The effects of Norplant® on clinical chemistry in Singaporean acceptors after 1 year of use: I. Haemostatic changes

Abstract

A longitudinal study of coagulation parameters was carried out on 100 Singaporean acceptors using the levonorgestrel subdermal implants NORPLANT® for contraceptive purposes. At the end of 1 year of use, results from this on-going study indicate that these subjects may have an increased predisposition to thrombosis as evidenced by significant increase in platelet count and aggregability. The results also show that NORPLANT® acceptors may have an enhanced potential for hypercoagulation - with a significant shortening of their Prothrombin Time and Activated Partial Thromboplastin Time and increases in Factors V and X. As previously documented, mean values for haemoglobin and haematocrit were significantly elevated by the end of 1 year. A number of other parameters achieved statistically significant differences by the end of 1 year but these were probably due to the large sample size involved and were therefore not likely to be of much clinical importance.