Impact of new International Association of Diabetes and Pregnancy Study Groups (IADPSG) diagnostic criteria on perinatal outcomes in a regional tertiary hospital in New South Wales, Australia

Gestational diabetes mellitus and adverse pregnancy outcomes: systematic review and meta-analysis

OBJECTIVE

To investigate the association between gestational diabetes mellitus and adverse outcomes of pregnancy after adjustment for at least minimal confounding factors.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Web of Science, PubMed, Medline, and Cochrane Database of Systematic Reviews, from 1 January 1990 to 1 November 2021.

REVIEW METHODS

Cohort studies and control arms of trials reporting complications of pregnancy in women with gestational diabetes mellitus were eligible for inclusion. Based on the use of insulin, studies were divided into three subgroups: no insulin use (patients never used insulin during the course of the disease), insulin use (different proportions of patients were treated with insulin), and insulin use not reported. Subgroup analyses were performed based on the status of the country (developed or developing), quality of the study, diagnostic criteria, and screening method. Meta-regression models were applied based on the proportion of patients who had received insulin.

RESULTS

156 studies with 7 506 061 pregnancies were included, and 50 (32.1%) showed a low or medium risk of bias. In studies with no insulin use, when adjusted for confounders, women with gestational diabetes mellitus had increased odds of caesarean section (odds ratio 1.16, 95% confidence interval 1.03 to 1.32), preterm delivery (1.51, 1.26 to 1.80), low one minute Apgar score (1.43, 1.01 to 2.03), macrosomia (1.70, 1.23 to 2.36), and infant born large for gestational age (1.57, 1.25 to 1.97). In studies with insulin use, when adjusted for confounders, the odds of having an infant large for gestational age (odds ratio 1.61, 1.09 to 2.37), or with respiratory distress syndrome (1.57, 1.19 to 2.08) or neonatal jaundice (1.28, 1.02 to 1.62), or requiring admission to the neonatal intensive care unit (2.29, 1.59 to 3.31), were higher in women with gestational diabetes mellitus than in those without diabetes. No clear evidence was found for differences in the odds of instrumental delivery, shoulder dystocia, postpartum haemorrhage, stillbirth, neonatal death, low five minute Apgar score, low birth weight, and small for gestational age between women with and without gestational diabetes mellitus after adjusting for confounders. Country status, adjustment for body mass index, and screening methods significantly contributed to heterogeneity between studies for several adverse outcomes of pregnancy.

CONCLUSIONS

When adjusted for confounders, gestational diabetes mellitus was significantly associated with pregnancy complications. The findings contribute to a more comprehensive understanding of the adverse outcomes of pregnancy related to gestational diabetes mellitus. Future primary studies should routinely consider adjusting for a more complete set of prognostic factors.

REVIEW REGISTRATION

PROSPERO CRD42021265837.

Effect of interventions in pregnant women with mildly impaired glucose tolerance

AIM

In 2010, the Japan Society of Obstetrics and Gynecology (JSOG) changed the diagnostic criteria for gestational diabetes mellitus (GDM) to follow the International Association of Diabetes and Pregnancy Study Group (IADPSG) criteria. As a result, many pregnant women with mildly impaired glucose tolerance (IGT) were newly diagnosed with GDM. This study aimed to verify the effects of interventions in pregnant women with mild IGT who were newly diagnosed with GDM based on the present JSOG criteria.

METHODS

We defined mild IGT as a degree of IGT that would be diagnosed as GDM according to the present but not the previous JSOG criteria. We compared pregnancy and delivery outcomes in women with mild IGT who delivered a singleton at 22 weeks of gestation or later, between 2000 and 2009 (untreated group, n = 503) versus between 2011 and 2017 (treated group, n = 781).

RESULTS

The incidence of GDM-related composite complications such as macrosomia, shoulder dystocia, neonatal hypoglycemia, neonatal hyperbilirubinemia, and neonatal respiratory distress syndrome was comparable in the untreated and treated groups (10.1% vs. 11.9%, p = 0.11). The pregnancy outcomes were also comparable, except for infant birth weights, which were lower in the treated group than in the untreated group (3014 g vs. 3094 g; p = 0.02).

CONCLUSIONS

Pregnancy outcomes were not affected by the interventions in pregnant women with mild IGT.

Impact of introducing the International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria on pregnancy outcomes in Japan

To estimate pregnancy complications in women newly diagnosed with gestational diabetes mellitus (GDM) according to the new International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria and verify the validity of introducing the IADPSG criteria in Japan. This retrospective study included data from women with singleton delivery at 22 weeks or later at a tertiary hospital during 2000-2009. We compared pregnancy outcomes between women who would now be diagnosed with GDM according to the IADPSG criteria but not by the old JSOG criteria (IGT group, n = 503) and women with normal glucose tolerance according to both the criteria (NGT group, n = 2,789). Multivariate analysis was performed and adjusted for background factors. Maternal age at delivery and pre-pregnancy BMI were significantly higher in the IGT group than in the NGT group, while gestational weeks at delivery did not differ between the groups. No difference was observed in the rates of GDM-related composite complications (defined as cases with at least one of the following: macrosomia, shoulder dystocia, neonatal hypoglycemia, neonatal hyperbilirubinemia, or neonatal respiratory distress syndrome) at 11.9% and 8.8% (adjusted odds ratio (OR) 1.30, 95% confidence interval (CI) 0.90-1.87, p = 0.16). Pregnancy outcomes did not differ significantly between the IGT and NGT groups, except for frequencies of total neonatal admissions at 10.5% and 7.1%, respectively (adjusted OR 1.55, 95% CI 1.12-2.13, p < 0.01).

The impact of diagnostic criteria for gestational diabetes on its prevalence: a systematic review and meta-analysis

BACKGROUND

The absence of universal gold standards for screening of gestational diabetes (GDM) has led to heterogeneity in the identification of GDM, thereby impacting the accurate estimation of the prevalence of GDM. We aimed to evaluate the effect of different diagnostic criteria for GDM on its prevalence among general populations of pregnant women worldwide, and also to investigate the prevalence of GDM based on various geographic regions.

METHODS

A comprehensive literature search was performed in PubMed, Scopus and Google-scholar databases for retrieving articles in English investigating the prevalence of GDM. All populations were classified to seven groups based-on their diagnostic criteria for GDM. Heterogeneous and non-heterogeneous results were analyzed using the fixed effect and random-effects inverse variance model for calculating the pooled effect. Publication bias was assessed by Begg's test. The Meta-prop method was used for the pooled estimation of the prevalence of GDM. Meta-regression was conducted to explore the association between prevalence of GDM and its diagnostic criteria. Modified Newcastle-Ottawa Quality Assessment Scale for nonrandomized studies was used for quality assessment of the studies included; the ROBINS and the Cochrane Collaboration's risk of bias assessment tools were used to evaluate the risk of bias.

RESULTS

We used data from 51 population-based studies, i.e. a study population of 5,349,476 pregnant women. Worldwide, the pooled overall-prevalence of GDM, regardless of type of screening threshold categories was 4.4%, (95% CI 4.3-4.4%). The pooled overall prevalence of GDM in the diagnostic threshold used in IADPSG criteria was 10.6% (95% CI 10.5-10.6%), which was the highest pooled prevalence of GDM among studies included. Meta-regression showed that the prevalence of GDM among studies that used the IADPSG criteria was significantly higher (6-11 fold) than other subgroups. The highest and lowest prevalence of GDM, regardless of screening criteria were reported in East-Asia and Australia (Pooled-P = 11.4%, 95% CI 11.1-11.7%) and (Pooled-P = 3.6%, 95% CI 3.6-3.7%), respectively.

CONCLUSION

Over the past quarter century, the diagnosis of gestational diabetes has been changed several times; along with worldwide increasing trend of obesity and diabetes, reducing the threshold of GDM is associated with a significant increase in the incidence of GDM. The harm and benefit of reducing the threshold of diagnostic criteria on pregnancy outcomes, women's psychological aspects, and health costs should be evaluated precisely.