Table 4.

Relationship between Reproductive Status and Spontaneous Abortion in the Jinchang Cohort Study.

Variables	N *	Number of Spontaneous Abortions								rs	p
		1		2		3		≥4
		n #	%	n	%	n	%	n	%
Number of pregnancies
1	5246	39	0.74	0	0.00	0	0.00	0	0.00	0.190	0.000
2	7228	585	8.09	20	0.28	0	0.00	0	0.00
3	5731	312	5.44	202	3.52	0	0.00	0	0.00
4	3659	143	3.91	66	1.80	75	2.05	8	0.22
≥5	4049	121	2.99	84	2.07	54	1.33	76	1.88
Total	25,913	1200	4.63	372	1.44	129	0.50	84	0.32
Age at primary birth, years
<25	15,944	502	3.15	154	0.97	30	0.19	0	0.00	0.092	0.000
25~	8922	554	6.21	158	1.77	75	0.84	37	0.41
30~	657	76	11.57	28	4.26	18	2.74	22	3.35
≥35	249	10	4.02	2	0.80	6	2.41	0	0.00
Total	25,772	1142	4.43	342	1.33	129	0.50	59	0.23
Age at menarche, years
<12	1943	128	6.59	32	1.65	9	0.46	8	0.41	−0.016	0.032
12~	12,260	673	5.49	200	1.63	72	0.59	58	0.47
15~	9960	356	3.57	116	1.16	42	0.42	18	0.18
18~	1750	43	2.46	24	1.37	6	0.34	0	0.00
Total	25,913	1200	4.63	372	1.44	129	0.50	84	0.32
Age at last pregnancy, years
<25	6333	269	4.25	42	0.66	9	0.14	0	0.00	0.061	0.000
25~	12,540	599	4.78	196	1.56	66	0.53	19	0.15
30~	4501	206	4.58	80	1.78	30	0.67	40	0.89
35~	2032	92	4.53	36	1.77	24	1.18	11	0.54
40~	372	13	3.49	8	2.15	0	0.00	0	0.00
≥45	63	3	4.76	2	3.17	0	0.00	6	9.52
Total	25,841	1182	4.57	364	1.50	129	0.50	76	0.29
Number of artificial abortions
0	13,608	791	5.81	308	2.26	111	0.82	61	0.45	−0.129	0.000
1	7811	324	4.15	46	0.59	15	0.19	19	0.24
2	3583	72	2.01	18	0.50	0	0.00	4	0.11
≥3	911	13	1.43	0	0.00	3	0.33	0	0.00
Total	25,913	1200	4.63	372	1.44	129	0.50	84	0.32

* The times of pregnancies–the times of artificial abortions; ^# The times of spontaneous abortions.