CIRCULATING HYALURONIC-ACID IN NONPREGNANT, PREGNANT, AND POSTPARTUM GUINEA-PIGS - ELEVATED LEVELS OBSERVED AT PARTURITION

OBJECTIVE: Dilatation of the uterine cervix at parturition is associated with an increase in cervical hyaluronic acid content. The objective is to test the hypothesis that circulating hyaluronic acid is increased at parturition. STUDY DESIGN: Serum hyaluronic acid levels from nonpregnant (n = 5), pregnant (n = 13), and postpartum (n = 4) adult Hartley guinea pigs were determined with a radiometric assay that utilizes iodine 125-labeled hyaluronic acid-binding protein. Results were analyzed for statistical significance with Student's paired t test and regression analysis. RESULTS: The serum hyaluronic acid level in nonpregnant animals was 238 +/- 88 ng/ml (mean +/- SEM). During pregnancy, serum hyaluronic acid levels were 127 +/- 12 and 126 +/- 34 ng/ml at 25 and 50 to 63 days' gestation, respectively. At parturition, hyaluronic acid levels increased fivefold to 765 +/- 111 ng/ml (p < 0.001). Hyaluronic acid levels returned to antepartum values 2 days post partum (153 +/- 27 ng/ml). There was no significant difference between arterial and venous levels. CONCLUSION: Circulating hyaluronic acid levels increase significantly at parturition in the guinea pig.