said. This may translate into less of a pressure-lowering need for women during pregnancy.

Clinical possibilities

In cases where IOP lowering is needed, however, Dr. Wirostko said SLT is a good option. “I think also if the patient knows that they want to get pregnant, then you can do the laser ahead of time and see if you can get them off of their medications while they’re trying to conceive,” she said.
Use of MIGS may be another possibility. “The only problem with MIGS is that some of the shunting procedures have to be performed at the same time as cataract surgery in order to get reimbursed,” Dr. Wirostko said.
Other surgical approaches may be problematic as well in pregnant women due to increased levels of VEGF and platelet-derived growth factor in the blood, she continued, adding that a lot of these proteins and cytokines can induce scar tissue. This may raise questions as to whether a pregnant woman would be a good candidate for a trabeculectomy, for example. The need for anesthesia may also play a role when considering glaucoma surgery. “We generally prefer not to put pregnant women under anesthesia,” Dr. Wirostko said.
If using a medication to lower IOP, a beta blocker would be preferable. “Obstetricians use beta blockers quite comfortably during pregnancy,” she said. “I think as clinicians that gives us comfort in using a topical beta blocker during pregnancy.” The fact that beta blockers are also used in children and have been around longer than most glaucoma medications also adds to this comfort level, Dr. Wirostko said.
Due to ethical and legal concerns Dr. Wirostko doesn’t envision a time when it would be possible to run a prospective trial on pregnant women with glaucoma. “I think it’s just collecting data where we can and being mindful that the fetus is getting exposure to plasma and that there also may be ingestion of drug through breast milk,” she concluded.

About the doctor

Barbara Wirostko, MD
Adjunct professor of ophthalmology and biomedical engineering
University of Utah
Moran Eye Center
Salt Lake City, Utah

References

1. Mathew S, et al. Management of glaucoma in pregnancy. J Glaucoma. 2019;28:937–944.
2. Lustgarten JS, Podos SM. Topical timolol and the nursing mother. Arch Ophthalmol. 1983;101:1381–2.
3. Morselli PL, et al. Placental transfer and perinatal pharmacokinetics of betaxolol. Eur J Clin Pharmacol. 1990;38:477–83.
4. Fudemberg SJ, et al. Efficacy, safety, and current applications of brimonidine. Expert Opin Drug Saf. 2008;7:795–9.
5. Coleman AL, et al. Medical therapy in pregnancy. J Glaucoma. 2005;14:414–6.

Relevant disclosures

Wirostko
: None

Contact

Wirostko: barbara.wirostko@hsc.utah.edu

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