Thrombosis is an event of blood clotting inside the blood vessels. It can be occur in vein as well as artery. It includes a long pathway of thrombus formation and deposition to blood vessels. This obstructs blood flow through circulatory system and thus reduce the supply of oxygen. Thrombosis is symptomatic. Redness or discoloration of body part is the main symptom of thrombosis. Thrombosis may lead to stroke and myocardial infarction.
Older CHC was tablet formation which contain low-dose of estrogen. There are mainly four low-dose combined hormonal contraceptive preparations.
While in current scenario, there are three CHC preparations available: drospirenon-containing pills (DRSPs), norelgestromin-containing transdermal patches (NGMNs) and etonogestrel vaginal ring (ETON).
Retrospective study was conducted in Oakland to determine the effect of these recent CHCs preparation with thrombotic events. More than half million of women were included in the study who were new users of recent CHCs. In this study, comparison was done using users of low dose older CHC preparations. It was found that women who were using recent CHCs were at increased risk of thrombosis and thromboembolism than who were using low dose older CHCs. Among the three recent CHCs, it was found that there was no increased risk among women who had used NGMN patch or ETON ring.