Which factor can reduce the effectiveness of Levonorgestrel ECP in women?

Obesity is a significant factor that can reduce the effectiveness of Levonorgestrel emergency contraception pills (ECPs). Research indicates that increased body weight, particularly a body mass index (BMI) of 25 or higher, can affect the pharmacokinetics and therefore the efficacy of hormonal contraceptives like Levonorgestrel. Higher body fat may influence the distribution and metabolism of the medication, potentially leading to reduced concentrations of the drug in the bloodstream, and ultimately less effective contraception.

The other factors listed do not have a well-documented influence on the effectiveness of Levonorgestrel ECPs. Age over 40, low blood pressure, and high cholesterol do not significantly impact the pharmacological action of the medication in the same way that obesity does. Thus, while all health conditions should be considered when administering care, obesity specifically has been shown through clinical research to correlate with decreased efficacy of Levonorgestrel.