Pregnancy does not induce or worsen retinal and peripheral nerve dysfunction in insulin-dependent diabetic women

Global Estimates of Diabetic Retinopathy Prevalence and Progression in Pregnant Women With Preexisting Diabetes: A Systematic Review and Meta-analysis

Importance

Diabetic retinopathy (DR) may be worsened by pregnancy in pregnant women with preexisting type 1 diabetes (T1D) or type 2 diabetes (T2D). Conflicting findings from previous studies have resulted in inconsistencies in guidelines regarding DR management in pregnancy. Global estimates of DR prevalence and progression in pregnancy are therefore required to provide clearer information about the overall true burden of DR in this population.

Objective

To estimate the prevalence of DR and its progression rate in pregnant women with preexisting T1D or T2D diagnosed before pregnancy.

Data Sources

For this systematic review and meta-analysis, conducted from November 27, 2018, to June 29, 2021, a systematic literature search was conducted in MEDLINE/Ovid, Embase/Ovid, and Scopus databases to identify English-language articles that were published from inception through October 2020.

Study Selection

Observational studies that reported on DR and its changes in pregnant women with preexisting T1D and T2D.

Data Extraction and Synthesis

Two independent reviewers extracted relevant data from each included study. Data were pooled using a random-effects model with the Freeman-Tukey double arcsine transformation. This study followed the Meta-analysis of Observational Studies in Epidemiology (MOOSE) reporting guidelines.

Main Outcomes and Measures

Prevalence of any DR, proliferative DR (PDR), and DR progression rates.

Results

A total of 18 observational studies involving 1464 pregnant women with T1D and 262 pregnant women with T2D were included in the analysis. The pooled prevalence of any DR and PDR in early pregnancy was 52.3 (95% CI, 41.9-62.6) and 6.1 (95% CI, 3.1-9.8) per 100 pregnancies, respectively. The pooled progression rate per 100 pregnancies for new DR development was 15.0 (95% CI, 9.9-20.8), worsened nonproliferative DR was 31.0 (95% CI, 23.2-39.2), progression from nonproliferative DR to PDR was 6.3 (95% CI, 3.3-10.0), and worsened PDR was 37.0 (95% CI, 21.2-54.0). DR progression rates per 100 pregnancies were similar between the T1D and T2D groups, except for the development of new DR (T1D groups: 15.8; 95% CI, 10.5-21.9; T2D groups: 9.0; 95% CI, 4.9-14.8). A global trend toward a lower DR progression rate was observed after the 1989 St Vincent Declaration.

Conclusions and Relevance

Results of this systematic review and meta-analysis suggest that women with T1D and T2D had a similar risk of DR progression during pregnancy. Despite improvements in the management of diabetes and diabetes during pregnancy, DR prevalence and progression in pregnant women with diabetes remains higher than the nonpregnant population with diabetes, highlighting the need to improve DR management in pregnancy.

Does parity worsen diabetes-related chronic complications in women with type 1 diabetes?

AIM: To determine the relationship between parity, glycemic control, cardiovascular risk factors and diabetes-related chronic complications in women with type 1 diabetes.

METHODS: This was a multicenter cross-sectional study conducted between December 2008 and December 2010 in 28 public clinics in 20 cities from the 4 Brazilian geographic regions. Data were obtained from 1532 female patients, 59.2% Caucasians, and aged 25.2 ± 10.6 years. Diabetes duration was of 11.5 ± 8.2 years. Patient’s information was obtained through a questionnaire and a chart review. Parity was stratified in five groups: Group 0 (nulliparous), group 1 (1 pregnancy), group 2 (2 pregnancies), group 3 (3 pregnancies), group 4 (≥ 4 pregnancies). Test for trend and multivariate random intercept logistic and linear regression models were used to evaluate the effect of parity upon glycemic control, cardiovascular risk factors and diabetes-related complications.

RESULTS: Parity was not related with glycemic control and nephropathy. Moreover, the effect of parity upon hypertension, retinopathy and macrovascular disease did not persist after adjustments for demographic and clinical variables in multivariate analysis. For retinopathy, the duration of diabetes and hypertension were the most important independent variables and for macrovascular disease, these variables were age and hypertension. Overweight or obesity was noted in a total of 538 patients (35.1%). A linear association was found between the frequency of overweight or obesity and parity (P = 0.004). Using a random intercept multivariate linear regression model with body mass index (BMI) as dependent variable a borderline effect for parity (P = 0.06) was noted after adjustment for clinical and demographic data. The observed variability of BMI was not attributable to differences between centers.

CONCLUSION: Our results suggest that parity has a borderline effect on body mass index but does not have an important effect upon hypertension and micro or macrovascular chronic complications. Future prospective evaluations must be conducted to clarify the relationship between parity, appearance or worsening of diabetes-related chronic complications.

Vascular complications in the diabetic pregnancy

Long-standing hyperglycemia frequently leads to vasculopathy. Microvascular disease is characterized by retinopathy and nephropathy, while macrovascular involvement can affect coronary arteries. Diabetic autonomic neuropathy, when present, is generally associated with retinal and/or renal involvement. Early identification of these diabetic complications allows appropriate counseling and early treatment. Among women with diabetic vasculopathy, nephropathy, chronic hypertension, preeclampsia, preterm delivery, and fetal growth restriction are frequently observed. Furthermore, women with impaired renal function in early pregnancy have increased risk of long-term deterioration of glomerular filtration rate. Proliferative retinopathy can progress during pregnancy and 1 year after delivery, but long-term effects are not likely to occur. When coronary artery disease or gastroparesis diabeticorum are present, excessive maternal and fetal morbidity is observed. When modern management is synchronized with early medical care, favorable maternal and perinatal outcomes can be expected.

Male-female differences in diabetic retinopathy?

The purpose of this paper is to review male-female differences in the incidence and prevalence of diabetes and diabetic retinopathy. These differences will be established primarily through results from our present research and a review of related literature. Previously, we have demonstrated that neuroretinal dysfunction can be used to predict the location of future retinopathy up to three years before it is manifest. Our current research suggests that, for type 2 diabetes, the normal differences in neuroretinal function between nondiabetic males and females under 50 years of age are altered in patients with type 2 diabetes. Furthermore, local neuroretinal function in type 2 diabetes is more abnormal in adult males compared with adult females. The literature also suggests that there are male-female differences in the occurrence of diabetes. In adolescence, the incidence of type 1 diabetes is greater in males, whereas in type 2 diabetes, the incidence is greater in females. This excess of females in type 2 diabetes shifts to a more equal incidence between the two sexes in adults. In addition, advanced retinopathy in type 1 diabetes appears to be more common in males, and the presence and severity of diabetic retinopathy at the time of diagnosis in type 2 diabetes appears to be more associated with male sex. Although the reasons for male-female differences identified in this review are unknown, sex appears to be a significant factor in certain aspects of diabetes incidence and diabetic retinopathy.

Does pregnancy accelerate the rate of progression of diabetic retinopathy?: an update

Pregnancy may be associated with several ocular changes, including the development of new ocular conditions or modifications of existing conditions. The most common ocular condition modified by pregnancy is diabetic retinopathy. Pregnancy is associated with an increased risk of development and progression of diabetic retinopathy. The factors associated with its progression include the pregnant state itself, duration of diabetes, amount of retinopathy at conception, blood glucose control, and the presence of coexisting hypertension. Although the rate of regression of diabetic retinopathy at the end of pregnancy or the postpartum period is high, careful monitoring of these patients is necessary to optimize the vision and pregnancy outcomes.

Microvascular complications and the diabetic pregnancy

Without strict glycemic control, diabetic pregnancies are frequently complicated by spontaneous abortion, stillbirth, or congenital malformation. Retrospective studies have been largely reassuring that pregnancy does not accelerate morbid outcomes in women with diabetic vascular disease. Improved outcomes of high-risk pregnancy in women with pregestational, type 1, or type 2 diabetes mellitus remain challenging, depending on a comprehensive and multidisciplinary team approach and extensive preconception counseling.

Is pregnancy a risk factor for microvascular complications? The EURODIAB Prospective Complications Study

AIMS

To examine the long-term influence of pregnancy on the development and progression of microvascular complications in Type 1 diabetes.

METHODS

In the EURODIAB Prospective Complications Study (PCS), 793 women potentially child bearing at baseline completed the follow-up (7.3 years) and 163 (21%) gave birth during the follow-up period. We compared risk factors [mean levels of age, duration of diabetes, HbA(1c), systolic blood pressure (SBP) and proportion giving birth] between those that did or did not develop microvascular complications during the follow-up period.

RESULTS

For the 425 childless women at baseline, 102 gave birth during follow-up. HbA(1c) was a significant risk factor for progression to microalbuminuria but age, duration of diabetes, systolic blood pressure or giving birth were not. Duration of diabetes and high HbA(1c) were significant risk factors for progression to proliferative retinopathy, whereas giving birth was not. Similar results were obtained for progression to any form of retinopathy. Giving birth was not significantly related to the incidence of neuropathy. Similar results were obtained for women with children at baseline giving birth during follow-up (n = 61/368).

CONCLUSIONS

In this European study, having a first or another pregnancy did not seem to be a risk factor for long-term progression of any microvascular complication. This is in accordance with the findings of the Diabetes Control and Complications Trial (DCCT).

Diabetic management in high risk patients (pregnancy, insulin pumps)

During the past decades our understanding about the clinical impact of diabetes has changed. We now know for certain that a good (read : near normal) glycemic control is necessary to prevent chronic complications of this disease in women regardless of the type of diabetes. Pregnancy is a specific situation whereby a "near normal" control is wanted not only for the patient but also for the fetus. Several studies have shown a correlation beween glycemic control and complications of pregnancy. Reaching optimal glycemic control is mandatory even before the pregnancy starts, considering the time window of occurance of the severe foetal congenital malformations (first weeks of pregnancy). The role of pre-conception care is emphasized. Optimal control in type 1 and type 2 diabetic patients can best be reached through intensive insulin therapy, but reaching normoglycemia is mainly limited by the occurence of hypoglycemia. The introduction of the new insulin analogues is an important step in our arsenal to achieve control using multiple daily insulin injections, but Novorapid and Lantus have not yet been approved for use in pregnancy. Insulin pumps are often used in pregnant patients, allowing an even better glycemic control with less hypoglycemia. An absolute requirement for CSII therapy to be successful is patient education and motivation by an experienced team.

Twenty-four-hour blood pressure monitoring in normoalbuminuric normotensive type 1 diabetic women during pregnancy

We monitored blood pressure (BP) for a 24-h period in type 1 diabetic women at each trimester of pregnancy (10-13, 20-22, and 30-33 weeks of gestation) to identify early alterations of BP profile in pregnancies complicated by hypertension.

PATIENTS AND METHODS

We prospectively studied 71 type 1 diabetic pregnant women and 48 nondiabetic pregnant women (homogeneous by age and pre-pregnancy BMI) consecutively recruited at 10+/-2 weeks of pregnancy in the space of 2 years (1999-2000). They were all normotensive (<130/80 mm Hg) and normoalbuminuric (AER<20 microg/min) at entry to the study.

STATISTICS

Analysis of variance (ANOVA) and simple regression and chi(2) were applied as appropriate by an Apple software program (Stat View).

RESULTS

In diabetic women, we recorded higher levels of diastolic BP (even if within a normal range) at each time point; diabetic vs. nondiabetic women: first trim daytime diastolic BP: 71.35+/-8.75 vs. 67.7+/-9.7, P=.01; second trim nighttime diastolic BP: 62.15+/-6.45 vs. 58.05+/-6.7, P=.05; third trim nighttime diastolic BP: 66.03+/-8.72 vs. 60.7+/-6.5, P=.01. Among diabetics, those who later developed pregnancy-induced hypertension (36.6%) showed significantly higher values of BP at the first and third trimester compared to those who remained normotensive. In the two groups, there were no differences in age and pre-pregnancy BMI by contrast of diabetes duration (hypertensive vs. normotensive, 19.18+/-7.3 vs. 14.35+/-9.1 years, P=.03) and age of diagnosis (hypertensive vs. normotensive, 9.6+/-5.5 vs. 14.7+/-8.6 years, P=.01). Positive correlation was found between fasting blood glucose and diastolic BP at each trimester of pregnancy.

Ocular changes in pregnancy

Visual changes in pregnancy are common, and many are specifically associated with the pregnancy itself. Serous retinal detachments and blindness occur more frequently during preeclampsia and often subside postpartum. Pregnant women are at increased risk for the progression of preexisting proliferative diabetic retinopathy, and diabetic women should see an ophthalmologist before pregnancy or early in the first trimester. The results of refractive eye surgery before, during, or immediately after pregnancy are unpredictable, and refractive surgery should be postponed until there is a stable postpartum refraction. A decreased tolerance to contact lenses also is common during pregnancy; therefore, it is advisable to fit contact lenses postpartum. Furthermore, pregnancy is associated with a decreased intraocular pressure in healthy eyes, and the effects of glaucoma medications on the fetus and breast-fed infant are largely unknown.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader will be able to list the various ocular changes that occur during pregnancy, summarize the ocular disturbances that occur with preeclampsia and diabetes, and describe the management of some ocular problems during pregnancy.

Does pregnancy accelerate the rate of progression of diabetic retinopathy?

Pregnancy may be associated with a number of ocular changes, including the development of new ocular conditions or modifications of existing conditions. The most common ocular condition modified by pregnancy is diabetic retinopathy. Pregnancy is associated with an increased risk of development and progression of diabetic retinopathy. The factors associated with its progression include the pregnant state itself, duration of diabetes, amount of retinopathy at conception, blood glucose control, and the presence of coexisting vascular disease. Although the rate of regression of diabetic retinopathy at the end of pregnancy or the postpartum period is high, careful monitoring of these patients is necessary to optimize both the vision and pregnancy outcomes.

Impact of pregnancy on the progression of diabetic retinopathy in Type 1 diabetes

AIMS

To evaluate the impact of pregnancy on the progression of diabetic retinopathy in women with Type 1 diabetes mellitus and to identify risk factors for the progression of retinopathy during pregnancy.

METHODS

One hundred and seventy-nine pregnancies in 139 women with pregestational Type 1 diabetes were studied prospectively between January 1990 and December 1998. Dilated fundal examination was performed at booking, 24 weeks and 34 weeks or 4-6 weekly if retinopathy present at booking. Data were collected on glycaemic control (HbA(1c)) throughout pregnancy.

RESULTS

Progression to proliferative retinopathy was seen in four (2.2%) pregnancies while moderate progression was seen in a further five (2.8%) pregnancies. Progression of retinopathy was significantly increased in women with duration of diabetes 10-19 years compared with duration < 10 years (10% vs. 0%; P = 0.007) and in women with moderate to severe background retinopathy at booking (30% vs. 3.7%; P = 0.01). Although HbA(1c) at booking was higher (7.5% vs. 6.6%; P = 0.08) and the fall in HbA(1c) between booking and 24 weeks was greater (1.6% vs. 1.2%; P = 0.2) in those women showing progression of retinopathy, these changes were not significant.

CONCLUSIONS

Progression of retinopathy in pregnancy was uncommon (5.0% pregnancies) but was significantly more common in women with duration of diabetes > 10 years and in women with moderate to severe retinopathy at baseline. Laser therapy was needed in 2.2% pregnancies, which is much lower than that reported in earlier studies. Diabet. Med. 18, 573-577 (2001)

Effect of pregnancy on microvascular complications in the diabetes control and complications trial. The Diabetes Control and Complications Trial Research Group

OBJECTIVE

To assess the effect of pregnancy on the development and progression of retinopathy and microalbuminuria in type 1 diabetes.

RESEARCH DESIGN AND METHODS

We conducted longitudinal analyses of the Diabetes Control and Complications Trial (DCCT), a multicenter controlled clinical trial that compared intensive treatment with conventional diabetes therapy and studied 180 women who had 270 pregnancies and 500 women who did not become pregnant during an average of 6.5 years of follow-up. Women assigned to the conventional treatment group were changed to intensive therapy if they were planning pregnancy or as soon as possible after conception. Fundus photography was performed every 6 months, and the urinary albumin excretion rate (AER) was measured annually.

RESULTS

Compared with nonpregnant women, pregnant women had a 1.63-fold greater risk of any worsening of retinopathy from before to during pregnancy (P < 0.05) in the intensive treatment group; the risk was 2.48-fold greater for pregnant vs. not pregnant women in the conventional group (P < 0.001). In the conventional group, the odds of > or =3-step progression from the baseline retinopathy level was >2.9-fold among pregnant vs. not pregnant women (P = 0.003). The odds ratio (OR) peaked during the second trimester (OR = 4.26, P = 0.001) and persisted as long as 12 months postpregnancy (OR = 2.87, P = 0.005). The level of AER during pregnancy in the intensive group, but not in the conventional group, was significantly elevated from the level at baseline, albeit in the normal range. Although individual patients had transient worsening of retinopathy during pregnancy, even to the proliferative level, at the end of the DCCT, mean levels of retinopathy and albuminuria in subjects who had become pregnant were similar to those in subjects who had not become pregnant within each treatment group.

CONCLUSIONS

Pregnancy in type 1 diabetes induces a transient increase in the risk of retinopathy; increased ophthalmologic surveillance is needed during pregnancy and the first year postpartum. The long-term risk of progression of early retinopathy and albumin excretion, however, does not appear to be increased by pregnancy.

Medical complications of diabetes mellitus in pregnancy

Many women with diabetes develop complications of their chronic disease that may have a tremendous impact on their quality of life and their ultimate prognosis. Because Type 1 diabetes often begins at a very early age, it is quite common for women in their child-bearing years to be affected by these complications. As described in this article, diabetic complications and pregnancy may significantly affect each other, but it is not always easy to predict the course of either and to counsel these patients accordingly. Nevertheless, it appears that only in rare occasions should women with diabetes be advised against pregnancy, and that in most situations, with careful and knowledgeable management, a favorable outcome of pregnancy can be expected both for the mother and her infant.