HbA1c as screening for gestational diabetes mellitus in women with polycystic ovary syndrome

Gestational Diabetes Mellitus in the Setting of Polycystic Ovarian Syndrome: A Systematic Review

Gestational diabetes mellitus (GDM) is the most common complication of pregnancy that arises in the 2nd and 3rd trimesters, leading to significant complications for the mother and her neonates, such as an increased rate of pregnancy-induced hypertension and miscarriages, while neonates may have a large birth weight, hypoglycemia, or macrosomnia. Numerous risk factors can lead to GDM; however, a significant one is polycystic ovarian syndrome (PCOS). PCOS is the most common endocrine pathology beginning before puberty, and due to significant hormonal changes, it is not diagnosed until after puberty. PCOS requires at least three of the following symptoms: hyperandrogenism, menstrual irregularities, or polycystic ovary morphology. While it is agreed that women with PCOS are at a significantly increased risk of GDM, no publication to our knowledge has evaluated the full relationship of GDM in the setting of PCOS. This paper aimed to assess this relationship and determine how it may differ for pregnant women with only GDM by determining the prevalence of GDM, the variations within phenotypes, the influence of fertilization methods, specific risk factors, maternal outcomes, and neonatal outcomes. The prevalence of GDM was significantly increased in women with PCOS compared to healthy controls, and some studies have found that phenotype A may be more likely to lead to GDM. Risk factors were similar to pregnant women with only GDM, but with GDM and PCOS specifically, preconception low sex hormone-binding globulin, increased BMI > 25 kg/m2, and preconception impaired glucose tolerance were specific. While maternal outcomes were similar to pregnant women with only GDM, women with GDM and PCOS were even more likely to develop pregnancy-induced hypertension and early miscarriage. Neonates from mothers with GDM and PCOS were more likely to have low birth weights compared to mothers with just GDM who had high birth weights. The evaluation of the relationship between GDM and PCOS allows for illumination of the need to evaluate influences that currently lack research, such as phenotype variation and influences of fertilization method. This also promotes the need to develop predictive algorithms based on risk factors to prevent these adverse outcomes for mothers and neonates.

Gestational Diabetes Mellitus and Preeclampsia: Correlation and Influencing Factors

Gestational diabetes mellitus (GDM) and preeclampsia (PE) are common pregnancy complications with similar risk factors and pathophysiological changes. Evidence from previous studies suggests that the incidence of PE is significantly increased in women with GDM, but whether GDM is independently related to the occurrence of PE has remained controversial. GDM complicated by PE further increases perinatal adverse events with greater impact on the future maternal and offspring health. Identify factors associated with PE in women with GDM women, specifically those that are controllable, is important for improving pregnancy outcomes. This paper provides the findings of a review on the correlation between GDM and PE, factors associated with PE in women with GDM, possible mechanisms, and predictive markers. Most studies concluded that GDM is independently associated with PE in singleton pregnancy, and optimizing the treatment and management of GDM can reduce the incidence of PE, which is very helpful to improve pregnancy outcomes.

Prediabetes and pregnancy: Early pregnancy HbA1c identifies Australian Aboriginal women with high-risk of gestational diabetes mellitus and adverse perinatal outcomes

AIMS

To assess whether early pregnancy HbA_1c can predict gestational diabetes mellitus (GDM) and adverse birth outcomes in Australian women.

METHODS

Prospective study of 466 women without diabetes, aged ≥16-years at first antenatal presentation. Recruitment was from 27 primary healthcare sites in rural and remote Australia from 9-January 2015 to 31-May 2018. HbA_1c was measured with first antenatal investigations (<20-weeks gestation). Primary outcome measure was predictive value of HbA_1c for GDM, by routine 75 g oral glucose tolerance test (OGTT; ≥24-weeks gestation), and for large-for-gestational-age (LGA) newborn.

RESULTS

Of 396 (129 Aboriginal) women with routine OGTT, 28.8% had GDM (24.0% Aboriginal). HbA_1c ≥5.6% (≥38 mmol/mol) was highly predictive (71.4%, 95% CI; 47.8-88.7%) for GDM in Aboriginal women, and in the total cohort increased risk for LGA newborn (RR 2.04, 95% CI; 1.03-4.01, P = 0.040). There were clear differences between Aboriginal and non-Aboriginal women: 16.3% v 5.2% (P < 0.001) had elevated HbA_1c whereas 12.4% v 29.6% (P < 0.001) developed hyperglycemia during pregnancy.

CONCLUSIONS

Early pregnancy HbA_1c ≥5.6% (≥38 mmol/mol) identifies Aboriginal women with apparent prediabetes and elevated risk of having an LGA newborn. Universal HbA_1c at first antenatal presentation could facilitate earlier management of hyperglycemia and improved perinatal outcome in this high-risk population.

The accuracy of haemoglobin A1c as a screening and diagnostic test for gestational diabetes: a systematic review and meta-analysis of test accuracy studies

PURPOSE OF REVIEW

Gestational diabetes mellitus (GDM) is associated with adverse pregnancy complications. Accurate screening and diagnosis of gestational diabetes are critical to treatment, and in a pandemic scenario like coronavirus disease 2019 needing a simple test that minimises prolonged hospital stay. We undertook a meta-analysis on the screening and diagnostic accuracy of the haemoglobin A1c (HbA1c) test in women with and without risk factors for gestational diabetes.

RECENT FINDINGS

Unlike the oral glucose tolerance test, the HbA1c test is simple, quick and more acceptable. There is a growing body of evidence on the accuracy of HbA1c as a screening and diagnostic test for GDM. We searched Medline, Embase and Cochrane Library and selected relevant studies. Accuracy data for different thresholds within the final 23 included studies (16 921 women) were pooled using a multiple thresholds model. Summary accuracy indices were estimated by selecting an optimal threshold that optimises either sensitivity or specificity according to different scenarios.

SUMMARY

HbA1c is more useful as a specific test at a cut-off of 5.7% (39 mmol/mol) with a false positive rate of 10%, but should be supplemented by a more sensitive test to detect women with GDM.

Does serum hemoglobin A1C during early pregnancy predict performance on the 1-hour glucose challenge test?

PURPOSE

To determine the negative and positive predictive values of hemoglobin A1c (HgbA1c) levels in predicting abnormal 1-hour glucose challenge test (GCT) results in pregnancy.

METHODS

This retrospective cohort study consisted of pregnant patients from a private practice obstetrics clinic. The primary exposure was early HgbA1c measurement, and the primary outcome was third trimester 1-hour GCT results above or below 140 mg/dL. We calculated the predictive value of early HgbA1c to identify a 1-hour GCT of ≤140 mg/dL or >140 mg/dL.

RESULTS

Of the 1404 one-hour GCT results, 635 were associated with HgbA1c being measured in a patient on the same day or before the 1-hour GCT. The median interval between the HgbA1c test and the 1-hour GCT was 95 days (IQR 56-122 days). Among women with a hgbA1c less than or equal to 4.9, 5.0 and 5.1, respectively, the probability of their 1 hour GCT being 140 mg/dl or less was 91.3%, 91.0% and 90.1%, respectively (Table 1). Among our study population, 14.5%, 22.8% and 35.0% had an Hgb A1c less than or equal to 4.9, 5.0 and 5.1 respectively. Among women with HgbA1c greater than 6.1, the probability of their 1-hour GCT being greater than 140 mg/dL was 100%. Only 0.3% of our population had HgbA1c greater than 6.1. There was no other cut point for HgbA1c, where the positive predictive value for predicting an abnormal 1-hour GCT was equal to or greater than 90%.

CONCLUSIONS

The greatest value of an early HgbA1C test appears to be that very low values (5.1 or less) can predict a normal 1 h GCT with high probability (at least 90%). However, it has limited ability to predict abnormal 1 h GCT. Overall, an early HgbA1C cannot replace the 1 h GCT based on the current body of evidence.

Polycystic ovary syndrome and hyperglycaemia in pregnancy. A narrative review and results from a prospective Danish cohort study

BACKGROUND

Insulin resistance is common in polycystic ovary syndrome (PCOS). PCOS may be associated with increased risk of gestational diabetes mellitus (GDM).

OBJECTIVES

To (1) review literature regarding PCOS and hyperglycaemia in pregnancy and (2) present original data from Odense Child Cohort (OCC) regarding GDM in PCOS.

METHODS

Literature search including original studies from 2000-18. OCC included 2548 pregnant women, 9.5% (n = 241) had PCOS. Fasting plasma glucose was measured in 1519 and 659 oral glucose tolerance tests were performed (with risk factor for GDM, n = 384, without risk factors, n = 275), applying two different GDM criteria.

RESULTS

30 studies were eligible using 12 different sets of diagnostic criteria for GDM. Ten studies included n > 50, control group, assessment of GDM and BMI. Results were not uniform, but supported that higher BMI, higher age, Asian ethnicity, and fertility treatment increased the risk of GDM in PCOS. In OCC, women with PCOS and controls had similar prevalences of GDM independent of different sets of criteria for GDM.

CONCLUSION

PCOS may not be an individual risk factor for GDM. Pregnancies in PCOS are characterized by factors known to increase risk of GDM, especially high BMI and fertility treatment.

Associations of mid-pregnancy HbA1c with gestational diabetes and risk of adverse pregnancy outcomes in high-risk Taiwanese women

BACKGROUND

The objective of this study was to investigate the associations among the mid-pregnancy glycated hemoglobin A1c (HbA1c) level, gestational diabetes (GDM), and risk of adverse pregnancy outcomes in women without overt diabetes and with positive 50-g, 1-h glucose challenge test (GCT) results (140 mg/dL or greater).

METHODS

This prospective study enrolled 1,989 pregnant Taiwanese women. A two-step approach, including a 50-g, 1-h GCT and 100-g, 3-h oral glucose tolerance test (OGTT), was employed for the diagnosis of GDM at weeks 23-32. The mid-pregnancy HbA1c level was measured at the time the OGTT was performed. A receiver operating characteristic (ROC) curve was used to determine the relationship between the mid-pregnancy HbA1c level and GDM. Multiple logistic regression models were implemented to assess the relationships between the mid-pregnancy HbA1c level and adverse pregnancy outcomes.

RESULTS

An ROC curve demonstrated that the optimal mid-pregnancy HbA1c cut-off point to predict GDM, as diagnosed by the Carpenter-Coustan criteria using a two-step approach, was 5.7%. The area under the ROC curve of the mid-pregnancy HbA1c level for GDM was 0.70. Compared with the levels of 4.5-4.9%, higher mid-pregnancy HbA1c levels (5.0-5.4, 5.5-5.9, 6.0-6.4, 6.5-6.9, and >7.0%) were significantly associated with increased risks of gestational hypertension or preeclampsia, preterm delivery, admission to the neonatal intensive care unit, low birth weight, and macrosomia (the odds ratio [OR] ranges were 1.20-9.98, 1.31-5.16, 0.88-3.15, 0.89-4.10, and 2.22-27.86, respectively).

CONCLUSIONS

The mid-pregnancy HbA1c level was associated with various adverse pregnancy outcomes in high-risk Taiwanese women. However, it lacked adequate sensitivity and specificity to replace the two-step approach in the diagnosis of GDM. The current study comprised a single-center prospective study; thus, additional, randomized control design studies are required.

Early Pregnancy Biochemical Predictors of Gestational Diabetes Mellitus

PURPOSE OF REVIEW

Universal oral glucose tolerance-based screening is employed to identify pregnant women with gestational diabetes mellitus (GDM), as treatment of this condition decreases the risk of associated complications. A simple and accurate blood test which identifies women at low or high risk for GDM in the first trimester would have the potential to decrease costs and improve outcomes through prevention or treatment. This review summarizes published data on early pregnancy biomarkers which have been tested as predictors of GDM.

RECENT FINDINGS

A large number of first-trimester biochemical predictors of GDM have been reported, mostly in small case-control studies. These include glycemic markers (fasting glucose, post-load glucose, hemoglobin A1C), inflammatory markers (C-reactive protein, tumor necrosis factor-alpha), insulin resistance markers (fasting insulin, sex hormone-binding globulin), adipocyte-derived markers (adiponectin, leptin), placenta-derived markers (follistatin-like-3, placental growth factor, placental exosomes), and others (e.g., glycosylated fibronectin, soluble (pro)renin receptor, alanine aminotransferase, ferritin). A few large studies suggest that first-trimester fasting glucose or hemoglobin A1C may be useful for identifying women who would benefit from early GDM treatment. To translate the findings from observational studies of first-trimester biomarkers for GDM to clinical practice, trials or cost-effectiveness analyses of screening and treatment strategies based on these novel biomarkers are needed.

A Review on Glycosylated Hemoglobin in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is one of the most common reproductive endocrine disorders among women of reproductive age, with a variety of complications and consequences mostly due to hyperandrogenism and insulin resistance (IR). PCOS patients with IR are at risk for metabolic syndrome and diabetes mellitus (DM) along with its complications such as cardiovascular events. There are several methods for screening IR in patients with PCOS to predict DM and other complications. Fasting plasma glucose test, oral glucose tolerance test, and insulin and glycosylated hemoglobin (HbA1c) levels are some available screening tools for IR. The American Diabetes Association recommended HbA1c to screen for DM because HbA1c is not affected by day-to-day plasma glucose levels and reflects the plasma glucose status during 2-3 months before measurement. Some studies have evaluated the role of HbA1c as a screening method to predict DM in PCOS patients, however, there are still controversies in this matter. Also some studies reported that HbA1c has a correlation with complications of PCOS such as metabolic syndrome and cardiovascular events. We found that HbA1c could be a suitable screening test for IR in PCOS patients but more studies are recommended, omitting confounding factors that could affect IR in patients with PCOS, such as antihyperglycemic agents like metformin, or lifestyle modification, which can be effective in reducing IR in patients with PCOS.