Table 2. Crude and AOR for the association between pre-pregnancy BMI and adverse outcomes.

Outcomes	BMI status	Case	Control	OR (95% CI)	P	AOR* (95% CI)	P
PTB	Underweight	75 (23.29)	783 (23.29)	1.04 (0.79–1.37)	0.787	1.01 (0.76–1.34)	0.943
	Normal weight	197 (61.18)	2137 (63.56)	1.00 (reference)		1.00 (reference)
	Overweight	40 (12.42)	355 (10.56)	1.22 (0.86–1.75)	0.272	1.25 (0.87–1.80)	0.224
	Obesity	10 (3.11)	87 (2.59)	1.25 (0.64–2.44)	0.519	1.27 (0.65–2.51)	0.486
LBW	Underweight	94 (29.65)	764 (22.69)	1.48 (1.14–1.93)	0.003	1.44 (1.11–1.89)	0.007
	Normal weight	179 (56.47)	2155 (64.00)	1.00 (reference)		1.00 (reference)
	Overweight	34 (10.73)	361 (10.73)	1.13 (0.77–1.66)	0.521	1.17 (0.80–1.73)	0.423
	Obesity	10 (3.15)	87 (2.58)	1.38 (0.71–2.71)	0.343	1.41 (0.72–2.78)	0.322
Gestational hypertension	Underweight	13 (9.92)	845 (23.78)	0.43 (0.24–0.78)	0.006	0.45 (0.25–0.82)	0.009
	Normal weight	80 (61.07)	2254 (63.44)	1.00 (reference)		1.00 (reference)
	Overweight	23 (17.56)	372 (10.47)	1.74 (1.08–2.81)	0.022	1.71 (1.06–2.77)	0.03
	Obesity	15 (11.45)	82 (2.31)	5.15 (2.85–9.33)	<0.001	5.54 (3.02–10.17)	<0.001
Cesarean delivery	Underweight	194 (17.60)	664 (25.72)	0.70 (0.59–0.84)	<0.001	0.74 (0.62–0.90)	0.002
	Normal weight	686 (62.25)	1684 (63.83)	1.00 (reference)		1.00 (reference)
	Overweight	180 (16.33)	215 (8.33)	2.01 (1.62–2.50)	<0.001	1.91 (1.53–2.38)	<0.001
	Obesity	42 (3.81)	55 (2.13)	1.84 (1.22–2.77)	0.004	1.85 (1.21–2.82)	0.004

Notes.

Abbreviations

OR

odds ratio

CI

confidence interval

AOR

adjusted odds ratio

PTB

preterm birth

LBW

low birth weight

^*Adjusted OR and 95% CI were calculated by the logistic regression model after adjusting for age, health insurance, occupation and education.