Efeitos dos contraceptivos hormonais orais de baixa dosagem estrogênica nas taxas de folato intra-eritrocitário

purpose: to study the effects of low-dose oral hormonal contraceptives (ohc) (<30 mg of ethynylestradiol) on the intraerythrocytic folate levels. methods: this was a prospective transversal study with 95 patients treated in the family planning clinic of unifesp (federal university of s？o paulo). the control group (condom group) consisted of patients using condom as their exclusive contraceptive method during the last 12 months, and the study groups consisted of patients using low-dose oral hormonal contraceptives, in the following way: ohc 3 group (three to six months of use), ohc 6 group (six to twelve months of use) and ohc 12 group (more than twelve months of use). intraerythrocytic folate was determined by the ionic capture method. analysis of variance and c2 test were used for statistical analysis. results: the condom group showed a rate of 44% of patients with folate lower than 186.0 ng/ml and the users of low-dose oral contraceptives showed a rate of 32% (ohc 3 group), 16% (ohc 6 group) and 31% (ohc 12 group). we did not find in the group using low-dose oral contraceptives a significant reduction in the average level of intraerythrocytic folate compared to the control group and there was no statistically significant difference (p=0.28) regarding time of use. conclusion: we observed reduced levels of intraerythrocytic folate in a significant number (44%) of patients not using low-dose oral hormonal contraceptives. their rates were similar to the lower limit considered to be normal by most authors, which points to a basal folate deficiency in the studied group. we did not observe any alteration in the level of intraerythrocytic folate in patients using low-dose oral hormonal contraceptives.