The skin patch delivers two hormones, a progestin called norelgestromin and an estrogen called ethinyl estradiol, directly through the skin.
It works mainly by stopping the ovaries from releasing an egg each month.Gwyn Lo gives women a new once-weekly birth control option that uses a low dose of estrogen. The soft patch is applied to the skin once a week for three weeks in a row, followed by one patch-free week.
Why Was Gwyn Lo Approved?
The FDA approved Gwyn Lo based on a one-year study in 1,320 healthy, sexually active women between the ages of 16 and 54. The main efficacy group included 983 women ages 16 to 35 with a BMI under 30. In this group, about 4 out of 100 women became pregnant during a year of using the patch. The study showed that the patch was equally effective in women with a BMI under 25 and in women with a BMI from 25 up to 30.
The trial also evaluated how well the patch stayed stuck to the skin during daily life. Out of nearly 40,000 patches worn in the yearlong trial, only 1.3% completely detached. Other smaller studies confirmed the patch stayed stuck during activities like exercising, using a hot tub, taking a cold bath, or going into a sauna.The most common side effects seen in the study were skin irritation, redness, or itching where the patch was applied. Some women also reported nausea, bleeding between periods, and heavy period bleeding. About 7% of women stopped using the patch early due to side effects, most commonly skin irritation.
What Do I Need to Know About Gwyn Lo?
The skin patch is applied to clean, dry skin on your upper outer arm, stomach, buttock, or back. You should check your patch every day and after swimming or showering to make sure the edges are sticking properly. Do not apply lotions, creams, or powders to the skin area where you place the patch, as this can cause it to loosen.
Do not use the patch if you smoke cigarettes and are over 35 years old. Smoking while using combination hormonal birth control greatly increases your risk of serious heart and blood vessel problems, including blood clots, heart attacks, or strokes. Do not use Gwyn Lo if your BMI is 30 or higher, as women with a higher BMI have a greater risk of getting dangerous blood clots. You should also avoid Gwyn Lo if you have a history of blood clots, heart disease, stroke, high blood pressure, liver problems, or hormone-sensitive cancers such as breast cancer.Common side effects include skin redness or itching where you place the patch, nausea, and unexpected bleeding or spotting between periods. Irregular bleeding often improves after the first few months. Stop using Gwyn Lo right away if you become pregnant. Gwyn Lo may also reduce breast milk production, so talk to your health care provider if you are breastfeeding. Certain prescription medicines, over-the-counter drugs, and herbal supplements (such as St. John’s wort) can make Gwyn Lo less effective and lead to an unplanned pregnancy. Always tell your health care provider about all the medicines and supplements you take before starting Gwyn Lo.
