N | Outcomes* | Metformin cohort versus naïve cohort OR (95% CI) | ||||
Exposed to metformin | Naïve cohort† | Exposed to metformin | Naïve cohort† | |||
Outcome | Unadjusted | IPTW-weighted‡ | ||||
SGA | ||||||
Main analyses with metformin cohort§ | 3964 | 82 675 | 92 (2.3) | 1659 (2.0) | 1.16 (0.94 to 1.43) | 0.97 (0.73 to 1.27) |
Additional analyses with metformin-GDM subcohort¶ | 2361 | 82 675 | 51 (2.2) | 1659 (2.0) | 1.08 (0.81 to 1.43) | 1.01 (0.75 to 1.37) |
LGA | ||||||
Main analyses with metformin cohort§ | 3964 | 82 675 | 159 (4.0) | 3415 (4.1) | 0.97 (0.82 to 1.14) | 0.91 (0.75 to 1.11) |
Additional analyses with metformin-GDM subcohort¶ | 2361 | 82 675 | 111 (4.7) | 3415 (4.1) | 1.14 (0.94 to 1.39) | 0.72 (0.56 to 0.92) |
*The numbers of outcomes represent counts in the main cohort before trimming of children outside the overlapping range of propensity scores.
†Naïve cohort refers to children of mothers with GDM exposed to non-pharmacological antidiabetic treatment. The naïve cohort has a 100% GDM rate, by definition, thus the number of outcomes and cohort size is the same for both the main analyses and additional analyses.
‡Covariates used in IPTW: mother’s age at delivery, calendar year of the childbirth, child’s region of residency at birth, maternal comorbidities before pregnancy (pregestational T2DM and PCOS), maternal comorbidities during pregnancy (any toxemia in pregnancy, essential hypertension, gestational hypertension, pre-eclampsia), parity, educational level, maternal smoking during pregnancy, maternal prepregnancy, BMI, gestational week of GDM diagnosis).
§Main analyses: cases with unknown outcome (3 in metformin cohort and 70 in naïve cohort) are not included in the denominator (%).
¶Additional analyses: cases with unknown outcome (0 in metformin-GDM subcohort and 70 in naïve cohort) are not included in the denominator (%).
GDM, gestational diabetes mellitus; IPTW, inverse probability of treatment weighting; LGA, large for gestational age; N, number; PCOS, polycystic ovary syndrome; SGA, small for gestational age; T2DM, type 2 diabetes mellitus.