Table 1 Summary of studies assessing GDM prevalence in women PCOS and controls with or without metformin therapy

Abd El Hameed et al. (2011)¹

Rotterdam

Time: 8,24,36 w, guideline: NM°

N = 31, Age: 30.2 (3.8), BMI: 29.22 (2.3)

N = 26, Age: 28.1 (4.3), BMI: 28.3 (1.9)

–

Group 1: before conception till the end of pregnancy

Group 2: –

2ed trimester

Group 1: 3.2

Group 2: 23.08

Begum et al. (2009)¹

Rotterdam

Time: NM guideline: NM

N = 29, Age: 28.1 (2.9), BMI: 28.2 (2.3)

N = 30, Age: 26.1 (3.6), BMI: 27.9 (2.4)

–

Group 1: before conception till the end of pregnancy

Group 2: before conception

Group 1: 3.44

Group 2: 30

Ashrafi et al. (2014)²

Rotterdam

Time: 24–28 w, guideline: ADA

–

N = 234, Age: 29.6 (3.9), BMI: (26.1)

Group 3a: non-PCOS, infertile

N = 234, Age: 30.7 (4.7), BMI: 25.5 (4.2)

Group 3b: non-PCOS, fertile

N = 234, Age: 26.4 (5.5), BMI: 25.7 (3.8)

Group 2: before conception

Group 3: –

Group 4: –

Group 1: 44.4

Group 3a: 29.9

Group 3b: 7.3

Ashrafi et al. (2017)²

Rotterdam

Time: 24–28 w, guideline: ADA

–

Group 2a: HA + AO + PCO

N = 113, Age: 29.5 (3.8), BMI: 26.1 (3.1)

Group 2b: AO + HA

N = 5, Age: 28.6 (5.4), BMI: 27.7 (3.2)

Group 2c: HA + PCO

N = 74, Age: 29.90 (4.2), BMI: 25.94 (4.1)

Group 2d: AO + PCO

N = 16, Age: 28.3 (2.8), BMI: 25.9 (2.1)

–

Group 2a: no

Group 2b: no

Group 2c: no

Group 2d: no

Group 2a: 46

Group 2b: 100

Group 2c: 41.9

Group 2d: 43.8

Bjercke et al. (2002)³

NIH

TIME: NM, guideline: NM

–

Group 2 a: without IR

N = 29, Age: 31.5 (3.8), BMI: 25.2 (3.9)

Group 2 b: with IR

N = 23, Age: 31.1 (4.0), BMI: 27.7 (5.5)

N = 355, Age: 32.7 (3.4), BMI: 21.9 (2.7)

–

Group 2a: 7

Group 2b: 9

Group 3: 0.6

D’Anna et al. (2012)³

NM

Time: 24–28 w, guideline: NM

–

N = 37, Age: 30.6 (4.2),

BMI: 24.7 (3.9)

–

Group 2: before conception

Group 2: 54

De Fre`ne et al. (2014)³

Rotterdam

Time: ~ 24 w, guideline: ADA

–

Group 2 a: overweight

N = 93, Age: 29 (4.2), BMI: 30.8 (27.7–33.5)^a

Group 2 b: Normal weight

N = 107, Age: 28.4 (3.1), BMI: 20.9 (20–22.3)^a

–

Group 2 a: NO

Group 2 b: NO

Group 2 a: 8.2

Group 2 b: 0

De Leo et al. (2011)³

AES

Time: NM, guideline: NM

N = 98, Age: 32 (6), BMI: 28.3 (2.1)

–

N = 110, Age: 33 (5), BMI: 26.6 (1.2)

Group 1: before conception till 37 weeks’ gestation

Group 2:–

Group 1: 0

Group 3: 12.5

deWilde et al. (2015)³

Rotterdam

Time: 24–26 w, guideline: ADA

–

N = 72, Age: 29.6 [26.8–31.8]^a, BMI: 24.4 [21.6–28.9]^a

–

Group 2: before conception

Group 2: 31

deWilde et al. (2014)³

Rotterdam

Time: 24–26 w, guideline: NM

–

N = 189, Age: 29 [27–31]^a, BMI: 24 [21–28]^a

–

Group 2: before conception

Group 2: 22

Dmitrovic et al. (2011)²

NIH

Time: 6–10, 12–16, 24–28, 34–38 w, guideline: ADA

–

N = 17, Age: 29 (4), BMI: 32 (8)

N = 17, Age: 31 (5), BMI: 26 (7)

Group 2: –

Group 3: –

Group 2: 47

Group 3: 12

Elkholi et al. (2016)²

Rotterdam

Time: 24–28 w, guideline: ADA

–

Group 2a: metabolically obese

N: 62, Age: 22.3 (1.2), BMI: 21.4 (1.5)

Group 2b: metabolically healthy

N: 47, Age: 21.1 (1.6), BMI: 21.6 (1.4)

N: 35, Age: 20.4 (1.3), BMI: 21.3 (1.4)

Group 2a: before conception

Group 2b: before conception

Group 3: No

Group 2a: 9.8

Group 2b: 0

Group 3: 0

Fougner et al. (2008)¹

Rotterdam

Time: 19, 32, 36 w, guideline: WHO

N = 18, Age: 28.9 (26.5–31.4)^a, BMI: 32.1 (29.1–35.2)^a

N: 22, Age: 28.3 (26.6–30.0)^a, BMI: 29.3 (25.8–32.9)^a

–

Group 1: before conception till the end of pregnancy

Group 2: before conception

First trimester

Group 1: 11.1

Group 2: 27.2

2ed trimester

Group 1: 11.1

Group 2: 4.5

3rd trimester

Group 1: 22.2

Group 2: 9

Glueck et al. (2004)³

Rotterdam

Time: 26–28 w, guideline: ADA

N = 90, Age: 33 (5), BMI: 33.8 (7.8)

–

N = 252, Age: 29 (6), BMI: 25.6 (5.9)

Group 1: before conception till the end of pregnancy

Group 3: –

Group 1: 9.5

Group 3: 15.9

Glueck et al. (2004)³

Rotterdam

Time: 26–28 w, guideline: ADA

N = 39, Age: 30 (4), BMI: 34 (8.2)

–

–

Group 1: before conception till the end of pregnancy

Group 1: 7.6

Glueck et al. (2002)³

NIH

Time: 26–28 w, guideline: ADA

N = 33, Age: 34 (8), BMI: 33.9

–

–

Group 1: before conception till the end of pregnancy

Group 1: 33

Glueck et al. (2013)³

Rotterdam

Time: NM, guideline: NM

N = 76, Age: 32 (5), BMI: 33.3 (7.4)

–

N = 156, Age: 30 (6), BMI: 26.9 (6.6)

Group 1: before conception till the end of pregnancy

Group 3:–

Group 1: 10.5

Group 3: 14.7

Glueck et al. (2008)³

Rotterdam

Time: 26–28 w, guideline: ADA

N = 142, Age: 30 (5), BMI: 33.5 (7.9)

–

–

Group 1: before conception till the end of pregnancy

Group 1: 7

Glueck et al. (2002)³

Rotterdam

Time: 26–28 w, guideline: ADA

–

N = 68, Age: –, BMI: 33 (29–38.8)^a

–

Group 2: before conception

Group 2:

Haakova et al. (2003)³

Rotterdam

Time: second, third trimester, guideline: NM

–

N = 66, Age: 29.8 (4.9), BMI: 23.2 (3.8)

N = 66, Age: 29 (4.9), BMI: 23.2 (3.8)

Group 2: –

Group 3: –

Group 2: 4.92

Group 3: 12.12

Han et al. (2011)³

Rotterdam

Time: 24 w, guideline: ADA

–

Group 2a: Obese

N = 64, Age: 31.6 (3.1), BMI: 27.46 (2.4)

Group 2b: Non-obese

N = 272, Age: 31.2 (2.7), BMI: 20.45 (2.0)

Group 3a: Obese

N = 117, Age: 32.2 (3.2), BMI: 27.5 (2)

Group 3b: Non-obese

N = 886, Age: 32.5 (2.8), BMI: 20.5 (1.9)

Group 2a: no

Group 2b: no

Group 3a: no

Group 3b: no

Group 2a: 10.5

Group 2b: 1.1

Group 3a: 8.6

Group 3b: 1.8

Hassanzahraeiet al. (2007)³

NIH

Time: 24–28 w, guideline: NDDG

–

N = 47, Age: 27.8 (5.2), BMI: 25.1 (4.4)

N = 100, Age: 28 (4.9), BMI: 23.4 (3.3)

Group 2: –

Group 3: –

Group 2: –

Group 3: –

Joham et al. (2014)²

NM

Time: NM, guideline: NM

–

N = 478, Age: 30.5 (1.4), BMI: 28 (7.2)

N = 8134, Age: 30.6 (1.5), BMI: 25.1 (5.6)

Group 2: –

Group 3: –

Group 2: 11.2

Group 3: 3.8

Khattab et al. (2011)³

Rotterdam

Time: 5–12, 19, 32, 36 w, guideline: WHO

N = 31, Age: 30.2 (3.8), BMI: 29.22 (2.3)

N = 31, Age: 30.2 (3.8), BMI: 29.22 (2.3)

–

Group 1: before conception till the end of pregnancy

Group 2: before conception

Group 1: 4

Group 2: 20

Kollmann et al. (2015)³

1-NIH

2. Rotterdam (HA + PCO)

3. Rotterdam (OA + PCO)

Time: 24–28 w, guideline: IADPSG

–

Group 2a: NIH criteria

N = 85, Age: 29 (26–32)^a, BMI: 24.3 (21.4–29.2)^a

Group 2b: Rotterdam (HA + PCO)

N = 14, Age: 31 (26–33) ^a, BMI: 25.5 (22.1–31.2)^a

Group 2c: Rotterdam (OA + PCO)

N = 78, Age: 30 (27–33)^a, BMI: 24.2 (20.5–29.7)^a

N = 708,Age: 30 (25–34)^a, BMI: 22.5 (20.5–25.8)^a

Group 2a: –

Group 2b: –

Group 2c: –

Group 2a: 18.8

Group 2b: 14.3

Group 2c: 26.9

Group 3: 2.5

Lesser et al. (1997)³

NIH

Time: 20–28 w, guideline: NDDG

–

N = 24, Age: 29.8 (5.3), BMI: 28.4 (4.7)

N = 44, Age: 32 (4.6), BMI: 23.4 (2.79)

Group 2: no

Group 3: no

Group 2: 16.7

Group 3: 6.7

Mehrabian et al. (2013)³

Rotterdam

Time: 24–28 w, guideline: ADA

–

Group 2a: PCOS with GDM

N = 50, Age: 34 (47.5), BMI: 28.9 (4.5)

Group 2a: PCOS without GDM

N = 130, Age: 33.3 (6.6), BMI: 25.9 (4.5)

–

Group 2: no

Group 2 totally: 27.8

Mikola et al. (2001)³

NIH

Time: NM, guideline: NM

–

N = 99, Age: 30.4 (3.9), BMI: 25.6 (6.5)

N = 737, Age: 29.4 (4.8), BMI: 23 (4.6)

Group 2: no

Group 3: no

Group 2: 20

Group 3: 9

Mumm et al. (2015)³

Rotterdam

Time: 14–20, 28–30 w guideline: NM

–

N = 157, Age: 29 (26–32)^a, BMI: 25.9 (22.0–32.0)^a

N = 995, Age: 29 (26–33)^a, BMI: 23.2 (20.9–26.1)^a

Group 2: no

Group 3: no

Group 2: 6.4

Group 3: 13.8

Naver et al. (2014)³

Rotterdam

Time: NM, guidelines: national

–

N = 459, Age: 31.6, BMI: 22.9

N = 5409, Age: 30.7, BMI: 23.4

Group 2: no

Group 3: no

Group 2: 2.4

Group 3: 1.1

Nawaz et al. (2008)³

Rotterdam

Time: 24–28 w, guideline: NM

Group 1a:

N = 40, Age: 28 (3.6), BMI: 29.6 (5.1)

Group 1b:

N = 20, Age: 29 (3.1), BMI: 30 (2.6)

Group 1c:

N = 45, Age: 27 (4.2), BMI: 29.3 (3.3)

N = 32, Age: 30 (2.9), BMI: 31.2 (4.6)

–

Group 1a: before conception till 4–16 weeks of gestation

Group 1b: before conception till 32 weeks of gestation

Group 1c: before conception till the end of pregnancy

Group 2: no

Group 1a: 37.5

Group 1b: 50

Group 1c: 28.8

Group 2: 40.6

Ott et al. (2014)³

Rotterdam

Time: second trimester, guideline: NM

–

Group 2a: conceived with LOA + metformin

N = 40, Age: 27.8 (4.9), BMI: 26.9 (5.0)

Group 2b: conceived with CC + metformin

N = 40, Age: 27.5 (4.5), BMI: 28.0 (6.0)

Group 2c: conceived with metformin only

N = 40, Age: 27.2 (4.6), BMI: (27.2 ± 5.6)

–

Group 2a: before conception

Group 2b: before conception

Group 2c: before conception

Group 2a: 29.4

Group 2b: 31.3

Group 2c: 31.4

Palomba et al. (2010)³

Rotterdam

Time: NM, guideline: NM

–

N = 93, Age: 30 (20–33)^a, BMI: 24.2 (18.1–29.1)^a

N = 73, Age: 30 (19–34)^a, BMI: 24 (17.8–29.4)^a

Group 2: no

Group 3: no

Group 2: 16.1

Group 3: 5.8

Paradisi et al. (1998)³

NIH

Time: NM, guideline: NM

–

Grou2a: PCOS with GDM

N = 5, Age: 32.2 (6.3), BMI: 28.3 (0.7)

Group 2b: PCOS without GDM

N = 8, Age: 28 (2.9), BMI: 28.3 (3.2)

–

Group 2: no

Group 2: 38.4

Radon et al. (1999)³

ICD-9th revision

Time: 24–28 w, guideline: NM

–

N = 22, Age: 32.4 (4.1), BMI: 28.9 (8)

N = 66, Age: 31.1 (3.9), BMI: 28 (7.2)

Group 2: no

Group 3: no

Group 2: 40.9

Group 3: 3

Reyes-Muñoz et al. (2012)³

Rotterdam

Time: 14–24 or 24–28 w, guideline: ADA

–

N = 52, Age: 29.1 (3.9), BMI: 27.5 (3.1)

N = 26, Age: 29 (3.8), BMI: 27.5 (3.3)

Group 2: before conception

Group 3: –

Group 2: yes

Group 3: no

Sterling et al. (2016)³

Rotterdam criteria

Time: NM, guideline: NM

–

N = 71, Age: 33 (30–35)^a, BMI: 22.7 (20.4–28.3)^a

N = 323, Age: 35 (32–37)^a, BMI: 22.6 (20.8–26.0)^a

Group 2: no

Group 3: no

Group 2: 15.5

Group 3: 5

Turhan et al. (2003)³

NIH

Time: 24–28 w, guideline: ADA

–

N = 38, Age: 27.6 (3.7), BMI: 31.5 (4.5)

N = 136, Age: 26.6 (4.7), BMI: 23.6 (4.3)

Group 2: no

Group 3: no

Group 2: 2.6

Group 3: 8.1

Vollenhoven et al. (2000)³

NM

Time: 24–28 w, guideline: WHO

–

N = 60, Age: –, BMI: 27.1 (5.2)

N = 60, Age: –, BMI: 26.5 (4.9)

Group 2: no

Group 3: no

Group 2: 22

Group 3: 17

Vanky et al. (2004)¹

Rotterdam

Time: 19, 32, 36 w, guideline: WHO

N = 18, Age: 28.9 (4.8), BMI: 32.1 (6.1)

N = 22, Age: 28.3 (3.7), BMI: 29.3 (8)

–

Group 1: before conception till the end of pregnancy

Group 2: before conception

First trimester

Group 1: 16.6

Group 2: 27.2

2ed trimester

Group 1: 11.1

Group 2: 4.5

3rd trimester

Group 1: 22.2

Group 2: 9

Vanky et al. (2010)¹

Rotterdam

Time: NM, guideline: NM

N = 135, Age: 29.6 (4.4),

BMI: 29.5 (7)

N = 138, Age: 29.2 (4.4), BMI: 28.5 (7.2)

–

Group 1: before conception till the end of pregnancy

Group 2: before conception

Group 1: 16.2

Group 2: 15.2

Vanky et al. (2011)²

1. NIH

2. Rotterdam

Time: 14, 28 w, guideline: WHO

–

Group 2a: PCOS based on NIH criteria

N = 164, Age: 29.1 (4.4), BMI: 29.5 (6.62)

Group 2a: PCOS based on Rotterdam criteria

N = 93, Age: 29.6 (4.4), BMI: 27.4 (6.4)

–

Group 2a: no

group 2b: no

First trimester

Group 2a: 9

group 2b: 10

2ed trimester

Group 2a: 11.1

Group 2b: 4.5

3rd trimester

Group 1: 10

Group 2: 7

Veltman-Verhulst et al. (2010)³

Rotterdam

Time: 24–26 w, guideline: ADA

–

Group 2a: PCOS with GDM

N = 21, Age: 26.6 (3.5), BMI: 28.2 (5.8)

Group 2a: PCOS without GDM

N = 29, Age: 25.6 (3.0), BMI: 24.7 (5.7)

–

Group 2: –

Group 2 totally: 42

Wan et al. (2015)³

Rotterdam

Time: NM, guideline: WHO

–

N = 25, Age: 31.4 (2), BMI: 22.8 (3.6)

N = 174, Age: 32.7 (3.1), BMI: 21.5 (2.6)

Group 2: no

Group 3: no

Group 2: 29.2

Group 3: 29.8

Wang et al. (2013) (120)³

Rotterdam

Time: 24–28 w, guideline: ADA

–

N = 144, Age: 30.8 (3.9), BMI: 23 (2.6)

N = 594, Age: 29.1 (3.9), BMI: 20 (2.4)

Group 2: no

Group 3: no

Group 2: 54.9

Group 3: 14.3

Weerakiet et al. (2004)³

NM

Time: 24–28 w, guideline: ADA

–

N = 47, Age: 31.6 (4), BMI: 24 (3)

N = 264, Age: 31.3 (3.8), BMI: 22.1 (3.6)

Group 2: no

Group 3: no

Group 2: 22.2

Group 3: 18

Xia et al. (2017)³

Rotterdam

Time: 24–28 w, guideline: NM

–

Group 2a: PCOS with GDM

N = 31, Age: –, BMI: 24.0 (6.4)

Group 2a: PCOS without GDM

N = 63, Age: –, BMI: 23.2 (3.0)

–

Group 2 totally: no

Group 2 totally: 32.9

Zhang et al. (2016)²

Rotterdam

Time: 24–28 w, guideline: ADA

–

Group 2a: PCOS with GDM

N = 45, Age: 28.87 (3.20),

BMI: 24.30 (3.23)

Group 2a: PCOS without GDM

N = 223, Age: 28.06 (3.2), BMI: 23.2 (3.1)

–

–

Group 2 totally: 16.7