Kerala Journal of Ophthalmology

PERSPECTIVES
Year
: 2021  |  Volume : 33  |  Issue : 1  |  Page : 8--11

Glaucoma in pregnancy: An update and practical guide


Sirisha Senthil1, Dhanya Cheriyath2,  
1 VST Glaucoma Center, L V Prasad Eye Institute, Banjara Hills, Hyderabad, Telangana, India
2 Department of Glaucoma, Jyothis Eye Care, Kannur, Kerala, India

Correspondence Address:
Dr. Sirisha Senthil
L V Prasad Eye Institute, Kallam Anji Reddy Campus, L V Prasad Marg, Road No 2, Banjara Hills, Hyderabad - 500 034, Telangana
India

Abstract

Lack of clear guidelines and understanding makes management of glaucoma during pregnancy a major challenge. The treatment should be balanced in such a way that it is safe for the mother and the growing fetus while maintaining the intraocular pressure control and stability of glaucoma.



How to cite this article:
Senthil S, Cheriyath D. Glaucoma in pregnancy: An update and practical guide.Kerala J Ophthalmol 2021;33:8-11


How to cite this URL:
Senthil S, Cheriyath D. Glaucoma in pregnancy: An update and practical guide. Kerala J Ophthalmol [serial online] 2021 [cited 2021 May 7 ];33:8-11
Available from: http://www.kjophthal.com/text.asp?2021/33/1/8/314095


Full Text



 Introduction



Pregnant women may have preexisting glaucoma from childhood that may need monitoring.[1] Managing glaucoma in pregnant women is a challenge for both the patient and the treating doctor.[2] The intraocular pressure (IOP) is known to reduce linearly as pregnancy advances.[3],[4] However, close to one-third of the women have elevated IOP,[5] and those with preexisting glaucoma may worsen needing additional medical treatment, laser, or surgery.[6]

The management benefits have to be weighed assessing the benefits of treatment versus the potential risks for both mother and the fetus.

The paucity of literature due to ethical and legal constraints in conducting clinical trials on pregnant women leaves us with no evidence-based guidelines for the management of glaucoma in pregnancy. In this article, we discuss the practical considerations in medical management, laser therapy, and surgical intervention for glaucoma in pregnant women.

 Medical Management



According to the United States Food and Drug Administration (FDA), none of the antiglaucoma medications (AGMs) are considered safe in pregnancy.

[Table 1] shows the FDA classification of AGMs based on the safety profile of the drugs.[1]{Table 1}

The only antiglaucoma medication available in Category B is topical alpha agonist.[1] Category C drugs include topical beta-blockers, prostaglandin analogs, topical and oral carbonic anhydrase inhibitors, and parasympathomimetics.

AGMs have potential side effects at various stages of pregnancy. The risks include teratogenicity in the first trimester, premature labor in the second and third trimester, and potential toxicity to the new born due to the secretion of the drug through the breast milk during postpartum and lactation. Each class of medication has special concerns for usage during pregnancy and lactation.[1]

[Table 2] shows the recommended class of AGMs according to the trimester of pregnancy.{Table 2}

Beta-blockers

Oral beta-blockers are classified as Category C drugs;[1] however, beta-blockers are used to treat hypertension during pregnancy.[7] Topical beta-blocker may cross the placenta and cause fetal bradycardia, and beta-blockers may cause neonatal respiratory distress and apnea due to secretion into breast milk.[1]

Alpha agonists[1]

Brimonidine is a Category B medication. Although well tolerated, its use should be discontinued close to labor and during lactation due to its potential side effects of central nervous system depression and apnea in infants.

Prostaglandin Analogues[1]

Prostaglandin Analogues (PGAs) are Category C drugs shown to be associated with miscarriages in animal studies. It can stimulate uterine contraction producing preterm labor; however, it is unclear whether ophthalmic dosage can induce this side effect. Given this theoretical risk of premature labor, PGAs are not used as the first line of medication during pregnancy.

Carbonic anhydrase inhibitors

Topical medications are classified under Category C. Animal studies have shown that both brinzolamide and dorzolamide cause teratogenicity and low birth weight.[1] There is no convincing evidence for the adverse effect of acetazolamide in pregnancy. However in early pregnancy, <13 weeks of gestation using oral carbonic anhydrase inhibitor (CAI) is not recommended but could be used with caution in the second and third trimester.[8],[9] The use of oral CAI in late pregnancy needs close monitoring as it can cause neonatal electrolyte imbalance and metabolic acidosis.[1],[2],[10]

Cholinergic medications

There is no known association between the use of topical pilocarpine and congenital abnormalities; however, few instances of hyperthermia and seizures in neonates were recorded and hence may be avoided during postpartum and lactation.[1],[10]

Other Drugs

Rho-associated protein kinase inhibitors when used systemically may cause excessive vasodepressor action. Although topical use of these medications minimizes the undesirable adverse effects, there are concerns about the effects of long-term usage and tolerance to the drug.[11],[12] There is no published evidence on its use in pregnant women.

Drainage of the drug through the nasolacrimal duct, lack of ocular metabolism, and bypassing hepatic enzymatic metabolism causes systemic absorption of drugs[13] and exposes the fetus to the side effects of AGMs.[1],[2]

Simple techniques such as punctal occlusion and eyelid closure can reduce systemic absorption.[1] Medical management requires a fine balance between the risk of vision loss to the mother and the side effects of AGMs on the fetus.[1] Hence, pregnant women should be prescribed minimum medications and only when necessary.

 Laser Therapy



Selective laser trabeculoplasty is a useful alternative to reduce the number or need for AGMs and possibly defer surgery in pregnant women.[14],[15] However, inability to perform laser trabeculoplasty in dysgenetic angles, lower efficacy in young patients, delayed onset of IOP reduction,[1] and compromised long-term IOP control limits its use.[16] There is scant literature on the use of micropulse or diode cyclophotocoagulation to control IOP during pregnancy.[17] Given the SHORT TIME FRAME OF PREGNANCY, trabeculoplasty should be considered whenever feasible.[2]

 Glaucoma Surgery



Surgery is best avoided during pregnancy. However, IOP can increase and preexisting glaucoma can worsen despite medical and laser treatment.[2],[5],[18] Failure of conservative management combined with disease progression makes surgical intervention inevitable.[19] Glaucoma surgery during pregnancy has serious risks. Challenges are related to preoperative planning, anesthetic concerns, intraoperative modifications, and postoperative management.

Altered maternal physiology predisposes pregnant women to hypoxia, hypercapnia, and systemic hypotension, which exposes both mother and fetus to the risk of anesthesia, more so with general anesthesia.[1] Additional challenges include difficult airway management because of gastroesophageal reflux and increased risk of aspiration. Placental transfer of anesthetic agents such as narcotics, paralyzing agents, and inhalational agents can cause fetal cardiovascular and central nervous system depression.[18] There are no well-controlled human studies on the teratogenic effects;[8] however, reports show an increased incidence of low birth weight and neural tube defects with exposure to general anesthesia in the first trimester.[9] Local anesthetics used in current ophthalmic surgeries have not shown teratogenic effects in humans and are considered relatively safe in pregnancy.[19] However, fetal bradycardia was noted with bupivacaine but not with lidocaine.[20] Topical anesthesia augmented with subconjunctival and anterior sub-Tenon's anesthesia causes less systemic absorption of anesthetic drugs,[21] and hence, it is advisable to limit the drugs to the minimum required dose for effective analgesia.

Supine position in the second and third trimester can cause profound systemic hypotension as the gravid uterus tends to compress the aorta and vena cava. It is advisable to rotate patients' hip, abdomen, and thighs to the left lateral position while maintaining a normal head position for surgery. As chances of gastroesophageal reflux are high, the full stomach should be avoided during surgery.[1],[19] It is advisable to defer surgery till the second trimester to prevent potential hazards of teratogenic anesthetic agents on the fetus.[22] However, the risk of surgery also increases substantially as the fetus grows in the second and third trimester.[1]

Although there are no studies that report the teratogenic effects of mitomycin C or 5 fluorouracil on the human fetus, the mechanism of action of the drug strongly suggests a potential hazard of teratogenicity, and hence, it is safer to avoid antimetabolites during pregnancy.[1],[22],[23] However, because of a high risk of bleb scarring in young patients, a subconjunctival, biodegradable, collagen (Ologen) implant can be used as an adjunct to modulate wound healing and prevent subconjunctival fibrosis.[24]

Topical antibiotics can be used judiciously in the postoperative period.

A study on fluoroquinolones (a Category C drug by FDA) shows no risk of congenital anomalies.[20] Category D drugs, tetracyclines, and aminoglycosides are considered unsafe in pregnancy. Topical corticosteroids are the routine postoperative medications following glaucoma surgery. Given the strong neeed to use steroids and the absence of clear complications associated with topical steroids, it can be used in pregnant women.[1]

Homatropine hydrochloride 2% eye drops and Atropine sulfate 1% eye drop can be used, as the ophthalmic dosage of these drugs is less likely to affect the fetus. However, homatropine might be a better option, as atropine may cause fetal bradycardia.[8]

All topical medications should be prescribed with punctal occlusion and eyelid closure to reduce systemic absorption. Patients should be advised to avoid blinking immediately after instillation of eye drops as blinking can activate the lacrimal pump and increase systemic absorption.[1],[20] However, utmost care and caution should be exercised during punctal occlusion in the early postoperative period, avoiding additional pressure on the eyeball, and taking appropriate hygienic precautions.

 Summary



Management of elevated IOP during pregnancy differs based on the trimester of pregnancy, the severity of the disease, and risk versus benefit of treatment. Although IOP is known to decrease during pregnancy, some patients develop uncontrolled IOP not amenable to medical treatment and may need laser trabeculoplasty or surgery. If surgery is indicated, it might be safer to perform the same during the second trimester.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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