Advances in gestational diabetes mellitus screening: Emerging trends and future directions

Table 1 Risk factors for gestational diabetes mellitus

Risk factors
Overweight or obese adults (BMI ≥ 25 kg/m2, ≥ 23 kg/m2 for Asians) with at least one of the following risk factors:
History of diabetes in a first-degree relative
High-risk race or ethnicity (e.g., African American, Latin American)
History of cardiovascular disease
HDL cholesterol level < 35 mg/dL (< 0.9 mmol/L) and/or triglyceride level > 250 mg/dL (> 2.8 mmol/L)
Polycystic ovary syndrome
Physical inactivity
Other clinical conditions associated with insulin resistance (obesity, acanthosis nigricans)
Prediabetes (HbA1c ≥ 5.7%) and impaired fasting and glucose tolerance
Individuals previously diagnosed with GDM
Individuals afflicted with HIV, those utilizing medications that elevate the risk of diabetes, and those with a history of pancreatitis. Additionally, ACOG:
History of birth over 4000 g
Hypertension (140/90 mmHg or those taking antihypertensive medication)

Risk factors for gestational diabetes mellitus[5]. BMI: Body mass index; HDL: High density lipoprotein; GDM: Gestational diabetes mellitus; ACOG: American College of Obstetricians and Gynecologists; HIV: Human immunodeficiency virus; HbA1c: Glycated hemoglobin.

Table 2 Maternal and fetal complications of gestational diabetes mellitus

	Maternal	Fetal
Short term	Preeclampsia	Macrosomia
	Preterm delivery	Shoulder dystocia
	Caesarean section	Perinatal mortality
	Failure to progress in labour and instrumental delivery	Admission to NICU
		Neonatal hypoglycaemia
		Hyperbilirubinaemia
Long term	Recurrent GDM in subsequent pregnancies	Type 2 diabetes
	Type 2 diabetes	Obesity
	Cardiovascular disease

Maternal and fetal complications of gestational diabetes mellitus[6,7]. GDM: Gestational diabetes mellitus; NICU: Neonatal intensive care unit.

Table 3 Screening and diagnosis of gestational diabetes mellitus

	One-step strategy	Two-step strategy
Test	75 g OGTT: In individuals without a prior diagnosis of diabetes, screening is performed in the fasting state between 24 and 28 weeks of gestation (following a minimum of 8 hours of overnight fasting). GDM is diagnosed if any of the following blood glucose thresholds are met or exceeded	First step: 50 g glucose challenge test: This test is administered between 24 and 28 weeks of gestation in individuals without a prior diagnosis of diabetes and does not require fasting. If the 1-hour plasma glucose level meets or exceeds the specified threshold values, a 100 g OGTT should be performed
Blood glucose thresholds	IADPSG: Fasting glucose ≥ 93 mg/dL (≥ 5.1 mmol/L)	Fasting glucose ≥ 95 mg/dL (≥ 5.3 mmol/L)
	1-hour plasma glucose ≥ 180 mg/dL (≥ 10.0 mmol/L)	1-hour plasma glucose ≥ 180 mg/dL (≥ 10.0 mmol/L)
	2-hour plasma glucose ≥ 153 mg/dL (≥ 8.5 mmol/L)	2-hour plasma glucose ≥ 155 mg/dL (≥ 8.6 mmol/L)
	Carpenter-Coustan criteria: Fasting glucose ≥ 95 mg/dL (≥ 5.3 mmol/L)	2-hour plasma glucose ≥ 140 mg/dL (≥ 7.8 mmol/L)
	1-hour plasma glucose ≥ 180 mg/dL (≥ 10.0 mmol/L)
	2-hour plasma glucose ≥ 155 mg/dL (≥ 8.6 mmol/L)

Screening and diagnosis of gestational diabetes mellitus[8]. IADPSG: International Association of Diabetes and Pregnancy Study Groups; OGTT: Oral glucose tolerance test; GDM: Gestational diabetes mellitus.

Table 4 Gestational diabetes mellitus screening strategies recommended by various international organizations

Guide	Strategy
ADA	75 g OGTT for all pregnant women
ACOG	Administer a 50 g GCT for all pregnant women; a 100 g OGTT is required if the initial test is positive
WHO	75 g OGTT for all pregnant women
NICE	75 g OGTT risk-based approach
FIGO	75 g OGTT for all pregnant women

Gestational diabetes mellitus screening strategies recommended by various international organizations[5,8,23,24]. ACOG: American College of Obstetricians and Gynecologists; NICE: National Institute for Health and Care Excellence; FIGO: International Federation of Gynecology and Obstetrics; WHO: World Health Organization; ADA: American Diabetes Association; OGTT: Oral glucose tolerance test; GCT: Glucose challenge test.