In comparison, absorption of nicotine from NRT is more gradual, leading to a lower likelihood of nicotine dependence.47 Additionally, nicotine is metabolized more rapidly during pregnancy due to enhanced activity of the CYP2A6 enzyme while pregnancy-related increases in blood volume further dilutes nicotine levels.48 Lower nicotine levels may lead to more nicotine withdrawal symptoms, making cessation more challenging.29 This evidence concerns the gene CYP2A6 and nicotine dependence.