From: Drinking water nitrate and risk of pregnancy loss: a nationwide cohort study
 | Pregnancy to week 22a | First trimesterb | Second trimesterc | ||||||
---|---|---|---|---|---|---|---|---|---|
 | n = 83,575 (2,915 pregnancy losses) | n = 53,082 (1,481 pregnancy losses) | n = 82,004 (1,352 pregnancy losses) | ||||||
NO3- (mg/L) | Pregnancies (n (%)) | Pregnancy losses (n) | aHRd (95% CI) | Pregnancies (n (%)) | Pregnancy losses (n) | aHRd (95% CI) | Pregnancies (n (%)) | Pregnancy losses (n) | aHRd (95% CI) |
≤ 1 | 24,829 (29.7) | 831 | Ref (1) | 15,428 (29.1%) | 397 | Ref (1) | 24,717 (30.1) | 423 | Ref (1) |
> 1- ≤ 2 | 23,474 (28.1) | 829 | 0.97 (0.88, 1.07) | 15,263 (28.8) | 433 | 0.98 (0.86, 1.14) | 22,894 (27.9) | 363 | 0.91 (0.77, 1.06) |
> 2- ≤ 5 | 22,013 (26.3) | 781 | 1.00 (0.90, 1.10) | 13,983 (26.3) | 408 | 1.03 (0.89, 1.19) | 21,492 (26.2) | 351 | 0.95 (0.82, 1.10) |
> 5- ≤ 25 | 9,586 (11.5) | 346 | 1.04 (0.92, 1.18) | 6,011 (11.3) | 176 | 1.10 (0.92, 1.31) | 9,229 (11.3) | 156 | 0.98 (0.81, 1.17) |
> 25 | 3,673 (4.4) | 128 | 0.97 (0.81, 1.17) | 2,397 (4.5) | 67 | 1.03 (0.80, 1.34) | 3,672 (4.5) | 59 | 0.92 (0.70, 1.21) |