The combined oral contraceptive pill is a birth control method that includes a combination of an estrogen (oestrogen) and a progestin (progestogen). When taken by mouth every day, these pills inhibit female fertility. These pills were developed to prevent ovulation by suppressing the release of gonadotropins. Combined hormonal contraceptives inhibit follicular development and prevent ovulation as their primary mechanism of action.
Progestagen negative feedback and the lack of estrogen positive feedback on LH release prevent a mid-cycle LH surge. Inhibition of follicular development and the absence of a LH surge prevent ovulation.
Blood Clotting or Coagulation is a complex process by which blood forms clots. It is an important part of hemostasis, the cessation of blood loss from a damaged vessel, wherein a damaged blood vessel wall is covered by a platelet and fibrin-containing clot to stop bleeding and begin repair of the damaged vessel. Disorders of coagulation can lead to an increased risk of bleeding (hemorrhage) or obstructive clotting (thrombosis).
Venous thrombosis or blood clots in a vein occur when a person becomes immobilized and muscles are not contracting to push blood back to the heart. This stagnant blood begins to form small clots along the walls of the vein. This initial clot can gradually grow to partially or completely occlude or block the vein and prevent blood from returning to the heart. An analogy to this process is a slow moving river. Over time, weeds and algae start to accumulate along the banks of the river where the water flows more slowly. Gradually, as the weeds start to grow, they begin to invade the center of the river because they can withstand the pressure of the oncoming water flow.
The newer contraceptive birth control pills have double the risk of blood clots
FDA is reviewing the safety of newer birth control pills, its birth control investigation was announced shortly. The study published in BMJ is going to trouble doctors, patients and drug companies. In September, the agency said, “remains concerned about the potential increased risk of blood clots with the use of drospirenone-containing birth control pills.”
It is one of the largest studies to look at the risk in regards to venous thrombosis. The researchers stressed that women should consult their doctor before changing brands or formulas.
Blood clots can be particularly dangerous because once formed in a peripheral vein, usually in the leg, the clot can break free and travel to more sensitive parts of the body, such as brain or vital organs.
Medical records of about 1.3 million women...
were included in the study, with 30% of them never having used hormonal contraception, while nearly 70% having used some form of hormonal birth control.
Of the total, 4,307 cases of blood clots required treatment with (64%) as deep vein thrombosis (DVT), where a blood clot chokes circulation in a limb, causing a leg or arm to become swollen, stiff, or painful. 25% were blood clots in the lungs. Around 2% had blood clots that caused strokes. The older-generation pill that contains an estrogen and the progestin hormone levonorgestrel roughly doubled the risk compared to women not on any hormonal birth control.
The newer kinds of pills, which contain the progestin hormones drospirenone, desogestrel, or gestodene along with estrogen, doubled the risk again, making it six to seven times as high as women who weren’t using hormonal forms of birth control. On average, roughly 10 out of 10,000 women taking newer kinds of birth control pills had venous thrombosis within a year.
But experts say changing back to an older version of the pill may not be the smartest choice for all women. Philip C. Hannaford, MD, who is the Grampian Health Board chair of primary care at the University of Aberdeen in Scotland, says “It is important to have a range of different oral contraceptives available because some women tolerate one preparation better than another. This means that clinicians and women often chose to use combined oral contraceptives which do not contain levonorgestrel, and this seems a pragmatic and sensible thing to do given that the background risk of DVT is very low.”
Also women and their health care professionals have to take into account other factors, like medical history, family history and other risk factors such as smoking, alcohol consumption, weight and general health.