Lecture Notes, Biology 203, Human Sexuality and Reproduction

Contraception, Sterilization and Abortion, Part 2

  1. Hormonal contraceptives
    1. Action of hormones
      1. Estrogen primarily inhibits ovulation (decreases LH and FSH), but also causes changes in the endometrium that make it less receptive to implantation, and inhibits ovum transport
      2. Progestin also inhibits ovulation, but also thickens cervical mucus, changes secretions in Fallopian tubes, and reduces the chance of implantation
      3. The lower the concentration of estrogen, the fewer side effects, since most are estrogen-related
    2. Combined hormonal contraceptive pills (most common type of birth control pills)
      1. Contain both estrogen and progestin in pills to be taken orally
      2. Early types of pills had 21 pills with equal amounts of hormones, with or without 7 pills with no hormones
      3. Sequential (or tricyclic) pills (see graph) have varying amounts of hormones to more closely mimic natural hormone production, allowing lower concentrations of hormones to be used
      4. Require the ability to remember to take the pills regularly every day
    3. Combined hormonal contraceptive patches and vaginal rings
      1. Contain both estrogen and progestin that diffuse from the patch or ring continuously
      2. Require a prescription, but the woman can change the patches or rings herself
      3. Each patch is left on 7 days--after three weeks/patches, no patch is used for a week, during which the woman menstruates--then a new patch sequence begins
      4. Vaginal rings (NuvaRing) are inserted into the vagina (no special location required) and left there for three weeks, and then removed for a week for menstruation--then a new ring is inserted
      5. Rings can be left in the vagina for up to four weeks, but after that they are no longer effective and should be removed.
      6. If the rings come out, they can be washed and reinserted if no more than three hours have elapsed
      7. Most women are able to conceive within 3 months after ceasing to use patches or rings
      8. Failure rate is about 3/1000 for both patches and rings
    4. Advantages of combined hormonal contraceptives
      1. Extremely effective
      2. Offer woman control over fertility and timing of menstruation
      3. Safe for most women (but see below)
      4. Women can take them for many years with no breaks required
      5. Effects are reversible (average time to conceive 3 months)
      6. Reduction of menstrual pain and cramps, ovulatory pain
      7. Reduced incidence of ovarian cysts (by 80-90%), anemia, PID, ovarian and endometrial cancer, ectopic pregnancies (not associated with melanomas)
      8. Variable effect on PMS--worsens in some women, improves in others
    5. Disadvantages of combined hormonal contraceptives
      1. Pills must be taken daily (requires good memory, regular schedule)
      2. Expense may be high, depending on where the contraceptive is prescribed and the type
      3. Menstrual cycle changes may be disconcerting
      4. May have estrogen-related side effects: nausea, headaches, tender breasts, depression, acne, etc.
      5. Estrogen may increase risk of blood clotting, cause slight increase in blood pressure
      6. Slight increase in risk of breast cancer (esp. after 10 years) and cervical cancer (may be secondary to increased chance of STD's, which may be secondary to increased number of sexual partners
    6. Contraindications (see list)
      1. Women with history of cardiovascular disease (heart attack, stroke, etc.) or clotting disorders should use some other form of birth control
      2. Women with history or close relatives with history of breast cancer should use some other form of birth control
      3. Women with chronic disease related to function of some major organ should consider using some other form of birth control
    7. Danger signs that should be noted by women using combined contraceptives
      1. Severe pain in legs, chest, or abdomen
      2. Severe unexplained headaches
      3. Unexplained loss of vision
      4. Reaction: should see physician promptly, stop using CC method, use some other form of contraception
    8. Women who are over 35 and smoke should use some other form of contraception (see table)