The folate status of reproductive-aged women in a randomised trial of a folate-fortified oral contraceptive: dietary and blood assessments

Objective: To assess the folate status of US women in a study of a folate-fortified oral contraceptive (OC) using the Short Folate Food Frequency Questionnaire and plasma and red blood cell (RBC) folate samples. Design: Sub-analysis from a multi-centre, randomised, double-blind, controlled contraceptive trial with assessments at baseline and 6 months. We calculated dietary folate equivalents (DFE) consumed and the proportion of participants meeting folate adequacy benchmarks. Setting: Eight centres in the USA. Subjects: Healthy women aged 18-40 years requesting contraception with no contraindications for OC use. Results: Overall, 385 participants were randomised to either a novel folate-fortified OC or a marketed OC. The 262 (68 %) participants compliant with the protocol were included in the analysis set. Baseline daily DFE consumption was 529.8 (SD 342.1) mu g and similar in both groups. At follow-up, the fortified OC group had higher intake than the conventional OC group (1225.9 (SD 346.2) mu g compared with 500.6 (SD 361.2) mu g). Mean plasma folate level increased from 44.5 (SD 17.2) to 55.8 (SD 21.1) nmol/l. Mean RBC folate level increased from 996.7 (SD 369.8) to 1311.9 (SD 436.0) nmol/l. The proportion meeting selected folate adequacy benchmarks increased in the fortified OC group (P< 0.001). Conclusions: Lack of adequate folate intake in reproductive-aged women from dietary sources or supplements alone suggests the need for novel approaches. Use of folate-fortified OC ensures adequate folate levels and meeting of folate benchmarks.