Serum hyaluronic acid levels during pregnancy and labor.

OBJECTIVE: To study the changes in concentrations of serum hyaluronic acid in uncomplicated human pregnancies. METHODS: We determined the concentrations of serum hyaluronic acid, using a specific enzyme-linked immunosorbent assay, in 70 nonpregnant women, 250 women during their pregnancies, and 68 women at the time of parturition. Results were analyzed for statistical significance with Scheffé test for multiple comparisons. RESULTS: During pregnancy, mean (+/- standard deviation) serum hyaluronic acid levels were 11.4 +/- 4.5, 13.6 +/- 2.8, 20.6 +/- 1.5, and 46.9 +/- 7.9 ng/mL at 5-14 (n = 47), 15-26 (n = 46), 27-37 (n = 58), and 38-40 (n = 99) weeks' gestation, respectively. Pregnant women in labor (n = 68) had significantly higher levels (100.4 +/- 11.3 ng/mL) than did women at term but not in labor (P < .01). CONCLUSION: Maternal serum hyaluronic acid concentrations increase as pregnancy progresses and serum levels increase significantly at term. Hyaluronic acid may be associated with cervical ripening during parturition.