Table 1 Operational definitions of variables
No | Word/Phrase | Operational Definition | Measurement Scale |
|---|---|---|---|
1 | Physical inactivity (Dependent variable) | Less than 7.5 METsa*hour/week or 150 min of moderate to vigorous activities in a week [1] | Yes/No |
2 | Age | Age at first antenatal booking based on identity card | Number in years |
3 | Marital status | Marital status verified by a legal marriage certificate | Married Unmarried |
4 | Primigravida | Pregnant for the first time | Yes/No |
5 | Ethnicity | Ethnicity as written in identity card | Malay Chinese Indian Others |
6 | Education level | Refers to the highest level of formal education | No formal education Primary school Secondary school Tertiary education |
7 | Household income | Combined household income according to the Department of Statistics Malaysia [38] categorized into low income (B40b), middle income (M40c) and high income (T20d) | B40b < RM4850 M40c RM4850-RM10959 T20d ≥ RM10960 |
8 | Caloric intake per day | Total energy intake in one day, measured by 24-h dietary recall (a proxy to hyperemesis gravidarum) | Numerical in Kilocalorie per day (kcal/day) |
9 | BMIe at booking | Body mass index at booking at first trimester | Numerical in kg/m2 |
10 | Occupation | Occupation reported by subject at booking | Public Private Self-employed Housewife/Unemployed |
11 | Husband’s occupation | Husband’s occupation reported by subject at booking | Public Private Self-employed Unemployed |
12 | Medical problem in previous pregnancy | Any medical problem or complications encountered during previous completed pregnancy (gestational diabetes, hypertensive disorders, anemia in pregnancy etc.) | Yes/No |
13 | History of miscarriage | Any experience of spontaneous pregnancy loss before completed 22 weeks of gestation | Yes/No |
14 | Grand multigravida | Pregnant for the sixth time or more | Yes/No |