Chapter 62 Birth Control 1

Birth Control Interfering with the reproductive process at any step from gametogenesis to nidation (implantation of a fertilized ovum) 2

3

Selecting a Birth Control Method Consider: Effectiveness Safety Personal preference 4

Fig. 61-1. Percentage use for birth control methods, United States, 2002. Note: The segment labeled “other methods” refers to Norplant (no longer used), Lunelle, contraceptive patches, spermicides, cervical caps, female condoms, and other techniques. 5

Oral Contraceptives Mechanism – inhibits ovulation Classification (two main categories) Combination oral contraceptives (OCs) Estrogen and progestin Progestin-only OCs Three major subgroups of combination OCs Monophasic Biphasic Triphasic 6

Combination Oral Contraceptives – Adverse Effects Thromboembolic disorders- THIS IS WHY SMOKERS OVER 35 SHOULDN’T USE THEM Hypertension Abnormal uterine bleeding Benign hepatic adenoma Glucose intolerance 7

8

Noncontraceptive Benefits of OCs Decrease the risk of ovarian cancer, endometrial cancer Do not increase or decrease risk of breast cancer in average risk women May decrease risk of ovarian cysts, pelvic inflammatory disease, benign breast disease Benefit those with iron deficiency anemia, and acne Favorable effect on menstrual cycles Reduced cramps; lighter, shorter, and more predictable flow 9

Combination Oral Contraceptives – Drug Interactions Drugs and herbs that reduce the effects of OCs Rifampin- for treating TB Ritonavir- protease inhibitor for HIV Troglitazone Antiepileptic drugs- consider non-hormonal contraception St John’s wort 10

What to do about a missed pill? If pill missed in first week: take one ASAP and then continue with the pack. Back-up birth control for 7 days If 1 or 2 pills missed during 2nd or 3rd week: take one ASAP and then skip placebo week If 3 or more missed during 2nd or 3rd week: same as for missing 1 or 2 pills, but use back-up birth control for a week

Combination Oral Contraceptives – Drug Interactions Drugs whose effects are reduced by OCs Warfarin Insulin Oral hypoglycemics Drugs whose effects are increased by OCs Theophylline Imipramine Drugs that elevate potassium should be avoided by patients on yasmin or Yaz- these COCs use drospirenone (aldosterone antagonist) as a progestin 12

Combination Contraceptives with Novel Delivery Systems Transdermal contraceptive patch (OrthoEvra)- contains both estrogen and progestin, patch for 3 weeks, then 1 week off Contraceptive vaginal ring (NuvaRing) contains both estrogen and progestin, ring for 3 weeks, then on week off, if rings is out >3 hours, need back-up 13

Long-Acting Contraceptives Subdermal etonorgestrel implants (Implanon) progestin only Depot medroxyprogesterone acetate (MPA)- IM or subQ injection Intrauterine devices- a progestin one (Mirena) and a non-hormonal one (copper-T) Spermicides Barrier devices Condoms – male and female Diaphragm 14

Drugs for Medical Abortion Mifepristone (RU 486) with misoprostol Mifepristone blocks uterine progesterone receptors Must be administered in first 7 weeks after conception to be effective Adverse effects Bleeding Cramping Nausea Vomiting Diarrhea Headache 15

Drugs for Medical Abortion Methotrexate with misoprostol Prostaglandins: misoprostol, carboprost, dinoprostone 16

Emergency Contraception Contraception implemented after intercourse Following assault, failed contraception, or failure to use contraception Plan B One-Step: one high-dose (1.5 mg) tab of levonorgestrel within 72 hours Plan B 2 high-dose tablets of levonorgestrel (progestin) 1 tablet within 72 hours and another 12 hours later Alternatives to Plan B (ulipristal acetate- progestin agonist/antagonist) 17