The effects of Norplant-2 rods on clinical chemistry in Singaporean acceptors after 1 year of use: haemostatic changes.

A longitudinal study of coagulation parameters was carried out on 100 Singapore acceptors using the levonorgestrel subdermal implants Norplant-2 rods for contraceptive purposes. At the end of 1 year of use, results from this on-going study indicates that these acceptors have an enhanced potential for hypercoagulation with a significant shortening of their prothrombin time and activated partial thromboplastin time. They also have an increased predisposition to thrombosis as evidenced by significant increases in platelet count and aggregability. A number of other parameters achieved statistically significant differences by the end of one year but since the results were within the normal accepted range, they were therefore unlikely to be of much clinical importance.