Birth Control Pills: Be Aware Of New Generation Drug Risks
Oral contraceptives (OC) have been used since 1960 and remain the most common birth control method in many countries. When taken as recommended, their efficacy in avoiding pregnancy is close to 99.9 per cent.
Although doctors and users generally consider the safety as “good”, the newest and widely prescribed formulations known as 3rd and 4th generation pills are now under scrutiny due to their poorer safety profile compared with the 1st and 2nd generation.
Most OC products contain a combination of the two main female hormones involved in the menstrual cycle: oestrogen and progestin, the latter having the effects of progesterone. The common side effects are weight gain, acne, hair loss or growth, headache, breast tension, painful menstruation and irregular bleeding. In addition, all combination OC can, although very rarely, trigger potentially serious and even fatal side effects such as pulmonary embolism (blood clot formations within the veins, which can migrate to the lungs), stroke or heart attack.
The first formulation of the pill contained a high dose of oestrogen (ethinylestradiol). The second generation used a micro-dosage of the same oestrogen with levonorgestrel or norgestrel as progestin. In the ’90s, the third and then the fourth generation maintained (or further reduced) the micro-dosage of ethinylestradiol but brought in different progestin (desogestrel, gestoden and norgestimate for the 3rd generation and drospirenone for the 4th generation).
The development of these latest generations came about as an attempt to minimise the most frequent hormonal-induced side effects such as acne, headache and irregular bleeding. Unfortunately, according to the French Medicine Agency, no reliable study has clearly demonstrated any beneficial effect of these newer generations versus the first two. More importantly, these new generations have been found to be responsible for a higher incidence of venous thrombosis, pulmonary embolism and death.
Such serious side effects usually but not always occur within the first 6 months. Various risk factors include smoking, age (over 35 years old), being overweight and presence of inherited abnormalities in the coagulation system.
The higher risk of serious side effects with the newer generations was first demonstrated in 1995 in the UK and later, in 2001, following the publication in the British Medical Journal of a large study conducted in Denmark. The authors concluded that, compared with women not taking OC drugs at all, those receiving the first two generations had a risk multiplied by 3 and those getting the 3rd and 4th generations had a risk multiplied by 6.
Yet despite 10 years of clear-cut knowledge of the poorer safety profile, these newer agents are still more often prescribed than the first generations in most countries.
Last month in France, a 26-year-old woman who took a 3rd generation OC drug and suffered an invalidating stroke sued the product marketer as well as the French medicine agency for allegedly failing to inform about the risks of the newer OC drugs versus the previous generations. This high profile legal case has prompted the French Ministry of health to revoke the reimbursement of these products by the social security system and strongly recommend using the 1st or 2nd generation of OC as the first line approach for all women.
Existing scientific evidence should guide practitioners to first prescribe the safest oral contraceptives.
Dr Gerard Lalande is managing director of CEO-Health, which provides medical referrals for expatriates and customised executive medical check-ups in Thailand.
He can be contacted at gerard. [email protected].
