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) μg 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) μg compared with 500·6 (sd 361·2) μg). 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.