Table 2.

Fertility after appendicectomy compared with age matched controls according to Cox proportional hazards regression analysis of rate of first birth. Results compare average rates of first birth expressed as hazard ratios. Differences in birth rates according to diagnosis at operation were adjusted for year of birth and age at operation. Values are hazard ratios (95% confidence intervals); P values

Factor	No of women	Univariate analysis	Multivariate analysis
Diagnosis at operation:
Control	47 590	1.00	1.00
Normal appendix	3 126	1.48 (1.42 to 1.54); <0.001	1.48 (1.42 to 1.54); <0.001
Appendix not perforated	5 815	1.11 (1.07 to 1.15); <0.001	1.11 (1.07 to 1.15); <0.001
Perforated appendix	899	0.95 (0.87 to 1.03); 0.20	0.95 (0.88 to 1.04); 0.26
Year of woman’s birth:
Before 1960	11 404	1.00	1.00
1960-4	17 648	0.87 (0.85 to 0.89); <0.001	0.87 (0.84 to 0.89); <0.001
1965-9	23 421	0.82 (0.79 to 0.84); <0.001	0.82 (0.79 to 0.84); <0.001
After 1969	4 957	0.74 (0.70 to 0.78); <0.001	0.75 (0.71 to 0.79); <0.001
Age at operation (years):
<11	9 170	1.00	1.00
11	10 968	0.95 (0.92 to 0.99); <0.007	0.98 (0.94 to 1.01); 0.21
12	11 883	0.95 (0.92 to 0.98); <0.003	0.98 (0.95 to 1.01); 0.24
13	11 966	0.98 (0.95 to 1.02); 0.33	1.00 (0.97 to 1.03); 0.96
14	13 443	1.01 (0.97 to 1.04); 0.75	1.01 (0.98 to 1.05); 0.47