Table 1

Study population characteristics

CharacteristicsCases of GDM
n=20 905
Controls
n=209 050
P value
Pregnancy-related variable
Gestational age at index date*, mean (SD)29.4 (2.3)29.4 (2.3)1.00
AD exposure from 1DG to index date1152 (5.5)8589 (4.1)<0.0001
AD use during 6 months before gestation1448 (6.9)11 403 (5.4)<0.0001
Sociodemographic characteristics measured on 1DG
Age (years)
 <18126 (0.6)2916 (1.4)
 18–3415 123 (72.3)173 958 (83.2)<0.0001
 >345656 (27.1)32 176 (15.4)
Urban dwellers17 678 (84.6)172 597 (82.6)<0.0001
Social assistance recipients5704 (27.3)48 615 (23.3)<0.0001
Maternal comorbidities during 6  months before 1DG
Depression/anxiety§1419 (6.8)12 995 (6.2)0.001
Hypertension487 (2.3)2665 (1.3)<0.0001
Asthma†1714 (8.2)14 637 (7.0)<0.0001
Cardiovascular diseases§402 (1.9)3468 (1.7)0.004
Thyroid disorders†930 (4.5)6354 (3.0)<0.0001
Polycystic ovarian syndrome§18 (0.2)76 (0.1)0.0007
Healthcare services utilisation and medication use in the 6  months before 1DG
No of physician visits
 0–110 770 (51.5)112 674 (53.9)<0.0001
 ≥210 135 (48.5)96 376 (46.1)
Hospital admission/emergency department visit4278 (20.5)42 487 (20.3)0.63
Medications other than ADs‡
 09250 (44.2)95 412 (45.6)<0.0001
 1–24800 (23.0)46 869 (22.4)
 ≥36855 (32.8)66 769 (32.0)
At least one visit to psychiatrists652 (3.1)5523 (2.6)<0.0001
Healthcare service utilisation from 1DG until index date
Pregnancy follow-up by obstetricians/gynaecologists9756 (46.7)77 962 (37.3)<0.0001
  • *Index date=date of gestational diabetes identification for cases and corresponding date for matched controls.

  • †Based on ICD-9 or ICD-10 codes or prescriptions filled for hypertension, asthma and thyroid disorders.

  • ‡Included prescriptions filled for conditions other than depression/anxiety, hypertension, asthma and thyroids disorders.

  • §Based on ICD-9 or ICD-10 codes for depression/anxiety, cardiovascular diseases and polycystic ovarian syndrome.

  • AD, antidepressant; 1DG, first day of gestation; GDM, gestational diabetes mellitus.