Impact of gestational diabetes mellitus diagnosed during the third trimester on pregnancy outcomes: a case-control study

Abstract

Background In 2010, the International Association of Diabetes and Pregnancy Study Group (IADPSG) proposed new criteria indicating that gestational diabetes mellitus (GDM) can be diagnosed if the fasting threshold of ≤92 mg/dL, 1-h threshold of ≤180 mg/dL, or 2-h threshold of ≤153 mg/dL are exceeded during the 75-g 2-h oral glucose tolerance test (OGTT) performed at 24–28 weeks of gestation. The World Health Organization (WHO) recommends using the proposed diagnostic threshold values of the IADPSG to diagnose GDM; however, it does not limit the timing of the 75-g OGTT. Since 2010 in Japan, GDM has been diagnosed using the same criteria as that proposed by the WHO. However, neither the JSOG nor the WHO has provided any evidence that it is appropriate to use a threshold beyond the range recommended by the IADPSG. Methods This was a single-centre retrospective study based on the medical records and delivery registry database of our centre. We included women who underwent a 50-g glucose challenge test (GCT) with results < 140 mg/dL at 24–28 weeks of gestation and subsequently underwent a 75-g OGTT after 29 weeks of gestation with abnormal glucose tolerance suspected based on clinical findings. The reference values for the 75-g OGTT followed the IADPSG criteria. Subjects were classified into the normal glucose tolerance (NGT) group and the GDM group. The type of delivery and neonatal outcomes of the two groups were compared. A multivariable analysis was performed to match the backgrounds of both groups. Results In total, the NGT and GDM group comprised 189 and 49 women, respectively. Emergency caesarean delivery rates were similar in the GDM and NGT groups (10.6 and 12.2%, respectively; adjusted odds ratio [OR], 1.25; 95% confidence interval [CI], 0.43–3.64; p = 0.74); however, the elective caesarean delivery rate was higher in the GDM group than in the NGT group (16.3 and 5.3%, respectively, adjusted OR, 3.60; 95% CI, 1.27–10.19; p = 0.01). No significant differences were observed in other maternal and neonatal outcomes between both groups. Conclusion Although a diagnosis of GDM during the third trimester does not improve pregnancy outcomes, it increases the elective caesarean delivery rate.

The impact on pregnancy outcomes of late‐onset gestational diabetes mellitus diagnosed during the third trimester: A systematic review and meta‐analysis

“…[17][18][19]23,24 Heterogeneity of population characteristics was considerable between the studies. This was evident by the inclusion in several studies, of women with polyhydramnios, 10,19,21,22,24 suspected LGA/macrosomia, 10,17,[20][21][22]24 glycosuria, 10 and risk factors for GDM such as obesity and family history of diabetes. 16,24,25 The characteristics of the studies included are shown in Table 1.…”

“…The 12 studies that were selected for the meta-analysis included 3103 women and 3674 pregnancies (571 pregnancies with late GDM and 3103 pregnancies without late GDM) (Figure 1). 9,10,[16][17][18][19][20][21][22][23][24][25] Table S4 presents the quality and risk of bias assessment of the included studies. 14 Eleven of the F I G U R E 2 Forest plots and summary of odds ratios of associations between late gestational diabetes and perinatal outcomes.…”

Third trimester re‐screening for gestational diabetes in morbidly obese women despite earlier negative test can reveal risks for obstetrical complications

“…[11][12][13] Usually, late OGTT is performed based on clinical findings such as polyhydramnios or a suspected LGA fetus. 13,14 A recent study reported a late GDM diagnosis rate of 22% (>29 weeks), of whom 36.8% were with third trimester BMI > 30 kg/m 2.12 Another study showed associations of abnormal nearterm OGTT with both maternal and neonatal complications, and recommended that late third-trimester OGTT should be considered for the subset of women with suspected LGA fetuses or polyhydramnios. 15,16 However, only a few studies controlled for BMI in the late third trimester and examined its association with late GDM diagnosis.…”

“…Recent studies have investigated the implications of late GDM diagnosis (>29 weeks) 11–13 . Usually, late OGTT is performed based on clinical findings such as polyhydramnios or a suspected LGA fetus 13,14 . A recent study reported a late GDM diagnosis rate of 22% (>29 weeks), of whom 36.8% were with third trimester BMI > 30 kg/m 2.…”

Associations of morbid obesity with late diagnosis of gestational diabetes, and with related obstetrical and neonatal outcomes

“…Recent studies have investigated the implications of late GDM diagnosis [14][15][16], when an oral glucose tolerance test (OGTT) is performed beyond the recommended 24-28 weeks gestation. Usually, late OGTT is performed based on clinical ndings such as polyhydramnios or a suspected LGA fetus [16][17]. A recent study reported a late GDM diagnosis rate of 22% (> 29 weeks), of whom 36.8% were with BMI > 30 kg/m 2 [15].…”