INDICATIONS FOR EMERGENCY METHODS
(1) Condom breakage or barrier method dislodged or torn during intercourse
(2) Refusal of a partner to use protection
(3) Exposure to possible teratogen, such as live vaccine, cytotoxic
drug, etc.
(4) Forced sexual contact
(5) Missed contraceptive pills: It is theoretically riskier when missed
at the beginning of a cycle and emergency contraception should be considered.
Even though the risk is extremely low at the end of the menstrual cycle,
a woman who has been raped or wants to avoid pregnancy for other reasons
may want to employ emergency contraception. This is a legitimate use
of the technique.
The probability of conception when emergency
contraception should be considered is often unclear or misunderstood.
the average fertile period for a woman lasts only six days per menstrual
cycle and ends the day she ovulates. Unprotected sex three days before
ovulation results in an estimated 15 percent pregnancy rate; one or
two days before ovulation, about 12 percent. Sperm can survive in the
female up to five days and the mature egg may be fertilized over a 24-hour
period. The time period from ovulation to implantation is about seven
days.
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RECOMMENDED
METHODS
(1) Combined Oral Contraceptives: Uses estrogen-progestin combinations
(ethinyl estradiol and norgestrel/levonorgestrel) - also known as the
Yuzpe regimen after Albert Yuzpe, whose research on high-dose estrogen
regimens led to the current treatment protocols. The efficacy of combined
regimens that contain a progestin other than norgestrel/levonorgestrel
has not been studied.
(2) The progestin-only minipill (levonorgestrel).
(3) The Copper-T 380 intrauterine device (IUD).
(4) Antiprogestins - Low doses of antiprogestin synthetic steroid RU 486
(mifepristone, Mifeprex) have been shown to be equally or more effective
than existing oral regimens for postcoital contraception. However, these
products are not readily available. |
Combined Oral Contraceptives
The FDA has reviewed the data on the Yuzpe regimen and concluded that
it is safe and effective. The American College of Obstetricians and
Gynecologists also reviewed the date and made a special recommendation
to its members that this regimen is underutilized and should be made
more widely available to patients seeking reproductive health care.
Treatment: The regimen consists of 2 doses of ethinyl estradiol (100 ug) and
levonorgestrel (0.5 mg). The first dose should be taken within 72 hours
of unprotected intercourse and the second 12 hours after the first dose
(see Table). It is equally effective whether initiated early or late
within the 72-hour window. However, consider the timing of the second
dose when administering the first. For example, a first dose at 3 in
the afternoon will mean a second dose at 3 in the morning.
The appropriate number of pills may be used
from different trade name birth control pill packages. Recently, a prepackaged,
dedicated product consisting of 4 pills (PREVEN) has beenn developed.
If 100 women have unprotected intercourse
during the second and third week of their cycle, the probability is
that eight will become pregnant. If the Yuzpe method is used, only two
women will become pregnant (a 75% reduction).
Side effects: Mainly gastrointestinal: nausea 50%, vomiting 20%. Taking the pills
with meals may reduce the risk of nausea, however, theoretically, this
may lower plasma hormonal levels and reduce contraceptive efficacy.
Less common side effects are heavy menses
and mastalgia. Withdrawal bleeding occurs within three weeks of treatment.
Thirty-eight percent bleed before their menstrual period is due. About
8% may be 4 or more days late.
Contraindications: Other than confirmed pregnancy, there are no absolute contraindications
to the emergency use of oral contraceptive combinations. Studies have
shown no evidence of harm to the developing fetus. Relative contraindications
include migraine with marked neurologic symptoms and preexisting venous
thromboembolic disease. Thrombotic episodes have been reported following
use of this regimen. Although it is not clear where these events were
actually related to hormone use, in these patients use of a progestin-only
pill or emergency IUD insertion is recommended. If the timing of exposure
makes the risk of pregnancy very slight, the safest course may be to
do nothing at all.
In England, where emergency contraception
has been used in over 4 million cases in 13 years, no statistically
significant increase in the rate of deep venous thrombosis has occurred.
Mechanism of action: Prevention
or delaying of ovulation may be the primary mechanism of drug action.
These hormones will not dislodge an implanted embryo. This is important
to convey to patients because it has obvious significance to anyone
whose religious beliefs prohibit interference with reproduction once
fertilization has taken place. Those who remain fearful about hormonal
side effects may prefer IUD insertion, or depending upon their likelihood
of pregnancy, no treatment at all.
Patients have not be shown to become dependent
on this means of contraception. Also, the nausea associated with high
dosages is significant enough to make them think twice about requesting
this intervention on a regular basis.
Agents Used
for Emergency Contraception
Ovral (white), Femenal
Norgestrel 0.50 + ethinyl
estradiol 50 ug
Number of pills: 2
LoOvral (white)
Norgestrel 0.30 + ethinyl estradiol 30 ug
Number of pills: 4
Levlen (light orange), Nordette (light orange),
Levora (white), Microgynon 30, Nordette, Rigevidon 21+7 (seven containing lactose)
Levonorgestrel 0.15 mg + ethinyl estradiol 30 ug
Number of pills: 4
Alese (pink)
Levonorgestrel 0.1 mg + ethinyl estradiol 20 ug
Number of pills: 5
Trilevlen (yellow), Triphasil (yellow), Tiivora
(pink)
Levonorgestrel 0.1 mg + ethinyl estradiol 30 ug
Number of pills: 4
Orvette (yellow)
Norgestrel 0.075
Number of pills: 20
Dedicated Products
Preven: Per dose: 2 blue pills, 100 ug of ethinyl estradiol, 0.50 mg levonorgestrel.
Plan B: Per dose: 1 white pill, no ethinyl estradiol, 0.75 mg levonorgestrel.
No of doses: 2 (two)
Timing of administration: First dose within 72 hours of unprotected
intercourse; second dose 12 hours later. The patient may wish
to time her first dose as not to wake up during the night to take
the second dose. Norgestrel contains two isomers, only one of
which (levonorgestrel) is bioactive. Thus, 0.05 mg norgestrel
is equivalent to 0.25 mg levonorgestrel.
(Red Brands: Philippine
Oral Contraceptives) |
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Management of Gastrointestinal Side Effects of Emergency Contraceptive
Medication
Nonprescription Drugs
Drug:
Meclizine hydrochloride
Dose:1-2 (25mg) tablets
Timing: 1 hr before first ECP dose; repeat if needed in 24 hr.
Drug: Diphenhydramine Hcl
Dose: 1-2 (25mg) tablets
Timing: 1 hr before first ECP dose; repeat as needed q 4-6 hr.
Drug: Dimenhydrinate
Dose: 1-2 (50mg) tablets or 4-8 tsps
Timing: 30 mins to 1 hr before 1st ECP dose; then q 4-6 hrs prn.
Drug: Cyclizine Hcl
Dose: 1 (50mg) tablet
Timing: 30 mins before 1st ECP dose; then repeat q 4-6 hrs prn.
Prescription Drugs
Drug:
Meclizine Hcl
Dose: 1-2 (25mg) tablets
Timing: 1 hr before 1st ECP dose; repeat prn in 24 hrs.
Drug: Trimethobenzamide HCL
Dose: 1 (250 mg) tablet or 200mg suppository
Timing: 1 hr before first ECP dose; then prn q 6-8 hrs.
Drug: Promethazine Hcl
Dose: 1 (25mg) tablet or suppository
Timing: 30 mins to 1 hr before 1st ECP dose; then prn q 8-12 hrs. |
Progestin Minipill
While somewhat less effective than combined preparations when used as
a regular birth control method, the progestin-only minipill may outshine
the former when it comes to emergency use. Not only is its efficacy thought
to be greater, but nausea and vomiting are significantly less common,
and it can be used even by women who cannot tolerate estrogen. The catch
is that the required dosage of levonorgestrel, 0.75 mg may be unavailable
in a single- or two-tablet format. In order to obtain postcoital protection,
a woman must ingest two doses of 20 tablets each of norgestrel 12 hours
apart, beginning within 72 hours of exposure. (Only half of the norgestrel
pill consists of levonorgestrel; hence, the necessity for 20 tablets.)
Faced with such an inconvenient and expensive regimen, most patients are
willing to overlook the gastrointestinal effects associated with the combined
preparations.
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Copper
T-380 A Intrauterine Device
The Copper-T IUD will prevent pregnancy up to five days following unprotected
intercourse. Although not suitable for all women, the device is significantly
more effective than either form of oral emergency contraception, reducing
the risk of pregnancy by 99%.
Mechanism of action: Not firmly established, depending on the timing of insertion, may
interfere with sperm transport or implantation. Because the method prevents
implantation, an IUD may be inserted up to five days after the earliest
estimated date of ovulation.
Side effects and risks are the same as those for IUD insertion at other times.
If left in place, it will provide continuous effective contraception for
up to 10 years. However, potential users should be carefully screened,
as insertion may not be advisable in women who have elevated risk for
PID or other sexually transmitted infections. Use is not recommended in
women who have been raped, as they may have been exposed to sexually transmitted
disease in the process. For women who are not at risk for STD, the health
risks associated with IUD use are very low.
Contraindications: Confirmed or suspected pregnancy is a contraindication to the IUD,
as presence of the device may cause spontaneous abortion, septic second-trimester
abortion, or premature delivery. |
Antiprogestins
RU 486 (Mifepristone)
Mifepristone inhibits ovulation and blocks
implantation by causing a delay in endometrial maturation. It causes an
actual regression of the corpus luteum in 50 percent of women when given
in the middle or late luteal phase. Only mifepristone is effective once
implantation has occurred, actually interrupting an early pregnancy.
In trials, RU 486, given as a single 600-mg dose
within 72 hours after unprotected intercourse, was 100% effective as an
emergency contraceptive. Other doses, 50 mg or 10 mg, given as a single
dose within five days of unprotected sex were also effective in decreasing
pregnancy rate by 85 %.
Dose: 10 mg, 50 mg, 600
mg
Timing of first dose after intercourse:
0 to 120 hours
Reported efficacy: 85 to 100% effective
Side effects: Less nausea and vomiting than the Yuzpe regimen. 18 % to 36 % of
women experienced delay of menses of more than three days. The side effects
were significantly related to the dose of RU 486 used. |
After 72 Hours
What is the patient presents for care after 72 hours have passed, and
the IUD is not an option? While we know that treatment efficacy does not
drop to zero 73 or 74 hours after exposure, there obviously is a cutoff,
somewhere around one week, beyond which an oral agent would be futile.
Prior to that point, the decision of whether or not to proceed becomes
a judgment call on the part of the patient and the physician. Although
intervention may not succeed, it might be worth a try if the patient wants
it, with the reassurance that no harm will be done is she becomes pregnant. |
