Table 2.

Socio-demographic characteristics stratified by the pre-pregnancy BMI (pBMI) (n 1456)

Variable	pBMI
	UW (n 140)		NW (n 891)		OW (n 230)		OB (n 195)			P value†	P value‡	P value§
	n	%	n	%	n	%	n	%	P value*	UW v. OB	NW v. OB	OW v. OB
Region									<0·001
Northern	55	39·3	316	35·5	70	30·4	40	20·5	<0·001	<0·001	<0·001	0·033
Central	31	22·1	207	23·2	55	23·9	49	25·1	0·921	0·492	0·519	0·725
Southern	30	21·4	168	18·9	55	24·3	43	22·1	0·268	0·919	0·326	0·547
Eastern	24	17·1	200	22·4	49	21·3	63	32·3	0·005	0·003	0·008	0·018
Educational level									<0·001
Less than undergraduate	23	16·5	112	12·7	33	14·4	54	27·8	<0·001	0·018	<0·001	0·001
Undergraduate	93	67·0	619	69·9	165	72·1	122	62·9	0·169	0·518	0·076	0·058
Postgraduate	23	16·5	755	17·4	31	13·5	18	9·3	0·031	0·036	0·003	0·141
Household monthly income (US$)									0·006
<1000	26	18·6	117	13·3	28	12·6	33	17·4	0·188	0·68	0·2	0·215
1000–<2000	49	35·0	376	42·8	98	43·9	94	49·5	0·072	0·006	0·067	0·215
2000–<3333	42	30·0	265	30·2	70	31·4	53	27·9	0·892	0·624	0·466	0·39
≥3333	23	16·4	120	13·7	27	12·1	10	5·3	0·007	0·001	0·002	0·021

UW, underweight; NW, normal weight; OW, overweight; OB, obese.

Continuous data are presented as the mean ± sd; categorical data are presented as the number (percentage of the same group).

UW, pBMI of <18·5 kg/m²; NW, pBMI of 18·5–23·9 kg/m²; OW, pBMI of 24–26·9 kg/m²; OB, pBMI OF ≥ 27 kg/m².

^* P value was analysed by chi-squared for categorical variables (P < 0·05).

^† P value (UW compared to OB).

^‡ P value (NW compared to OB).

^§ P value (OW compared to OB).

In 2019, the average exchange rate was US$1.00≈New Taiwan (NT)$30.