Oral Hormonal Contraceptives (the "Pill")
Dr. Nelson Soucasaux , Brazilian gynecologist
Initially I would like to say that, based on my 28 years of gynecologic
practice, the best of all available contraceptive methods continues to be
the "old Pill," that is, the oral hormonal contraceptives. And,
to my point of view, this observation about the oral contraceptives is valid
considering their positive benefit/risk relation and, obviously, the high
efficacy of the method. These products have been used for about 40 years
and constitute some of the most studied and researched medicines to date.
The fact is that, for most women, the contraceptive security, tranquility
and comfort provided by the oral hormonal contraceptives by far outweigh
the rare and occasional risks and problems that eventually may occur. We
must also consider that, during the last decades, the hormonal doses contained
in these medicines have been considerably reduced, and new synthetic hormones,
better tolerated and with fewer side effects, have also been developed and
utilized in the more recent products. In this way, the "Pill"
is constantly evolving and being improved.
Let us see, for instance, the reduction in the estrogen dose of the
oral contraceptives that took place in the last three decades. Up to 1974,
the usual dose of ethinyl estradiol contained in each tablet was 0.05mg
(considered excessive according to the desired safety standards, mostly
regarding the occurrence of some important, though fortunately rare, side
effects). However, in that same year it was already possible to successfully
reduce the daily ingestion of ethinyl estradiol to 0.03mg, preserving the
same efficacy with excellent tolerability and considerably fewer side effects.
Recently a new generation of oral contraceptives was developed, in which
the daily ingestion of ethinyl estradiol was once again successfully reduced
to 0.02mg (the low-dose "Pills"). Reductions in the progestogen
doses of these medicines have also been done. Therefore, as I have already
said, we can easily verify that the "Pill" actually has evolved
and has been considerably improved throughout the years.
And a few months ago, another product was released reducing once again
the aforementioned daily ethinyl estradiol dose to 0.015mg, together with
a reduction in the respective dose of the progestogen associated to it.
In order to counterbalance this considerable reduction without lessening
the contraceptive efficacy, this very new "Pill" is to be taken
in series of 24 days (instead of the usual 21 days) and the interval between
the series was reduced to 4 days (instead of the usual 7 days). Nevertheless,
I want to make it clear that this product is too new, the dosage is too
low and, personally, I still do not have all the necessary information regarding
its real contraceptive security. Though it seems to be effective if taken
in this new regimen of administration, I believe this new oral contraceptive
still demands more clinical studies.
All oral hormonal contraceptives consist of combinations of the already
mentioned synthetic estrogen ethinyl estradiol with one of the several existing
progestogens or progestins (synthetic "progesterones"). Of all
progestogens or progestins that have been utilized in these products, the
more important ones are the levonorgestrel, noretisterone, cyproterone,
desogestrel and gestodene. The newest generations of "Pills" contain
preferably the progestogens desogestrel and gestodene, since some of their
general metabolic effects seem to be smaller and more favourable than those
of the other progestogens. This implies an improved general metabolic profile.
The oral contraceptives that combine the estrogen ethinyl estradiol
with the progestogen cyproterone are specifically indicated for women with
hypertrichosis or slight hirsutism (excessive growth of hair on several
parts of the body) and acne, due to the well-known anti-androgenic effect
of cyproterone. This happens because cyproterone has the property of inhibiting
the androgenic action on almost all androgen-receptors of the body, among
them obviously the hair follicles. As a consequence, the hypertrichosis/hirsutism
and acne can be reduced under the effect of "Pills" containing
cyproterone. Nevertheless, this treatment must only be prescribed after
the completion of a careful investigation of these androgenic or hyperandrogenic
manifestations intended to correctly diagnose the real origin of this increased
growth of hair on several parts of the female body.
Almost all oral contraceptives used along the last decades are considered
"combined" and "monophasic." "Combined Pills"
are those in which all tablets in a series contain both estrogen and progestogen.
"Combined monophasic Pills" are those in which the respective
doses of estrogen and progestogen contained in all tablets along the series
are the same. Whenever the respective dose of estrogen or progestogen varies
along a series, implying the existence of two or three different kinds of
tablets in it, these "Pills" are said to be "biphasic"
or "triphasic" ones, and there are a few products of this kind
in the market. Nevertheless, as I have already said, almost all modern oral
contraceptives are "combined and monophasic," that is, the daily
hormonal ingestion is the same along the usual 21 days that constitute each
series of the "Pill."
Needless to remark that this hormonal composition varies according to
each specific kind of oral contraceptive available in the market - that
is to say, with each product. Therefore, there are and there have been lots
of different contraceptive pills, making use of different estrogenic-progestogenic
associations in many different respective doses. This great existing number
of different hormonal contraceptives, making use of different hormones in
varying doses, allows us to get close to "choosing the ideal 'Pill'
for each woman," individualizing the prescription as close as possible.
The "combined" oral hormonal contraceptives work by means
of three basic mechanisms:
1) they interrupt most of the ovarian function due to an interference
in the intricate feedback mechanisms of the hypothalamus-pituitary-ovaries
axis. The usual pattern of secretion of FSH (follicle stimulating hormone)
and LH (luteinizing hormone) by the pituitary is considerably altered.
As a result, the development of the ovarian follicles is interrupted at
their first stages of growth, and no one of them reaches the stage of a
mature follicle. The pituitary ovulatory peak of LH is also abolished.
This interference in the hypothalamus-pituitary-ovaries axis constitutes
the main mechanism of action of the hormonal contraceptives, resulting
on the suppression of ovulation;
2) they produce specific alterations in the endometrium (the mucosa
that covers the interior of the uterine cavity) which, in the case of an
eventual failure in the inhibition of ovulation, creates considerable difficulty
for the implantation of the fertilized egg;
3) they produce a thickening of the uterine cervix mucous secretion,
thus making it difficult for the ascension of the spermatozoa inside the
In this way, the "combined" oral contraceptives present a
main contraceptive mechanism (the interruption of the ovarian function and
the consequent inhibition of ovulation) and two other complementary mechanisms
(which, isolated, are not reliable but, associated with ovulatory suppression,
increase the final contraceptive efficacy).
As it is well known, the usual oral contraceptives are taken in series
of 21 days, with an interval of 7 days of rest between the series. In the
artificial cycles induced by the "Pill," this interval is intended
for imitating the usual hormonal fall that takes place at the end of each
natural cycle (which the female organism is physiologically used to) and
for allowing menstruation to come (though the menses that come after each
series of the "Pill" are artificial, since they are caused just
by this periodic interruption in the use of the hormonal contraceptive).
Considering that the hormonal contraceptives inhibit the ovarian function,
it is advisable that, at least once a year, women using the "Pill"
stay one or two cycles without taking it, in order to avoid a prolonged
inhibition of the aforementioned hypothalamus-pituitary-ovaries axis.
As to the present proposal of abolishing menstruation through the continuous
use of hormones, my opinion is clearly expressed in my article "Uninterrupted
use of hormonal contraceptives for menstrual suppression: why I do not recommend
it", published here at the MUM.
Before finishing, something else must be added about the oral hormonal
contraceptives. In the beginning of this article, I expressed my opinion
that they are the best and the safest of all contraceptive methods, because
the benefits provided by their use by far outweigh some risks and problems
that rarely may occur. But besides the great benefit of their high contraceptive
efficacy, other positive aspects related to the use of the "combined"
hormonal contraceptives have been demonstrated over the last years. They
consist basically on a reduction in the incidence of ovarian and endometrial
The minor incidence of ovarian cancer in women who have used the "Pill"
for a long time may be related precisely to the inhibition of ovulation.
Though the subject is still controversial, it is possible that very frequent
ovulations may be one of the many factors that predispose women to some
kinds of ovarian malignant neoplasias. As to the reduction in the occurrence
of endometrial cancer, the reason is that, during the use of the "combined
type" of hormonal contraceptives, women take an association of estrogen
and progestogen for three weeks each cycle. As a result, the progestogenic
component of these "Pills" taken for 21 days along each cycle
prevents the development of endometrial hyperplasias, a very common group
of pathologies that can be precursors of endometrial cancer.
Copyright Nelson Soucasaux 2002
Nelson Soucasaux is a gynecologist dedicated to clinical, preventive
and psychosomatic gynecology. Graduated in 1974 by Faculdade de Medicina
da Universidade Federal do Rio de Janeiro, Brazil, he is the author of several
articles published in medical journals, and of the books "Novas Perspectivas
em Ginecologia" ("New Perspectives in Gynecology") and "Os
Órgãos Sexuais Femininos: Forma, Função, Símbolo
e Arquétipo" ("The Female Sexual Organs: Shape, Function,
Symbol and Archetype"), published by Imago Editora, Rio de Janeiro,
Web site: www.nelsonginecologia.med.br