Table 1. Study characteristics of diabetic and non-diabetic pregnant women included in the study.

Authors	Year of publication	Country	Study Settings	Study design	BMI (Kg/m2)		Trimester of pregnancy	# Cases/controls	Sample	Level of AGEs (AU/mL)
										GDM	Controls
										Mean ±SD or Mean [95% CI]	Mean ±SD or Mean [95% CI]
					GDM	Controls
					Mean ±SD	Mean ±SD
Aziz et al [37]	2015	Iraq	Hospitals in Baghdad	Case-control	28.80±0.27	27.77±0.40	Third	30/30	Blood	5.29±0.28	2.76±0.33
Bartakova et al [30]	2016	Czek	Hospital of Brno	Case-control	24.80 ± 1.76	21.15± 1.73	Second	182/36	Blood	10.18 [8.09–12.22]	5.73 [5.29–8.66]
Boutzios et al [31]	2013	Greece	Aretaieion University Hospital, Athens	Cross-sectional	30.3 ± 4.4	27.9 ± 3.1	Second	54/56	Blood	7.28 ± 2.4	5.68 ± 1.3
Cosson et al [32]	2019	France	Jean-Verdier hospital, Paris	Case-control	NR	NR	Second	48/70	Skin	1.99 ± 0.47	1.79 ± 0.32
							First	62/70		2.11 ± 0.48
Davison et al [33]	2011	UK	Royal Liverpool University Hospital	Case-control	NR	NR	Third	15/29	Blood	3.58±0.83	3.13±0.51
de Ranitiz-Greven et al [34]	2012	Netherlands	University Medical Center Utrecht	Cross sectional	27.6 ± 6.0	25.0 ± 6.3	Second	60/44	Skin	1.73 ± 0.33	1.81± 0.30
Harsem et al [35]	2008	Norway	Ulleval University Hospital.	Case-control	32.1 ± 4.33	28.5 ± 4.89	Third	34/38	Blood	1.72 (1.47–1.91)	1.28 (1.13–1.42)
Krishnasamy et al [39]	2019a	India	Tertiary referral centers in Tamil Nadu	Case-control	25.72 ± 5.48	24.22 ± 4.67	Third	50/50	Blood	13.18 ± 8.74	2.68 ± 0.89
Krishnasamy et al [40]	2019b	India	Two tertiary care hospitals	Case-control	26.36 ± 0.61	26.27 ± 0.25	Third	50/50	Blood	10.40 ± 0.98	4.71 ± 0.39
Li et al [41]	2019	China	Binzhou City Center Hospital	Case-control	23.17±3.16	22.86±2.66	Second	72/80	Placenta	54.27±18.28	32.18±12.12
Li and Yang [42]	2019	China	Peking University First Hospital	Case-control	22.71 ± 3.20	21.65 ± 2.84	Second	90/90	Blood	473.65 ± 105.32	324.36 ± 57.86 (ng/L)*
							Third	90/90	Blood	533.47 ± 146.95	315.50 ± 77.79 (ng/L)*
Lobo et al [44]	2017	Brazil	NS	Case-control	32.0 ± 2.22	25.4 ± 1.48	Second	225/217	Blood	2.42 ± 0.72	2.50 ± 0.86
Pertyn´ska-Marczewska [36]	2009	Poland	Polish Mother’s Memorial Hospital	Case-control	24.25 ± 2.57	23.17 ± 4.43	First	14/14	Blood	9.5 ± 1.9	5.2 ± 1.3
					NR	NR	Third	14/14	Blood	9.7 ± 1.9	5.3 ± 0.7
Guosheng et al [38]	2009	China	First Affiliated Hospital of Jinan University	Case-control	NR	NR	Second	60/72	Blood	8.114±2.375	4.262±1.284
							Third	72/80	Blood	8.085±2.396	4.830±1.156
Mai et al [43]	2014	China	Guangdong Women and Children Hospital	Case-control	22.7±3.5	21.5±2.7	NS	190/80	Blood	403.0+ 208.6	321.8 +150.3 (ng/L) *
Morales et al [45]	2016	Mexico	Regional general hospital	Cross-sectional	33.99±5.32	30.09±4.02	NS	38/38	Blood	NR	NR

NS, not specified; NR, not recorded; SD, standardized difference

*measurements in units other than specified one. NB: Studies reported in 95% CI were converted to SD using STATA 15.0 for the sake of analysis.