Diabetic retinopathy in pregnancy

Pubblicato il

Wednesday, 17 May 2023

Argomento

Retina

The gestational diabetes is characterised by an elevated blood glucose level, which occurs during pregnancy and usually disappears after delivery. It can occur at any time during pregnancyalthough it is more common in the second or third trimester, and is due to a lack of insulin in the blood. Insulin, in fact, is a hormone that helps control sugar levels in the bloodstream. Gestational diabetes can cause problems for mother and baby, both during pregnancy and after delivery, and among its possible consequences is the development of diabetic retinopathy (DR) or the worsening of an already existing DR.

In the 1970s, proliferative diabetic retinopathy (PDR) was considered an indication for pregnancy termination. However, today, with the advent of screening procedures and advances in the management of gestational diabetes, women are able to continue their pregnancies with good control and excellent outcomes for both mother and baby.

Characteristics of diabetic retinopathy in pregnancy

The incidence of DR in pregnancy strongly depends on the duration and control of diabetes and the presence of risk factors such as hyperglycaemia, hypertension, dyslipidaemia and nephropathy, which may accelerate the progression of retinopathy. In contrast, it is known that in women with pre-existing diabetes mellitus, pregnancy is associated with worsening DR. As the prevalence of type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) has increased globally, the incidence of RD in pregnancy has also risen, which is approximately 63% in T1DM and 14% in T2DM. Usually, the adverse effects of pregnancy on the retina occur by the end of the second trimester and regress after delivery, but some more severe cases may persist in the first year postpartum.

What are the risk factors?

Risk factors that may influence the development and progression of DR during pregnancy are poor glycaemic control during gestation, longer duration of diabetes before conception, rapid normalisation of glycated haemoglobin (HbA1c) at the beginning of pregnancy, hypertension and pre-eclampsia. On the other hand, if DR is already present, the stage and severity of DR at the time of conception have an impact on disease progression during pregnancy, as progression is more significant in pregnant women with moderate or severe forms of DR than in those with mild or no DR. In particular, studies have shown that 55% of pregnant women with moderate to severe DR and 21% of women with mild DR deteriorate and that in 9.8% of cases, progression to proliferative disease is observed. The most severe cases, which do not resolve in the first year postpartum, may lead to loss of vision.

Management of diabetic retinopathy in pregnancy

Screening for DR is a very important aspect of gestational diabetes management, as it aims to detect the condition early and initiate early treatment to prevent vision loss. Therefore, women with gestational diabetes should undergo retinal screening and receive counselling on the risk of development and progression of DR. In addition, they should be followed by a multidisciplinary team, consisting of an endocrinologist, an ophthalmologist and a perinatologist.

Throughout the pregnancy period, a comprehensive eye assessment should be performed and strict glycaemic control maintained. In fact, maximum control of glucose levels and blood pressure are essential in the treatment of DR during pregnancy. The duration of follow-up depends on the stage of DR: the more severe the retinopathy at diagnosis during the initial check-up, the more frequent the check-ups should be.

As for the treatment of RD in pregnancy, the advent of laser surgery has made it possible to manage this condition effectively. In contrast, first-line treatment with anti-VEGF should not be administered during pregnancy, particularly in the first trimester, due to the high risk of miscarriage. Intravitreal steroid injection may be considered for diabetic macular oedema refractory to treatment, but preferably in the 2nd or 3rd trimester of pregnancy. The possibility of surgery should be postponed until after delivery or performed under local anaesthesia, not earlier than the trimester before birth.

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