The contraceptive patch, such as Xulane or Twirla, offers a convenient method of birth control by delivering hormones through the skin. These patches release synthetic versions of estrogen and progestin, which work to prevent pregnancy. A common question for users is understanding how long these hormones remain in the body after the patch is removed.
How Hormones Enter the Body
The contraceptive patch utilizes transdermal delivery, releasing hormones directly through the skin and into the bloodstream. This method bypasses the digestive system, unlike oral contraceptives. Patches like Xulane contain norelgestromin (a progestin) and ethinyl estradiol (an estrogen), while Twirla contains levonorgestrel and ethinyl estradiol. The patch continuously releases these synthetic hormones, allowing for steady absorption into the systemic circulation.
How Hormones Are Eliminated
Once in the bloodstream, the synthetic hormones from the patch undergo metabolism, primarily in the liver, breaking them down into inactive substances called metabolites. These metabolites are then prepared for removal from the body.
The elimination rate of these hormones is described by their half-life, the time it takes for half of the substance to be cleared from the body. Ethinyl estradiol has an elimination half-life of approximately 17 to 28 hours. Norelgestromin has a half-life of about 17 to 45 hours. After patch removal, hormones continue to circulate and are gradually eliminated over several days. The inactive metabolites are primarily excreted through urine and feces.
Individual Differences in Clearance
Several factors influence how quickly hormones are cleared from an individual’s system. Metabolic rates vary among people due to genetic differences in liver enzymes, which are responsible for breaking down hormones. These variations affect how rapidly the synthetic hormones are processed.
Body weight and composition also play a role, as hormones may be stored in fatty tissues, potentially extending their presence in the body. The duration of patch use also contributes; prolonged use establishes a steady state of hormones, which then takes time to clear. Liver function is another factor, as impaired liver function could slow down metabolism and elimination processes, leading to a longer presence of hormones.
What Happens When You Stop Using the Patch
When the contraceptive patch is discontinued, the continuous supply of hormones stops, and the body’s hormone levels begin to decline as the remaining synthetic hormones are eliminated. This drop in hormone levels leads to withdrawal bleeding, which resembles a menstrual period. This bleeding typically occurs within a few days to a week after removing the last patch.
The return of the natural menstrual cycle varies among individuals but generally occurs within a few weeks to a few months after discontinuation. Fertility can return quickly once the synthetic hormones are cleared from the system. If pregnancy is to be avoided, another form of contraception should be initiated immediately upon stopping the patch.