Table 2. Number^a of spontaneous abortions and gestational weeks at risk by maternal age and body mass index.

Age (Years)		Body mass index (kg/m2)
		<20	20–24	25–30	≥30	Total
≤20	SAB	4	7	4	4	19
	Gestational weeks	523	1101	476	339	2439
	Rate/1000 GW	7.6	6.4	8.4	11.8	7.8
21–24	SAB	18	44	16	16	94
	Gestational weeks	2634	7248	3505	1914	15 301
	Rate/1000 GW	6.8	6.1	4.6	8.4	6.1
25–28	SAB	39	123	41	42	245
	Gestational weeks	5584	19 678	7055	3916	36 233
	Rate/1000 GW	7.0	6.3	5.8	10.7	6.8
29–32	SAB	29	126	41	23	219
	Gestational weeks	4112	16 647	5977	3414	30 150
	Rate/1000 GW	7.1	7.6	6.9	6.7	7.3
33–36	SAB	13	69	24	14	120
	Gestational weeks	1620	6770	2915	1440	12 745
	Rate/1000 GW	8.0	10.2	8.2	9.7	9.4
≥37	SAB	5	16	9	5	35
	Gestational weeks	519	1515	766	611	3411
	Rate/1000 GW	9.6	10.6	11.7	8.2	10.3
Age-Standardized rate/1000 GW		7.2	7.3	6.5	9.0
Age-Standardized rate difference		0.0	[ref]	−0.8	1.7
(95% CI)		−1.6, 1.5		−2.0, 0.6	−0.2, 3.6
Age-Standardized rate ratio		0.99	[ref]	0.90	1.23
(95% CI)		0.80, 1.23		0.73, 1.09	0.99, 1.54

^aFrom the first imputation dataset.