Controversies in family planning: are all oral contraceptive formulations created equal?

Question: I have a physician friend who believes that generic birth control pills are less efficacious than brandname equivalents. He is fairly convinced of this, although he admits that it is based on several anecdotal experiences. I have never heard of any evidence to suggest that this is true. I think he may be misled. This is frustrating because he insists that all patients at the abortion clinic he runs get brand-name prescriptions only, which can be unaffordable. Is there any research that indicates for or against this idea? Respondent 1: Generics have to be “bioequivalent,” which means they have to include the same amount of active medication as the branded formulations. For oral contraceptives (OC), the pharmaceutical company is considered to have reached bioequivalence if the amount of steroid in its formulation is within 20% of the amount of steroids in the branded OC. So theoretically, there could be 20% more or less active hormone in the generic pills than the branded OC. That being said, even within branded OCPs, from batch to batch, there only has to be agreement within 20%, so if someone is on the edge of needing more hormone and there is a batch that has 18% less hormone, they might be at increased risk for pregnancy. Respondent 2: Generic medications need to demonstrate average serum equivalency of 80–125% over the month compared to the original medication. They do not have to demonstrate efficacy with separate studies. They are subject to the same requirements that the pills contain the stated amount of medication as brand-name medications, but with the carriers and other ingredients, serum levels can vary within that range. Different brands and generics may lead to varying serum levels, so problems can arise when you switch back and forth from different agents. Efficacy studies do not find a difference, and we would expect missing pills to trump a small serum level difference. I, and the contraception experts I know, support using the pill that is most economical and easy to obtain for the patient. I also support giving a patient the pill she prefers if she has a preference.