TABLE 2.
Associations between serum folate and vitamin B-12 concentrations and clinical outcomes after assisted reproduction in 100 women (154 initiated cycles) from the Environment and Reproductive Health Study (2007–2013)1
| Implantation |
Clinical pregnancy |
Live birth |
||||
| Quartile (minimum–maximum) | Cases/cycles, % | RR (95% CI) | Cases/cycles, % | RR (95% CI) | Cases/cycles, % | RR (95% CI) |
| Serum folate, ng/mL | ||||||
| Q1 (9.7–16.5) | 22/45 (48.9) | 1.00 (ref) | 18/45 (40.0) | 1.00 (ref) | 14/45 (31.1) | 1.00 (ref) |
| Q2 (16.6–20.2) | 20/35 (57.1) | 1.23 (0.85, 1.77) | 15/35 (42.9) | 1.02 (0.62, 1.67) | 10/35 (28.6) | 0.77 (0.38, 1.54) |
| Q3 (20.3–26.3) | 23/39 (58.9) | 1.23 (0.90. 1.69) | 22/39 (56.4) | 1.35 (0.90, 2.02) | 17/39 (43.6) | 1.19 (0.68, 2.09) |
| Q4 (26.4–154.2) | 22/35 (62.9) | 1.31 (0.89, 1.93) | 21/35 (60.0) | 1.50 (0.98, 2.32) | 18/35 (51.4) | 1.62 (0.99, 2.65) |
| P-trend | 0.26 | 0.04 | 0.01 | |||
| Serum vitamin B-12, pg/mL | ||||||
| Q1 (162–438) | 25/43 (58.1) | 1.00 (ref) | 20/43 (46.5) | 1.00 (ref) | 12/43 (27.9) | 1.00 (ref) |
| Q2 (439–534) | 23/46 (50.0) | 0.89 (0.62, 1.28) | 20/46 (43.5) | 0.92 (0.61, 1.39) | 16/46 (34.8) | 1.19 (0.67, 2.10) |
| Q3 (535–701) | 15/32 (46.9) | 0.82 (0.53, 1.27) | 14/32 (43.8) | 0.91 (0.57, 1.46) | 11/32 (34.4) | 1.13 (0.57, 2.24) |
| Q4 (702–2176) | 24/33 (72.7) | 1.31 (0.95, 1.80) | 22/33 (66.7) | 1.43 (0.98, 2.08) | 20/33 (60.6) | 2.04 (1.14, 3.62) |
| P-trend | 0.03 | 0.01 | 0.008 | |||
1
All analyses were conducted by using generalized estimating equations with binomial distribution and log link function with adjustment for age (continuous), BMI (continuous), and race (white, other). Tests for trend across quartiles were conducted by using a variable with the median serum concentration in each quartile as a continuous variable. Q, quartile; ref, reference.