Abnormal folate metabolism as a risk factor for first-trimester spontaneous abortion

OBJECTIVE: To assess the potential role of folic acid in early pregnancy loss by measuring homocysteine (hcy) levels in healthy, pregnant women who present with a current first-trimester miscarriage. STUDY DESIGN: This was a cross-sectional analysis comprising 13 patients aged 18-31 years old who had a scheduled dilatation and curettage for a first-trimester miscarriage. The controls were 15 patients of similar maternal age presenting for a first-trimester prenatal care visit. Following completion of a 21-item, structured questionnaire, patients were excluded from the study if they had any known risk factors for a first-trimester miscarriage. The remaining patients provided blood samples for measurement of homocysteine and red blood cell folate. Cases and controls were compared using a standard 2-sample t test. In order to detect a clinically relevant 2.3 μmol/L difference in homocysteine levels, 11 cases and 8 controls were needed. RESULTS: The mean hcy level in cases (5.8 μmol/L) vs. controls (5.7 μmol/L) was not significantly different (p = 0.83), and all individual values fell within the normal range expected in pregnant women. Red blood cell folate levels (cases = 586 ng/mL, controls = 611 ng/mL) were also not significantly different (p = 0.72), and no cases of folate deficiency were detected. Maternal age (cases = 26, controls = 25) and gestational age (cases = 8.8 weeks, controls = 8.4 weeks) were similar between the 2 groups. CONCLUSION: In this community-based pilot study, abnormal folate metabolism was not an apparent risk factor for spontaneous first-trimester pregnancy loss.