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Table 4 Variation of BC risk associated with full-term pregnancies and incomplete pregnancies according to location of the truncating mutation in BRCA1.

From: Variation in breast cancer risk associated with factors related to pregnancies according to truncating mutation location, in the French National BRCA1 and BRCA2 mutations carrier cohort (GENEPSO)

Reproductive factors Location of truncating mutation in BRCA1mutation carriers
  Outside LR1 (16,690 person-years of follow-up) In LR1 (5,367 person-years of follow-up)
  Person-yearsa No. of casesa HR 95% CI P value Person-yearsa No. of casesa HR 95% CI P value
Parityb           
   Nulliparous 10,911 21 1.00    3,378 9 1.00   
   Parous 5,779 145 1.42 0.77-2.63   1,989 34 0.27 0.13-0.55 <10-3
No. of full-term pregnanciesb           
   0 10,911 21     3,378 9 1.00   
   1-2 4,218 108 1.63 0.88-3.05   1,354 23 0.32 0.15-0.68 <10-3
   ≥3 1,546 36 0.96 0.48-1.94   635 11 0.20 0.08-0.49 <10-3
Full-term pregnancies by attained ageb           
   Nulliparous 10,911 21 1.00    3,378 9 1.00   
   Before age 40 4,325 81 1.36 0.72-2.56   1,501 23 0.33 0.16-0.68 <10-3
   After age 40 1,439 63 1.49 0.70-3.19   488 11 0.21 0.09-0.51 <10-3
Incomplete pregnancies c           
   Never 14,247 92 1.00    4,419 23 1.00   
   Ever 2,404 73 1.43 0.98-2.07 0.06 948 20 0.95 0.47-1.96  
No. of incomplete pregnancies c           
   0 14,247 92 1.00    4,419 23 1.00   
   1-2 2,254 66 1.36 0.93-2.00   820 16 0.82 0.39-1.73  
   ≥3 150 7 2.59 1.24-5.40 0.01 128 4 2.05 0.48-8.76  
Type and length of incomplete pregnancies c           
   No incomplete pregnancies 14,204 92 1.00    4,419 23 1.00   
   Induced abortion only 1,279 40 1.49 0.95-2.36 0.08 431 5 0.65 0.21-2.00  
   Miscarriage with length ≤3 months 924 28 1.33 0.79-2.26   428 13 1.25 0.56-2.81  
   Miscarriage with length >3 months 153 4 1.12 0.35-3.59   46 2 1.52 0.18-12.5  
  1. aNot including missing data. bAdjusted for menopausal status (yes, no) and oral contraceptives (never, ever). cAdjusted for parity (0, 1, 2, ≥3), menopausal status (yes, no) and oral contraceptives (never, ever). HR, hazard ratio; CI, confidence interval.