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Table 1 Operational definitions of variables

From: Physical inactivity in early pregnancy and the determinants in an urban city setting of Kuala Lumpur, Malaysia

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
  1. a METs metabolic equivalents
  2. b B40 - bottom 40% earners in the population
  3. c M40 - middle 40% earners in the population
  4. d T20 - top 20% earners in the population
  5. e BMI body mass index