Table 1.
Characteristics of the covariates and main dependent variables.
| Variates | Definitions and Categories | Description |
|---|---|---|
| Pre-pregnancy BMI | (the quotient of pre-pregnancy weight (kg) and height (meters) squared) BMI was assessed as a continuous variable (as a covariate); BMI was assessed in the 5 following categories (as subgroups): (1) underweight (<18.5); (2) normal weight (18.5–24.9); (3) overweight (25.0–29.9); (4) obesity (≥30); and (5) BMI ≥ 25 kg/m2. |
Self-reported |
| GWG | (the difference between the weight before childbirth and the weight before pregnancy) GWG was assessed in the three following categories, regardless of BMI category (according to the Institute of Medicine recommendations from 2009): (1) GWG above the range; (2) GWG in the range; (3) GWG below the range. GWG out of the range was a covariate. |
From medical reports |
| Maternal age | (defined as completed maternal age at conception, in years) Maternal age was assessed as a continuous variable (as a covariate) |
From medical reports |
| Primiparity | Parity was assessed in the two following categories: (1) primiparity (zero prior delivery); (2) multiparity (i.e., ≥1 prior deliveries). Primiparity was a covariate. | From medical reports |
| Smoking | Smoking was assessed in the three following categories: (1) mothers who had never smoked; (2) smokers (smoked before pregnancy); (3) smokers in the first trimester. Smokers in the first trimester was a covariate. The three smoking categories was assessed as subgroups. |
Self-reported |
| Prior PIH | Mothers with pregnancy-induced hypertension (gestational hypertension or preeclampsia, GH/PE) in previous pregnancies. Prior PIH was assessed in the two following categories: (1) prior PIH; (2) no prior PIH. Prior PIH was a covariate. |
From medical reports |
| Infertility treatment | (Different methods of infertility treatment, covering in vitro fertilization and other methods of assisting reproduction) Infertility treatment was assessed in the two following categories: (1) infertility treatment; (2) no infertility treatment. Infertility treatment was a covariate. |
From medical reports |
| Education | Education level was assessed in the following categories: (1) ≥12 years of education (secondary education and tertiary education); (2) <12 years of education (primary and vocational education) | From medical reports |
| Financial status | Financial status was assessed on the 5-point Likert scale. The basis of assessment was the question ‘Is your household’s financial status sufficient for your needs?’ and the 5 following answers: ‘1—definitely No’; ‘2—rather No’; ‘3—hard to say’; ‘4—rather Yes’; ‘5—definitely Yes’. Financial status was assessed in the following categories: (1) Lower financial status (the answers/levels 1–3); and (2) Higher financial status (the answers/levels 4–5). |
Self-reported |
BMI—Body mass index; GWG—gestational weight gain; PIH—Pregnancy-induced hypertension.