The Birth Control Pill and the Questions Around It

The birth control pill is among the most widely used forms of reversible contraception in Canada. Most versions combine two synthetic hormones, an oestrogen and a progestin, taken daily to suppress ovulation and thicken cervical mucus. When taken consistently and correctly it is considered highly effective at preventing pregnancy, although effectiveness with typical use is lower than with perfect use.

Questions about the pill circulate widely in wellness circles and online. This article sets some of the commonly raised points beside the general state of knowledge.

Reported side effects

Like all medications, the pill carries a range of possible effects. Commonly reported ones include nausea, breast tenderness, headaches and changes in bleeding patterns. Product information and clinical reviews also mention mood changes and shifts in libido among reported effects, though the evidence for any single effect is mixed, and many users report no change at all. Combined hormonal methods are also associated with a small increase in the risk of blood clots, which prescribers discuss with patients individually.

People also use the pill for reasons other than contraception, such as heavy periods or acne, which is one reason experiences differ so sharply from person to person.

Nutrients and the pill

Some small studies suggest that hormonal contraceptives may lower blood levels of certain B vitamins, as well as minerals such as zinc and copper and vitamin C. Whether these differences matter in practice is disputed, since most studied users stay within normal ranges.

Interactions with other substances

Several medicines and supplements are known to interact with oral contraceptives. Examples include certain anti-seizure drugs, some antibiotics such as rifampin, and the herbal product St. John's wort, which can lower hormone levels. Pharmacists and prescribers are the usual sources for individual interaction questions, and not every antibiotic or antidepressant carries the same effect.

Animals, water and the environment

Ethical points are also raised. Drug development typically includes animal testing before human trials, a reality that troubles some vegan and vegetarian users. Synthetic oestrogens excreted by users, along with other sources, have been detected in waterways, and research has linked such compounds to reproductive changes in fish and amphibians. How much the pill itself contributes compared with other sources is still debated.