Table 1 Characteristics of included studies

Chokwiriyachit A et al., [19] (Thailand)

Hospital based, case–control, 2009 to 2010

Age range 14–45, 50 GDM 50 controls

1 site with (PD) ≥5 mm and (CAL) ≥2 mm at the same site.

2 step O’Sullivan’s criteria OGTT screening was performed at 24 to 28, and ≥2 abnormal values was diagnostic of GDM

OR = 7.92 (1.66 to 37.7) FH of DM, pre-pregnancy BMI, and weight gain during pregnancy.

Results suggest association between periodontitis and GDM

High

Ruiz DR et al., [47] (Brazil)

Hospital based, case–control, 2011

161 pregnant women, 80 GDM mean age 33 years., 50 controls mean age 27 years.

Probing on six sites per tooth and periodontal parameters were evaluated, GM, PD, CAL, PI, BI, BOP and MI

2 step Carpenter and Coustan criteria. 2 step OGTT screening was performed at 24 to 28, and ≥2 abnormal values was diagnostic of GDM

(GA, age, FPG, pre-BMI, and HbA_1c)

Periodontitis was significantly higher in Brazilian diabetic pregnancies (GDM and T1DM) compared to non-diabetic pregnant women

Medium

Xiong, X et al., [26] (USA)

Hospital based, case–control 2007 and 2008, 159 pregnant women, 53 GDM mean age 29.9, 106 controls mean age 27.1

Any site with a PD ≥ 4 mm or a CAL ≥ 4 mm.

2 step Carpenter and Coustan criteria. 2 step OGTT screening was performed at 24 to 28, and ≥2 abnormal values was diagnostic of GDM

2.6 (1.1–6.1)

Age, parity, race, marital status, education, income, smoking, alcohol, antibiotics use, family history of DM, income, dental insurance BMI

This study supports the hypothesis of an association between periodontal disease and GD

High

Dasanayake AP et al., [24] (USA)

Hospital based, nested case–control, 262 pregnant women, 22 GDM mean age 28.7, 240 controls mean age 26.6

≥1 pocket with PD > 3 mm

2 step Carpenter and Coustan criteria. 2 step OGTT screening was performed at 24 to 28, and ≥2 abnormal values was diagnostic of GDM

OR = 1.68 (0.52-5.43)

(Bivariate analysis)

Prior GDM, pre-pregnancy BMI

Periodontal disease did not differ b/n those with GDM and controls

High

Lima E et al., [27] (Brazil)

Hospital based, case–control, 2010 to 2011 360 pregnant women, aged 18–44 mean age 27.2, 90 GDM mean age 32.9, 270 control mean age 25.3

BOP, PD, CAL in 4 sites of all present teeth. ≥4 teeth, with >1 site having PD ≥4 mm was diagnostic

ADA standard for screening and diagnosis of GDM

OR = 0.74 (0.40 to 1.38)

Maternal age, marital stability, parity, smoking, alcohol consumption, chronic HPN and BMI

High prevalence of periodontitis was found among cases and controls with no association between periodontitis and GDM

High

Mishra P et al. [45] India

Hospital based, 2009 to 2011 case–control, 90 pregnant women, 30 GDM with mean age 28, 60 control mean age 24

Any site with PD ≥ 4 mm and clinical AL ≥ 3 mm

1-h, 50-g oral glucose challenge test (GCT). If the glucose level was >135 mg/dl (GCT positive)

Generalized:

OR = 0.49

(0.07 to 3.52)

Localized:

OR = 0.54

(0.08 to 3.79)

The results of this study showed that periodontal disease is not significantly associated with GDM

Low

Bagis et al. [42] (Turkey)

Hospital based, 2004 to 2005 case–control, 165 pregnant women, 85 GDM: 80 control, with mean age 28, 60 control mean age 25.85

Assessed using PI; GI; PPD;

BOP

2 step Carpenter and Coustan criteria. 2 step OGTT screening was performed at 24 to 28, and ≥2 abnormal values was diagnostic of GDM

NR

Compared to healthy pregnant women, the values

GI and BOP were significantly higher for women with GDM

Medium

Bullon P, et al. (2013) (Spain)

Hospital based, cross-sectional, 2013, 188 pregnant women ages 16–44 years., 26GDM, 162 controls

≥2 interproximal sites with CAL ≥6 mm (not on the same tooth) and ≥1 interproximal site with PD ≥5 mm

2 step O’Sullivan’s criteria OGTT screening was performed at 24 to 28, and ≥2 abnormal values was diagnostic of GDM

Periodontitis

Periodontitis in GDM vs. No-GDM (15.5 % vs. 5.6 %; P = 0.086)

Plague positive OR = 1.012 (1.0 to 1.02). Periodontal disease may be associated with GDM

Not assessed

Habib FA et al. [44] (Saudi)

Hospital based, 250 pregnant women, mean age 32, 100 GDM, 100 pregnant non-GDM and 50 non pregnant women

The Community Periodontal Index of Treatment Needs (CPITN)

2 step Carpenter and Coustan criteria. 2 step OGTT screening was performed at 24 to 28, and ≥2 abnormal values was diagnostic of GDM

NR

GDM; showed significant positive correlation between CPITN scoring

Not assessed

Novak, KF et al. [46] (USA)

Cross-sectional, National Health and Nutrition Examination Survey (NHANES) III sample 4070 pregnant women, age 20 to 59, 88 GDM, 3982 controls

≥1 teeth with ≥1 site with probing pocket depth ≥ 4 mm, clinical attachment loss ≥ 2 mm and bleeding on probing

GDM: Self reported

OR = 2.7 (0.7 to 10.5)

Age, presence of sub-gingival calculus, history of smoking, and income

GDM was associated with severe periodontal disease than those without GDM, the association was not statistically significant

Not assessed