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Content Update

November 26, 2019

New Combined Hormonal, Intravaginal Ring for Long-acting Reversible Contraception (LARC): In 2018, the U.S. Food and Drug Administration (FDA) approved segesterone acetate and ethinyl estradiol (Annovera) for pregnancy prevention in females of reproductive age. The combination product is a contraceptive vaginal system that can be self-administered (21 days) and removed (7 days) each month for up to one year. This system has precautions, contraindications, and side effects similar to other combined hormonal contraceptives.

CHAPTER SUMMARY FROM THE PHARMACOTHERAPY HANDBOOK

For the chapter in the Wells Handbook, please go to Chapter 30. Contraception.

KEY CONCEPTS

KEY CONCEPTS

  • image The attitude of the patient and sexual partner toward contraceptive methods, efficacy rate, the reliability of the patient in using the method correctly (which may affect the effectiveness of the method), noncontraceptive benefits, and the patient’s ability to pay must be considered when selecting a contraceptive method.

  • image Patient-specific factors (eg, frequency of intercourse, age, smoking status, and concomitant diseases or medications) must be evaluated when selecting a contraceptive method.

  • image Adverse effects or difficulties using the chosen method should be monitored carefully and managed in consideration of patient-specific factors.

  • image Accurate and timely counseling on the optimal use of the contraceptive method and strategies for minimizing sexually transmitted diseases (STDs) must be provided to all patients when contraceptives are initiated and on an ongoing basis.

  • image Emergency contraception (EC) may prevent pregnancy after unprotected intercourse or when regular contraceptive methods have failed.

Unintended pregnancy is a significant public health problem. In the United States, approximately 6 million females become pregnant each year.1 The most recent data reveal that 37% of pregnancies are unintended, with the highest rates occurring in women aged 20 to 34 years.1 However, teen pregnancy rates are still an issue and slow to decline; teen births account for 11% of all the births in the United States.1 About half of all unintended pregnancies end in abortion, and 40% occur in sexually active couples who claim they used some method of contraception.1 If the goal of contraception—for pregnancies to be planned and desired—is to be realized, education on the use and efficacy of contraceptive methods must be improved.

ETIOLOGY AND PATHOPHYSIOLOGY

Comprehension of the hormonal regulation of the normal menstrual cycle is essential to understanding contraception in women (Fig. 79-1). The cycle of menstruation begins with menarche, usually around age 12 years, and continues to occur in nonpregnant women until menopause, usually around age 50 years. Factors such as race, body weight, medical conditions, and family history can affect the menstrual cycle.2,3 The cycle includes the vaginal discharge of sloughed endometrium called menses. The menstrual cycle comprises three phases: (1) follicular (or preovulatory), (2) ovulatory, and (3) luteal (or postovulatory).

FIGURE 79-1

Menstrual cycle events, idealized 28-day cycle. (FSH, follicle-stimulating hormone; ...

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