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Recommendations for Contraceptive Use |
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Combined Oral Contraceptives (COCs) |
Q.1. When is the best time to start
COCs?
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| a) COCs may be started any time
you can be reasonably sure that the woman is not pregnant, for
example, during the 7 days which begin with the onset of menses (days 1 through 7 of the
menstrual cycle). (See Q.2. for postpartum initiation and Q.3. for post-abortion
initiation.) |
a) Starting within the first 7
days lowers the possibility of beginning the pill while she is already pregnant (although
there is the possibility that the client is pregnant and implantation bleeding has been
mistaken for menses).
- Dixon GW, Schlesselman JJ, Ory HW,
Blye RP. Ethinyl estradiol and conjugated estrogens as postcoital contraceptives. Journal
of the American Medical Association 1980;244:1336-1339.
- Gray RH, Pardthaisong T, McDaniel EB,
Doyle P. The timing of the first injection of Depo Provera. IPPF Medical Bulletin
1975;9(3):3-4.
- Schiphorst LE, Collins WP, Roystar JP.
An estrogen test to determine the times of potential fertility in women. Fertility and
Sterility 1985;44:328-334.
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| b) For a woman having menstrual
cycles, no back-up method is needed if she is in the first 7 days of her menstrual cycle
and is still menstruating. If she is in the first 7 days of her cycle, but is not
menstruating, some programs may recommend use of a back-up method for 1 week. COCs may be started anytime you can be
reasonably sure the woman is not pregnant. However, if COCs are started after day 7 of
a regular cycle, the woman should also be counseled that:
- her regular bleeding pattern may be altered, and
- a back-up method (or abstinence) should be used for 7
days.
(For information concerning need for back-up method see COCs Q.7.) |
b) A back-up method is NOT
needed if the first package of pills is started while the woman is menstruating because
the risk of conception is virtually nil.
- After day 5 of the cycle, the risk of pregnancy begins to
rise.
- Smith SK, Kirkman RJE, Arce BB,
McNeilly AS, Loudon NB, Baird DT.
The effect of deliberate omission of Trinordiol®
or Microgynon® on the hypothalamo-pituitary-ovarian axis. Contraception
1986;34(5):513-522.
Some programs might recommend a back-up method for women
who are not menstruating at the time of COC initiation because there is a very slight risk
of conception from unprotected intercourse on day 7 of the cycle.
When back-up (or abstinence) is needed, it must be used
for 7 days because 7 days of exposure to COCs are required to suppress follicular
development.
- Molloy BG, Coulson KA, Lee JM, Watters
JK. "Missed pill" conception: fact or fiction? British Medical Journal
1985;290:1474-1475.
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| c) If the client is using the
28-day pill packet, she should start a new packet the day after she finishes the previous
packet (without a break). If the client is using the 21-day pill packet, she should skip 7
days before starting a new packet. If the pills are taken correctly, the client will
always begin a new packet on the same day of the week. |
c) The longer the pill-free
interval, the higher the risk of ovulation (e.g., a 10-day pill free interval confers a
10% risk of ovulation).
- Landgren BM, Emiczky CS. The effect on
follicular growth and luteal function of "missing the pill." Contraception
1991; 43(2):149-159.
- Killick SR, Bancroft K, Oelbaums MJ,
Elstein M. Extending the duration of the pill-free interval during combined oral
contraception. Advances in Contraception 1990;6:33-40.
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