Contraceptive pills ("the Pill") prevents pregnancy by altering the hormonal balance and it is this alteration that produces the many side effects. Some are minor and easily cured; others are serious and permanent. In pregnancy the vascular system of the body adjusts to accommodate a rapidly enlarging uterus. In the false pregnancy induced by the Pill the pelvic vascular system has an increased blood supply but there is no enlarging uterus to utilize this increase. In pregnancy the blood is altered and becomes more coagulable. This helps to promote easy clotting at the site of placental separation and so reduce the amount of bleeding following childbirth. The Pill duplicates the hyper-coagulable state, which makes the patient prone to intravascular thrombosis and stroke. The Pill raises the level of serum cholesterol and triglyceride, thus increasing the likelihood of coronary disease. The Pill has also been associated with migraine, severe emotional disturbance, reduced libido, cancers of the breast, cervix and liver; and minor side-effects such as thrush infections, nausea, breast tenderness, irregular bleeding, skin pigmentation, jaundice, weight gain, fluid retention, raised blood pressure, kidney disease, depression, urinary tract infection, inability to wear contact lenses, worsening of asthma, epilepsy, gall-bladder disease and raised blood sugar.
Research at the University of Southern California has shown that during the first six months of taking a birth control pill, the risk of developing cervical cancer trebles. After that period the risk reduces to double but rises again to treble if the contraceptive is taken for more than 12 years. The rate of cervical cancer in the US doubled between the early 1970s (when the Pill was beginning to be widely used) and the mid-1980s.
The risk of thrombosis is 5 in 100,000 for healthy women not on the Pill. This risk increases to 30 in 100,000 for those taking third generation versions of the Pill, which on the other hand reduce the risk of heart attack, according to research reported in 1995.