Serum ferritin concentration in gestational diabetes mellitus and risk of subsequent development of early postpartum diabetes mellitus

Figures & data

Table 1 Baseline clinical characteristics, biochemical indices, GDM risk factors and pregnancy complications of pregnant women with GDM and their control group (n = 128)

Variables (mean ± SD)	GDM subjects (n = 64)	Control subjects (n = 64)	P value
Age (year)	30 ± 4.7	30 ± 4.9	0.8
Weight (kg)	75 ± 8	67.6 ± 9.9	0.00
BMI (kg/m^2)	30.2 ± 3.2	27 ± 3.9	0.06
Systolic BP (mmHg)	111.7 ± 16	106.7 ± 11.9	0.06
Diastolic BP (mmHg)	72.8 ± 11.4	67.7 ± 9.1	0.01
Gravidity	2.8 ± 1	2.5 ± 0.9	0.9
Parity	1.2 ± 0.6	1.3 ± 0.8	0.4
Hb (g/dL)*	128 ± 8	125 ± 5.8	0.9
Ferritin (pmol/L)*	112.3 ± 28.4	65 ± 16.9	0.001
CRP (mg/L)*	9.2 ± 1.7	7.3 ± 0.6	0.09
FPG (mmol/L)*	5.8 ± 0.18	4 ± 0.27	0.01
Insulin (pmol/L)*	201 ± 111	347 ± 166	0.01
GDM risk factors (freq)
History of abortion	9 (14.1%)	4 (6.2%)	0.1
History of stillbirth	5 (7.8%)	1 (1.5%)	0.1
History of prior GDM	5 (7.8%)	0 (0%)	0.03
Family history of DM	30 (47%)	3 (4.6%)	0.001
Pregnancy morbidities (freq)
Pre-eclampsia and eclampsia	4 (6.7%)	0	0.1
Hypertension	10 (16.7%)	0	0.001
PPROM	2 (3.1%)	2 (3.1%)	0.6
Premature labor	5 (7.8%)	1 (1.5%)	0.1
Dystocia	3 (4.6%)	0	0.2
Abortion	1 (1.6)	0	0.3
LGA	13 (20.3)	0	0.00
LBW	0	0	1
Cesarean section	45 (70.3%)	15 (23.4%)	0.00

* Note: All the measurements were performed at 24–28 weeks of pregnancy.

Abbreviations: BMI, body mass index; BP, blood pressure; Hb, hemoglobin; FPG, fasting plasma glucose; GDM, gestational diabetes mellitus; DM, diabetes mellitus; PPROM, preterm premature rupture of membrane; LGA, large for gestational age; CR P, C-reactive protein; freq, frequency; LBW, low birth weight.

Table 2 Logistic regression analyses of ferritin and other confounding variables to predict GDM in the pregnant women

Dependent variable	Independent variables	OR	CI (95%)
Model 1
GDM	Ferritin	4.4	1.2–16.8
	Family history of DM	11.5	3–43.3
	BMI	2.6	1.2–5.4
	Age	0.98	0.9–1.07
Model 2
GDM	Ferritin	5.8	1–38
	Family history of DM	11.3	2.7–46
	BMI	2.9	1.2–7.1
	Age	0.98	0.89–1.08
	Systolic BP	0.69	0.3–1.2
	Diastolic BP	2.3	1.1–4.9
Model 3
GDM	Ferritin	5.1	1–34
	Family history of DM	11.2	2.6–45
	BMI	2.8	1.2–4.9
	Age	0.97	0.89–1.05
	Systolic BP	0.7	0.35–1.3
	Diastolic BP	2.4	1.1–5.1
	CRP	0.91	0.7–1.09

Abbreviations: GDM, gestational diabetes mellitus; DM, diabetes mellitus; BMI, body mass index; BP, blood pressure; CR P, C-reactive protein; OR, odds ratio; CI, confidence interval.

Table 3 Comparison of basal clinical characteristics, biochemical indices, past history, and pregnancy complications between two groups of women with GDM based on their postpartum OGTT results (n = 64)

Variables (mean ± SD)	Impaired glucose tolerance or DM (n = 23)	Normal glucose tolerance (n = 41)	P
Age (years)	30.3 ± 1.1	30.4 ± 0.7	0.9
BMI (kg/m^2)	31.3 ± 0.5	29.6 ± 0.5	0.06
Systolic BP (mmHg)	118 ± 40	107.7 ± 21	0.01
Diastolic BP (mmHg)	77 ± 25	70 ± 17	0.03
Hb (g/dL)	129 ± 2.3	128 ± 1.8	0.8
Ferritin (pmol/L)	107.8 ± 22	115.9 ± 24.7	0.8
CRP (mg/L)	9.5 ± 1.5	8.9 ± 1.9	0.09
FPG (mmol/L)	6.1 ± 0.2	5 ± 0.17	0.00
Insulin (pmol/L)	234 ± 122	182 ± 99	0.06
1-hour BS in GTT (mmol/L)	10.8 ± 0.76	9.6 ± 0.3	0.08
2-hour BS in GTT (mmol/L)	10.8 ± 0.85	9.8 ± 0.58	0.3
3-hour BS in GTT (mmol/L)	9.4 ± 1.2	7.8 ± 0.3	0.3
HbA1c (%)	5.16 ± 0.19	5.1 ± 0.16	0.8
GDM risk factors (freq)
History of abortion	4 (17.3)	5 (12)	0.9
History of stillbirth	2 (8.7)	3 (7.3)	0.6
History of prior GDM	4 (17.3)	1 (2.4)	0.06
Family history of DM	16 (69.5)	14 (34)	0.08
Pregnancy morbidity (freq)
Pre-eclampsia and eclampsia	4 (17.3)	0	0.06
Hypertension	4 (17.3)	2 (4.8)	0.1
PPROM	1 (4.3)	1 (2.4)	0.6
Premature labor	3 (13)	2 (4.8)	0.2
Dystocia	3 (13)	0	0.052
LGA	8 (34.7)	6 (14.6)	0.04
Cesarean section	18 (78.3)	27 (65.9)	0.2

Abbreviations: BMI, body mass index; BP, blood pressure; Hb, hemoglobin; FPG, fasting plasma glucose; CR P, C-reactive protein; 1-hour BS, blood sugar one hour post-OGTT in mid-pregnancy; 2-hour BS, blood sugar two hours post-OGTT; 3-hour BS, blood sugar three hours post-OGTT; OGTT, oral glucose tolerance test; GDM, gestational diabetes mellitus; DM, diabetes mellitus; PPROM, preterm premature rupture of membrane; LGA, large for gestational age.