The Goal of Birth Control Is the Prevention of Pregnancy

Highly Effective Methods, i.e., Failure rate < 1%

Abstinence

• Abstinence involves refraining from intercourse

• Failure rate 0 %

Sterilization involves cutting and sealing gamete transport tubes

• Vasectomy– Cut and seal each vas deferens

• Tubal ligation– Fallopian tubes cut and sealed

• Failure rate < 1%

Birth Control Pills (OCs)

• Highly Effective: 0.1 failure rate (when used properly)

• Orally active synthetic estrogens and progestins

• Mechanism of Action:– Inhibition of LH/FSH & follicle growth– Inhibits midcycle LH/FSH surge & ovulation

• Risks: Heart disease, stroke, blood clots

Types of Oral Contraceptives

• Monophasic: All 21 active pills contain same amount of Estrogen/Progestin (E/P)

• Biphasic: 21 active pills contain 2 different E/P combinations (e.g., 10/11)

• Triphasic: 21 active pills contain 3 different E/P combinations (e.g., 6/5/10)

• Constant: Lybrel (Wyeth) www.noperiod.com

Combined OCs: Mechanism of Action

Suppress ovulation

Mechanism: Negative feedback of OCSteroids on LH & FSH

Hormonal Changes Following Oral Contraceptive Treatment

Which of the following are actions of the birth control pill?

A. Inhibits sperm production

B. Inhibits the midcycle LH & FSH surge

C. Inhibits ovulation

D. Blocks fertilization

Birth Control Patch (Ortho Evra)

Birth Control Patch (Ortho Evra)

• 1 ¾ “ sq patch that delivers synthetic progestin and estrogen through skin

• 3 wks of patch; one wk. w/o patch and a menstrual period occurs

• Mechanism: Prevents ovulation• Effectiveness: Highly effective (< 1%

failure rate)• Risks: Similar to BC pill; blood clots, heart

attack & stroke

Monthly Injectable: Lunelle

• Monthly injection containing E and P

• Mechanism: inhibits ovulation (same as

OCs)

• Highly Effective: 0.03% failure rate

• Risks: Irregular bleeding, moderate weight gain, headaches, mood swings. Risks of blood clots and stroke.

Vaginal Contraceptive Ring

Vaginal Contraceptive Ring: NuvaRing

• Soft, flexible, transparent plastic vaginal ring containing hormones similar to BC pills

• Mechanism: Prevents ovulation• Ring self-inserted into vagina.• After 3 weeks ring removed and m. period occurs.

On 4th week another ring inserted.• Or, a new ring can be inserted immediately after the

ring is removed and no menses occurs.• Effectiveness: Highly (0.1 - 1 % failure rate)• Adverse effects: vaginal discharge, nausea,

moderate wt. gain, headaches, vaginitis, slight risk of blood clots in legs or lungs.

Intra-Uterine Device

IUD

• Small plastic or metal device inserted into uterus by physician

• Interferes with implantation & fertilization

• Highly effective (< 2% failure rate)

• Risks: Pelvic inflammatory disease– Monofilament vs woven filament (Delkon Shield)

IUDs: Mechanisms of Action

Interfere with reproductive process before ova reach uterine cavity

Thicken cervical mucus

Interfere with ability of sperm to pass through uterine cavity

Change endometrial lining & inhibit implantation

IUDs act by:

A. Inhibiting ovulation

B. Blocking implantation of the embryo

Image Challenge

Q: What is the diagnosis?

1. Retained surgical clamp2. Uterine perforation3. Thanksgiving turkey4. Hermaphroditism5. Appendicitis

Image Challenge

Q: What is the diagnosis?

Answer:

2. Uterine perforation

The radiograph demonstrates an intrauterine device in the left upper quadrant, a consequence of migration or uterine perforation.Read More: New Engl J Med 356;4:397

Emergency Contraception: Plan B(morning after pill)

• High dose estrogen or progestin within 72 hr of unprotected intercourse and second dose 12 hr later

• Mechanism(s):– Potentially interferes with:

• Ovulation• Fertilization• Implantation

• Effectiveness: Reduces by 75% chance of pregnancy after unprotected sex

• Side effect: Nausea

Emergency Contraception: Plan B(morning after pill)

• After a long delay (and much controversy) the FDA approved the sale of Plan B pill for sale without prescription (OTC) – but only for women 18 years and older.

Question: Should Plan B be available to 17-year-olds OTC?

A. Yes

B. No

C. Undecided

Emergency Contraception: Plan B(morning after pill)

• Last April (4/22/09) the FDA approved the sale of Plan B to 17-year-olds OTC.

Progestin Implant: Norplant

• Six silastic tubes filled with progestin• Slow release; lasts five years• Mechanism of Action:

– Inhibits LH/FSH release (prevents ovulation)– Thickens cervical mucus; prevents sperm

penetration– Alters endometrium and blocks implantation

• Highly Effective: 0.1% fail rate• Risks: Unscheduled (breakthrough) bleeding

Norplant Implants: Mechanisms of Action

Suppress ovulation

Decrease tubal motility

Change endometrium

Thicken cervical mucus

Injectable: Depo-Provera

• I.m. injection every three months

• Mechanism of action same as Norplant

• Effectiveness: Highly; 0.3% failure rate

Less Effective Methods: Failure Rates 3 – 20%

• Diaphragm

• Cervical cap

• Male condom

• Female condom

• Spermicides

• Rhythm method

If the diaphragm is correctly placed, the back rim is below and behind the cervix, and the front edge of the rim is tucked up behind the pubic bone.

Abortifacient

• Antiprogestins: Ru 486– Progesterone receptor

antagonist– Typically given 5 days

with prostaglandin

Potential Male Contraceptives

• Hormone injection– Testosterone implant

(sc) every 4 mo plus– Progestin injection

every 3 mo.– Proved effective in

men but dosing regime needs to be improved

Potential Male Contraceptives

• Oral pill that works short-term

• Drugs that treat schizophrenia and high blood pressure inhibit ejaculation

• Work as contraceptive in male mice

• Not yet tested in humans

• Side effects: dizziness and drowsiness

• Pill at least 5 years away

(a) IUDs

(b) Female condom

(c) Spermicide

(d) Male condom

(e) Diaphragm

(f) Vaginal contraceptive ring

(g) Skin patch

(h) Plan B