The effectiveness of the contraceptive pill when used by heavier females was recently questioned.
However, after an investigation, the European Medicines Agency (EMA) said that body weight does not affect emergency contraceptives.
Last year a warning label was requested by the agency for Norlevo, which is the European version of Plan B to indicate that it may not be as effective in the prevention of pregnancy for women with a body mass index (BMI) above 25. This information was based on a study done during 2011 which indicated that heavier females who took products containing levonorgestrel, which prevents pregnancy after sexual intercourse, were four times more at risk of becoming pregnant than those women with lower BMIs.
After that recommendation was released, the regulatory agency undertook a review of other emergency contraceptives which contain ulipristal acetate or levonorgestrel, and discovered that the data in the previous studies was limited and not adequate to conclude that its effect was decreased with higher body weight. This does not imply that weight does not affect the effectiveness of the drug, but for now, the Committee for Medicinal Products for Human Use (CHMP) at the EMA has recommended the removal of the warnings from the labels by Norlevo. It also asked for emergency contraceptives to include study results showing the possibility of reduced effects in heavier females on the product inserts.
Although the European health authorities took action on Norlevo last year, the US Food and Drug Administration have not issued any warnings for Plan B. According to a professor of obstetrics, gynaecology and public health at Columbia University and senior medical adviser at Planned Parenthood Federation of America, Dr Carolyn Westhoff, it is not inevitable that the FDA will act on the available data. She said that professionals in the field have been considering the types of studies that could be done to obtain more data which would allow them to better understand the findings, but no further studies have been undertaken.
EMA has admitted that this type of data is not available yet, but stated that they have sufficient data to support the warning that was previously issued about weight.
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