Table 4.

Distributions of the interpregnancy interval by significantly differing maternal characteristics

	<20		20−24		25−29		30−34		35−39		>40
Age (years)	n	%	n	%	N	%	n	%	n	%	n	%	p
<6 months	26	24.76	33	31.43	27	25.71	10	9.52	8	7.62	1	0.95	<0.0001
6−12 months	49	27.53	65	36.52	40	22.47	19	10.67	5	2.81	0	0
>12 months	322	7.02	1,363	29.71	1,555	33.89	934	20.36	343	7.48	71	1.55
	Yes		No		N/A
Cohabiting	n	%	n	%	N	%	p
<6 months	84	80.77	13	12.50	7	6.73	0.0116
6−12 months	141	79.21	32	17.98	5	2.81
>12 months	3,615	78.98	551	12.04	411	8.98
	Underweight		Normalweight		Overweight
Weight	n	%	n	%	N	%	p
<6 months	7	6.67	76	72.38	22	20.95	0.0601
6−12 months	13	7.30	114	64.04	51	28.65
>12 months	229	4.99	2,863	62.40	1,496	32.61
	No smoking		Stopped in first trim		Continued after first trim		N/A
Smoking	n	%	n	%	N	%	n	%	p
<6 months	64	60.95	8	7.62	32	30.48	1	0.95	0.0098
6−12 months	99	55.62	16	8.99	61	34.27	2	1.12
>12 months	2,865	62.45	596	12.99	1,063	23.17	64	1.39