Gestational weight gain outside the Institute of Medicine recommendations and adverse pregnancy outcomes: analysis using individual participant data from randomised trials

Table 1 Characteristics of women in the control arms of randomised trials included in the analyses

Characteristics	Number of studies (women)	Mean (SD) or Frequency (%)
Age (years)	32 (4415)	30.1 (5.1)
Height (cm)	31 (4422)	165.0 (7.0)
Weight^a (kg)	33 (4429)	77.13 (18.4)
Body Mass Index (kg/m²)	31 (4429)	28.32 (6.37)
Body Mass Index categories	31 (4429)
Healthy BMI (BMI 18.5–24.99 kg/m²)^b		1622 (36.6)
Overweight (BMI 25–29.99 kg/m²)		1245 (28.1)
Obese (BMI ≥ 30 kg/m²)		1562 (35.3)
Ethnic origin	24 (3536)
Caucasian		3232 (91.3)
Non-Caucasian		304 (8.7)
Education level^c	27 (3332)
Basic		453 (13.6)
Intermediate		1019 (30.6)
Higher		1860 (55.8)
Parity	30 (4317)
0		2113 (49.0)
1+		2204 (51.0)
Current smoker	27 (3964)	693 (16.5)
Inactive before pregnancy^d	25 (2760)	1377 (50.1)
Family history of diabetes	10 (1784)	455 (26.2)
Hypertension at baseline	20 (2154)	53 (2.5)
Any hypertensive event in pregnancy^e	24 (3502)	318 (9.1)
Any case of diabetes-related events^f	31 (4422)	448 (10.1)
Gestational age at delivery (weeks)	31 (4419)	39.6 (1.6)

^aEarly or pre pregnancy weight;
^bequivalent of Body Mass Index (BMI) termed as normal in the World Health Organization classification [20]
^c’low’ (secondary education completed before A-levels), ‘medium’ (secondary education to A-level equivalent) or ‘high’ (any further/higher education) for details see Table 48 in Rogozinska et al. 2017 [33]
^dDefined as no exercise or sedentary lifestyle prior to pregnancy for details see Table 49 in Rogozinska et al. 2017 [33]
^ePregnancy Induced Hypertension, high blood pressure, pre-eclampsia;
^fGestational Diabetes Mellitus or pre-pregnancy Diabetes Mellitus;

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