THE BIRTH CONTROL PILL: HOW DOES IT WORK? IS IT SAFE?
Controversy has surrounded "the Pill" ever since it was first marketed in
the United States in 1960. It has been studied medically, sociologically
and morally, and yet much confusion still exists concerning these potent
artificial steroids. The billions of dollars at stake in the marketing of
the Pill and the power of the birth control industry to lobby both
lawmakers and the media can easily divert the average person from the
truth. Research has been published, books have been written, and common
sense should make one cautious.
The following information is presented to raise awareness about the Pill.
Footnotes are marked with astrisks; all footnotes appear at the end of
this document in a section titled REFERENCES.
WHAT IS THE BIRTH CONTROL PILL?
The Birth Control Pill is any drug which uses artificial hormones to keep
a woman from getting pregnant or from staying pregnant by interfering with
her normal fertility. Are all forms of the Pill the same?
No. There are several types of the Pill on the market, but they basically
break down into two groups: combination pills and the progestin-only
"minipill."
The combination type contain two artificial steroids that mimic the
effects of naturally occurring hormones, estrogen and progesterone. Some
pills work in a "monophasic" way, keeping the dosage of hormones the same
throughout the pill cycle. Others work in a biphasic or triphasic manner
which alters the dosage of artificial hormones two or three times
respectively through the cycle of pills, attempting to produce
fluctuations similar to what a fertile woman would undergo naturally.
The progestin-only "minipill" uses only one artificial hormone, progestin,
which is a steroid that has a progestational effect similar to natural
progesterone.
HOW DOES THE PILL WORK?
The Pill is designed to interfere with several normal functions of
fertility in order to make a woman 1) unable to conceive due to temporary
sterility or sperm immobility, and/or 2) unable to carry a pregnancy to
term(an early abortion). This process can be accomplished in various ways.
1. Suppressing Ovulation: When a woman ovulates, hormones released from
the pituitary , a gland located at the base of the brain, stimulate her
ovaries to ripen and release an egg. The combination pill usually
interrupts the release of these pituitary hormones resulting in no egg
being released from the ovary, thus preventing pregnancy from occurring.
With no egg available for fertilization, the woman is chemically sterile.
The progestin-only pill, however, has a weaker effect. It generally does
not suppress ovulation.[1]
2. Inhibiting Implantation: Another important aspect of fertility is the
process by which the lining of the uterus is replenished and maintained.
After an egg is fertilized, it normally implants in this lining
(endometrium), drawing nourishment and sustenance. The progestin
component of the combination pill and the progestin-only minipill cause
the inner lining of the uterus to become thin and shriveled, unable to
support implantation of the embryo(newly fertilized egg).[2]
3. Impeding Sperm Migration: Preceding ovulation, a woman's cervix
produces a watery mucus through which sperm swim to meet the egg. The
mucus also provides nourishment to sustain the life of the sperm cells.
This mucus thickens under the influence of a progestin and so impedes
sperm migration.[3]
There are two other factors in a woman's fertility that may be affected by
the Pill.
4. Making changes in the Fallopian Tubes: Progestins lower the efficiency
with which the fallopian tubes propel eggs from the ovaries toward the
uterus. This can cause the embryo not to reach the uterus in time to
implant successfully.[4]
5. Stopping a Pregnancy: After an ovary releases an egg, the woman's cycle
is controlled by a gland that is formed from the now-empty egg sack, the
corpus luteum; this normally functions long enough to give an embryo time
to implant in the uterus and for the placenta to begin to support the
pregnancy.
However, hormones from the Pill can cause the corpus luteum to function
inadequately, allowing the lining of the uterus to be shed before the
embryo can successfully implant.[5]
In summary, a woman's natural fertility requires several systems and
organs to coordinate smoothly. The synthetic chemicals in any type of
birth control Pill interfere with this coordination, adversely affecting
her normal fertility and any "accidental" conceptions.
HOW EFFECTIVE IS THE PILL?
In theory, the Pill reaches an effectiveness of over 99%, but in practice
the rate is much lower. Between 1.9% and 18.1% of women will experience an
unplanned pregnancy in the first year of using the Pill.[6]
Surprise pregnancies with the Pill are due to a number of factors.
Interactions between the Pill and some other medications interfere with
the proper blood levels of hormones necessary for their birth control
effect. These drug interactions may be significant with the commonly used
"low dose" Pill where slight alterations in hormonal blood levels can
result in more frequent ovulations and hence unplanned pregnancies.
Another factor in Pill pregnancy rates is not following directions,
sometimes due to the lack of motivation, especially in younger women (ages
15-24).
IS OVULATION ALWAYS SUPPRESSED?
No. Ovulation occurs in 2% to 10% of cycles of women taking the
Pill.[7][8][9][10][11][12][13] If 60 million women worldwide are on the low-dose
Pill, there would be 1.2 to 6 million ovulations per cycle. This is known
as breakthrough ovulation, and it is even more frequent with the
progestin-only Pill.[14][15]
WHAT HAPPENS WHEN OVULATION DOES OCCUR?
When the Pill fails to prevent ovulation, the other mechanisms come into
play. Thickened cervical mucus may make it more difficult for the sperm
to reach the egg; however, if the egg is fertilized, a new life is
created. The hormones slow the transfer of the new life through the
fallopian tube, and the embryo may become too old to be viable when it
does enter the uterus. If the embryo is still viable when it reaches the
uterus, under-development of the uterine lining caused by the Pill
prevents implantation. The embryo dies and the remains are passed along in
the next bleeding episode which, incidentally, is not a true menstruation
even though it is usually perceived as such.
DOES THIS MEAN THE PILL CAN CAUSE AN EARLY ABORTION?
Yes. Preventing the newly conceived life in its embryonic stage from being
transported to the uterus and preventing implantation in the wall of the
uterus are the "abortifacient" properties of the Pill.
WHY HAVEN'T I HEARD ABOUT THIS BEFORE?
The Pill manufacturers and many in organized medicine are mainly concerned
about the Pill's medical side effects and its effectiveness in preventing
pregnancies and are less concerned about how the drug achieves its
effectiveness.
Unfortunately, many "otherwise" pro-life physicians and pharmacists find
it hard to admit that these abortifacient properties exist because they
would have to discontinue prescribing and dispensing the Pill if they were
to remain consistent in their respect for life at all its stages of
development.
Pro-abortion organizations and their lawyers readily admit the early
abortion potential of the Pill. In February 1992, writing in opposition to
a Louisiana law banning abortion, Ruth Colker, a Tulane Law School
professor, wrote, "Because nearly all birth control devices, except the
diaphragm and condom, operate between the time of conception...and
implantation.., the statute would appear to ban most contraceptives."[16] In
1989, attorney Frank Sussman argued before the U. S. Supreme Court that ".
. IUDs (and) low dose birth control pills. . . act as abortifacients."[17]
WHAT ARE THE COMMON SIDE EFFECTS OF THE PILL?
There is a range of risks from serious or fatal to minor and trivial. The
following is a list of the most common side effects experienced by women
taking the Pill. These effects are dose related and not every woman will
experience them, but the risks still exist.[18][19] The synthetic estrogens
of the combination Pill cause many of these; the progestin causes others
and is the only risk factor in the progestin-only Pill (and the
progestin-only implant, Norplant).
HEART AND BLOOD ABNORMALITIES
Blood Clots can form, restricting or blocking the flow of blood to
critical organs and other body systems, possibly causing permanent damage.
For example, a blood clot in the heart would cause a heart attack; in the
brain it would cause a stroke or brain hemorrhage; a clot which moved from
elsewhere in the body and lodged in the lung would cause a pulmonary
embolism; in the kidneys a clot would cause a renal artery thrombosis and
kidney damage; in the retinal arteries it would cause temporary or
permanent blindness.
Studies continue to indicate approximately a 2-fold increased risk of
fatal heart attacks among users of the current low-dose pill when compared
to non-users.[20] This risk is lower than the risk experienced with the
older high dosage pill, but it continues to be significant. Similarly, the
risk of a fatal brain hemorrhage is increased 1.4 times when comparing
users to non-users. Among women who smoke, there is a 12-fold increase in
fatal heart attacks and a 3.1-fold increase in fatal brain hemorrhage.[21]
High Blood Pressure and alterations in the blood clotting mechanisms may
be seen in women on the Pill.[22] This may contribute to a 3-11 times
increased risk of developing blood clots in Pill users compared to
non-users. The risk is especially great for women who smoke and/or are
over 35 years old.[23]
CANCER
Breast cancer has been repeatedly associated with using the
Pill.[24][25][26][27][28][29][30][31]
Breast cancer has been increasing at an alarming rate in recent years,
especially among young women. "Breast cancer will kill more than 44,000
American women this year alone," a 1991 report noted,[32] predicting 175,000
more new cases, "especially among young women."
Why is there such an increase of breast cancer among younger women? Note
first that women rarely develop breast cancer shortly after they start
taking artificial hormones. It is generally not until ten or more years
after usage was initiated that women develop breast cancer. Then note that
in the United States, since the mid-1970s, it has been common for the Pill
to be prescribed for girls in their teen years. Common sense connects the
link between giving the Pill to young girls in the 1970s and the later
increase in breast cancer 15 to 20 years later among women in their late
twenties and thirties. This conclusion was demonstrated in a study which
found that Swedish women who took the Pill in the 1960s incurred a five
times greater increase in breast cancer when compared to non-users.[33]
The increased risk of breast cancer is seen in younger, nulliparous women
(never having borne children), and in long duration groups (greater than
five years) of Pill users. Large tumors and a worse survival rate are
associated with the Pill's use at an early age.
Will the newer formulated low-dose pills decrease the incidence of breast
cancer? A consensus of understanding has not been reached, and another 10
to 20 years of experience with women using this form of the Pill must be
gained before more definite conclusions can be reached.
Breast tenderness, enlargement, lumps, and milk secretions also may occur
in women using the Pill. Doctors are warned not to prescribe the Pill to
women who are "known or suspected" to have breast cancer.[34] It is
difficult to say what aggravating effect the Pill's hormones would have
over a truly random sample of women taking the Pill.
Cervical Cancer and cervical dysplasia increase among women who use the
Pill.[35][36][37][38][39] How long the Pill has been taken, how many sexual
partners a woman has had, at what age she began having intercourse,
whether she smokes, the hygiene of sexual partners and the transmission of
the human papillomavirus(HPV) are also factors in cervical abnormalities.
Because of these several factors, the connection of the Pill and cervical
cancer may be clouded over. However, there is no doubt that the promotion
of the Pill has resulted in early intercourse which may be the more direct
cause of cervical cancer.
Endometrial and Ovarian Cancer appear to have a lower incidence in both
women on the Pill and in those who have been previous users of the Pill.
Much of this data comes from studies of women who were using the higher
dose estrogen/progestin Pill. Currently the low dose monophasic and
triphasic pills (less than 50mcg of estrogen) are the only birth control
pills available on the U.S. market. It is not known if a similar
protective effect will be experienced with the currently used Pill. More
time is needed to study this issue, and the slight protective effect is
hardly a reason to take the Pill at the risk of so many other side
effects.
It should also be noted that these forms of cancer are rare and primarily
occur among postmenopausal women in their fifties and sixties. Second,
these cancers tend to occur in those women who had long cycles (i.e., with
a prolonged estrogen-dominant phase) or those who have a family history of
these types of cancer. Third, extended breastfeeding amenorrhea offers the
same type of protection against these cancers since the menstrual cycle
would be suppressed and therefore the exposure to estrogen suppressed.
Liver Tumors in younger women (15 to 40 years) have increased as the use
of oral contraceptives has increased. Almost unheard of in this age group
before the use of synthetic hormones became commonplace, liver tumors
usually do not occur until the sixth decade of a woman's life.
A study by the American College of Surgeons' Commission on Cancer found "a
large peak in the 26-to-30-year age group which corresponds with the
increased use of oral contraceptives in this age group."[40] Liver cancer in
women on the Pill is typically associated with those over 30 who have used
it more than four years, but cases of liver cancer in younger women have
been cited.[41][42][43][44]
Other Cancers: Skin cancer (melanoma) has also been found to increase
among women on the Pill. Naturally occurring estrogen is involved with
maintaining healthy skin tissue. It is reasonable to suspect that exposure
to the more potent synthetic estrogen in the Pill increases the risk of
this type of cancer.[45][46][47]
CYCLE IRREGULARITIES
Women who take the Pill have been reported to experience bleeding or
spotting in mid- cycle, changes in menstrual flow, and even loss of
menstruation, which can lead them to wonder if they are pregnant. For
some, painful menstruation (dysmenorrhea) has been reported to worsen,
even though many women take these hormones in an attempt to relieve the
problem.[48]
Although some women are given the Pill for irregular cycles, it does
nothing to improve the underlying problem causing the irregularity. Often
the irregularity returns when the Pill is discontinued, sometimes more
severely.
ARE THERE OTHER SIDE EFFECTS?
Yes. Some side effects are minor while some may be more severe and call
for discontinuing the drug.[49][50][51]
The following adverse effects have been experienced by women on the Pill:
Headaches, migraines, mental depression (even to the point of suicide
and/or suicidal tendencies), a decrease or loss of sexual drive, abdominal
cramps, bloating, weight gain or loss, and water retention; nausea and
vomiting(in about 10% of users); symptoms of PMS, vaginitis and vaginal
infections, changes in vision (temporary or permanent blindness, and an
intolerance to contact lenses); gall bladder disease and either temporary
or permanent infertility, when discontinuing the Pill, in users with
previous menstrual irregularities or who began the drug before full
maturity. Several of the symptoms, such as migraine headaches,
contraindicate the use of the Pill because of life endangering
complications.
Consult the Physicians' Desk Reference at your public library or consult
your pharmacist for a more complete list of the Pill's harmful effects.
IS THE PILL SAFER THAN PREGNANCY?
No. The health risks of the Pill outweigh by far the risks of pregnancy
and childbirth to a woman's health,[52] and any claim to the contrary is
based on erroneous comparisons between healthy women on the Pill and women
who do not receive normal care during pregnancy.
A precondition for obtaining the Pill is routine medical care and
checkups. For example: if such a woman on the Pill is diagnosed as
"precancerous," or if some other side effect is exhibited, she has the
advantage of early detection. However, many pregnant women do not receive
routine medical care. A clearer picture of the safety of the Pill compared
to the safety of pregnancy would be made if healthy women receiving
routine medical care during pregnancy and delivery were compared with
women receiving routine medical care while taking the Pill.
The mortality statistics of childbirth have continuously declined since
the early part of this century, mostly due to better maternal
healthcare.[53] Most of the high risk pregnancies and deliveries occur to
women who have not sought proper medical attention.[54] This is most evident
in the Third World where adequate health care is sparse.
Mortality statistics of pregnancy and delivery, usually called maternal
mortality, include the mortality rates due to abortion. Abortion is
clearly used as birth control, preventing the birth of the child;
therefore it must be included with the mortality statistics of birth
control methods. In one study, 25% to 50% of the reported maternal
mortality was a result of deaths from abortion.[55]
Fifty percent of woman taking the Pill discontinue it within the first
year because of side effects, the development of benign breast disease, or
some abnormality of the sexual organs. Studies of Pill usage do not
include these women, and the result is an unbalanced picture of only the
healthiest of women who tolerate the Pill.[56] This is compared with the
general population of women who are pregnant.
The fact is that there are 13.8 million women in the U.S. and 60 million
women worldwide who use the Pill (conservative numbers).[57] And there are
7.9 Pill-related deaths per 100,000 women ages 15-44.[58]
Therefore, one can calculate that there are over 1090 deaths each year in
the U.S. alone simply due to the Pill.
But I've heard there are no side effects with the Pill I use.
All drugs, including all brands of the birth control pill, have potential
side effects. There is no telling in advance how any particular woman will
react to the Pill, but there is a good chance of some type of reaction. It
is possible that a woman will be unaware that there is any connection
between the reaction and the Pill especially if it takes years to manifest
itself.
AREN'T THERE ANY THERAPEUTIC BENEFITS FROM THE PILL?
The only "indication," or use for the Pill that is approved by the Food
and Drug Administration is "the prevention of pregnancy in women . . . as
a method of contraception."[59] Some unapproved uses, considered
experimental, include its use as a "morning after" pill (causing an early
abortion), and for relief from the symptoms of mild endometriosis.[60]
I'M BREASTFEEDING MY BABY; CAN I USE THE PILL?
No. Artificial hormones pass from breast milk to the baby; the Pill also
decreases both the quantity and protein content of the milk produced.[61]
WHAT IS MY ALTERNATIVE TO USING THE PILL?
Natural Family Planning (NFP) is safe, healthy and effective and it's also
inexpensive. A woman observes and records changes in her basal body
temperature, the normal flow of cervical mucus, and if she wishes, the
physical changes in the cervix itself. She then crosschecks these signs of
fertility to follow, day by day, the natural course of her fertility
cycle. No drugs, no devices, no surgical procedures, no threat of death,
no side effects, no chemical abortions!
DOES NFP REALLY WORK?
Yes. Married couples can achieve a 99% effectiveness if they learn the
method, correctly interpret the fertility signs, and follow the rules.[62]
One positive side benefit for couples who are committed to making this
method work is the potential for a healthier marriage -- psychologically,
physically and spiritually.[63][64]
-- Paul Weckenbrock, R.Ph.
How can I find out more about Natural Family Planning?
Write the national office of The Couple to Couple League, P. O. Box
111184, Cincinnati, OH 45211; (513) 661-7612.
ENDNOTES
1. Hatcher RA, Guest F, Stewart F, 4 others (1988). Hormonal Overview.
Contraceptive Technology (14th ed) New York:Irvington Publishers 191-192.
The basic information is also contained in the package insert. See
reference 14.
2. Mishell D (Dec 1976). Current status of oral contraceptive steroids.
Clin Ob Gyn 19 (4) 746-747.
3. Diczfalusy E (Jan 1968). Mode of action of contraceptive drugs. Am J Ob
Gyn 100 (1) 156-157.
4. Bronson RA (Sept 1981). Oral contraception: mechanism of action. Clin
Ob Gyn 24 (3) 873-874.
5. Hatcher RA (1988) 192.
6. Harlap S, Kost K, Forrest JD (1991). Preventing Pregnancy, Protecting
Health. New York: The Alan Guttmacher Institute, 36-37.
7. Ehmann R (Sept 1990). Problems in family planning. Report delivered at
the International Congress of the World Federation of Doctors Who Respect
Human Life. Dresden, Germany.
8. Hatcher RA (1988). 191-192.
9. Killick S, Eyong E, Elstein M (Sept 1987). Ovarian follicular
development in oral contraceptive cycles. Fertil Steril 48 (3), 409-413.
10. Edgren RA, Sturtevant FM (Aug 1976). Potencies of oral contraceptives.
Am J Ob Gyn 125 (8), 1030.
11. We are close to lowest steroid dosage in the Pill (Nov 26-30 1984).
News and Views. Excerpts from the second annual meeting of the Society for
the Advancement of Contraception, Jakarta; edit Korteling W. Organon
International. West Orange, NJ (U.S.).
12. Van der Vange N (1988). Ovarian activity during low dose oral
contraceptives. Contemporary Obstetrics and Gynecology. Edit Chamberlin
G. London: Butterworths, 315-326.
13. Peel J, Potts M (1969). Textbook of Contraceptive Practice. Cambridge:
Cambridge University Press, 99.
14. Ovrette (1993) Physicians' Desk Reference. Montvale, NJ: Medical
Economics Co, 2606.
15. Bronson RA (Sept 1981). 869.
16. Colker R (Feb 6 1992). Louisiana abortion is a very real threat to
women. The Dallas Morning News, 23A.
17. Argument by Frank Sussman, Lawyer for Missouri Abortion Clinics (Apr
27 1989). New York Times, National Edition, 15.
18. Oral Contraceptives (Nov 1989 insert). Edit Olin BR. Facts and
Comparisons. St. Louis: Walters Kluwer Co., 107c-108
20. Thorogood M, Mann J, Murphy M, Vessey M (1991). Is oral contraceptive
use still associated with an increased risk of fatal myocardial
infarction? Report of a case- control study. Br J Ob Gyn 98, 1245-1253.
21. Thorogood M, Vessey M (1990). An epidemiologic survey of
cardiovascular disease in women taking oral contraceptives. Am J Obstet
Gynecol 163 (1) pt 2, 274-281.
22. Stampfer MJ, Willett WC, Colditz GA, Speizer FE, Hennekens CH (1990).
Past use of oral contraceptives and cardiovascular disease: A
meta-analysis in the context of the Nurses' Health Study. Am J Obstet
Gynecol 163 (1) pt 1, 285-291.
24. Olsson H, Ranstam J, Baldetorp B and 4 others (1991). Proliferation
and DNA ploidy in malignant breast tumors in relation to early oral
contraceptive use and early abortions. Cancer 67 (5), 1285-1290.
25. U.K. National Case-Control Study Group (1989). Oral contraceptive use
and breast cancer in young women. Lancet 1 (8645), 973-982.
26. Meirik O, Lund E, Adami H and 3 others (1986). Oral contraceptive use
and breast cancer in young women. Lancet 2 (8508), 650-653.
27. Rushton L, Jones D (1992). Oral contraceptive use and breast cancer
risk: a meta- analysis of variations with age at diagnosis, parity and
total duration of oral contraceptive use. Br J Obstet Gynecol 99, 239-246.
28. Miller DR, Rosenberg L, Kaufman DW and 3 others (1989). Breast cancer
before age 45 and oral contraceptive use: New Findings. Am J Epidemiol 129
(2), 269-280.
29. Pike MC, Henderson BF, Krailo MD. Duke A, Roy S (1983). Breast cancer
in young women and use of oral contraceptives. Possible modifying effect
of formulation and age at use. Lancet 2 (8356), 926-930.
30. Stadel BV, Lai S, Schlesselman JJ, Murray P (1988). Oral
contraceptives and premenopausal breast cancer in nulliparous women.
Contraception 38 (3), 287-299.
31. Kay CR, Hannaford PC (1988). Breast cancer and the Pill - A further
report from the Royal College of General Practitioners' oral contraception
study. Br J Cancer 58, 675- 680.
32. Rather D, Jones P, Moriarity E, Corderi V, Taira L (May 1 1991).
Beating breast cancer. New York: CBS.
33. Olsson H, Borg A, Ferno M, Moller TR, Ranstam J (1991). Early oral
contraceptive use and premenopausal breast cancer - A review of studies
performed in Southern Sweden. Cancer Detect Prev 15 (4), 265-271.
34. Oral Contraceptives (Nov 1989 insert). Facts and Comparisons. 107c.
35. Oral Contraceptives in the 1980s (May-June 1982). Population Reports.
Baltimore: Johns Hopkins University, Series A(6), A-203.
36. Hume K (1985). The pill and cancer. Linacre Quarterly 52 (4), 306-311.
37. Roy S, Bernstein L, Stanczyk FZ (1988). Analysis of oral contraceptive
risks. Female contraception eds: Runnebaum B, Rabe T, Kiesel L.
Berlin-Heidelberg: Springer-Verlag 29-30.
38. Hatcher RA, Stewart F, Trussell J and 4 others (1990). The pill:
Combined oral contraceptives. Contraceptive Tecnhology New York: Irvington
Publishers, 243-244.
39. Schlesselman JJ (1989). Cancer of the breast and reproductive tract in
relation to use of oral contraceptives. Contraception 40 (1), 20-25.
40. Hume K (1985). 305-306.
41. Roy S (1988). 30-31.
42. Oral contraceptives in the 1980s (May-June 1982). Population Reports.
A-204.
43. Oral contraceptives (November 1989 insert). Facts and Comparisons.
107e.
44. LaVecchia C, Franceschi S, Bruzzi P, Parazzini F, Boyle P (1990). The
relationship between oral contraception use, cancer and vascular disease.
Drug Safety 5 (6), 436- 446.
45. Hatcher RA (1990). 244.
46. Holly EA, Weiss NS, Liff JM (1983). Cutaneous melanoma in relation to
exogenous hormones and reproductive factors. J Natl Cancer Inst 70, 827.
47. Beral V,Evans S,Shaw H,Milton,G (1984). Oral contraceptive use and
malignant melanoma in Australia. Br J Cancer 50, 681-685.
48. Oral Contraceptives (Nov 1989 insert). Facts and Comparisons. 108.
49. Murad F, Haynes RC (1985). Estrogens and progestins. The
Pharmacological Basis of Therapeutics, eds:Gilman AG, Goodman LS, Rall TW,
Murad F. New York: Macmillan, 1435-1436.
50. Ehmann R (1990). 10-15.
51. Hatcher RA (1990). 237-240.
52. Beral V (1979). Reproductive mortality. Br Med J 2, 632-634.
53. Sachs BP, Layde PM, Rubin GL, Rochat RW (1982). Reproductive mortality
in the United States. JAMA 247 (20), 2789-2792.
54. Hatcher RA (1990). 528.
55. Schuitemaker NWE, Gravenhorst JB, Van Geijn HP, Dekker GA, Van Dongen
PWJ (1991). Maternal mortality and its prevention. Eur J Obstet Gynecol
Reprod Biol 42, 531-535.
56. Grant E (1985). The bitter pill. London: Elm Tree Books, 103.
60. Oral Contraceptives (Nov 1989 insert). Facts and Comparisons. 107c.
61. Oral Contraceptives (Nov 1989 insert). Facts and Comparisons. 107g.
62. Wade ME, McCarthy P, Braunstein GD and 5 others (1981). A randomized
prospective study of the use-effectiveness of two methods of natural
family planning. Am J Obstet Gynecol 141 (4) 368-376.
63. Kippley, J Kippley, S (1991). The Art of Natural Family Planning. (3rd
ed, 5th print) Cincinnati: Couple to Couple League 59-74.
64. Tortorici, J (1979). Conception regulation, self-esteem, marital
satisfaction among Catholic couples: Michigan State University study. Int
Rev NFP III(3) 191-205.
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c 1993 The Couple to Couple League International, Inc. P.O. Box 111184,
Cincinnati, OH 45211-1184, USA. (513) 661-7612
This information is from a brochure titled "The Pill: How does it Work? Is
it Safe?" The brochure and related material may be ordered from Couple to
Couple League direct or through CRNET's Catholic MarketPlace.
