Combined oral contraceptives (COCs)
Combined oral contraceptives contain synthetic versions of naturally occurring estrogen
and progesterone. COC users may experience a variety of minor side effects
that are not likely to have important health implications but may result in dissatisfaction
with the method and early discontinuation. The estrogens in COCs increase
the risk of adverse cardiovascular events, but for women who do not smoke or have
other high-risk cardiovascular conditions, the increase is small.
Health benefits conferred by the use of oral contraceptives include decreases in:
• Irregular and painful menstrual cycles
• Blood loss during menstruation
• Premenstrual symptoms, premenstrual and mood disorders
• Ovarian cysts
• Ectopic pregnancy
• Acne and excessive body hair
• Noncancerous cysts or lumps in the breast
• Acute pelvic inflammatory disease
• Colorectal cancer and cancer of the ovary and endometrium
COC use increases the risk of venous blood clots called thrombotic and thromboembolic
events (VTE), including pulmonary embolism and deep vein thrombosis.
The background risk of venous thromboembolism (VTE) in women of childbearing
age is approximately 4 to 5/10,000 women over a year. VTE risk is increased by
two to three times by using COCs and possibly by as many as four times among
users of some types (third generation) of COCs to the range of 9 to 10/10,000 woman-
years of use.36 37 The risk of VTE is greatly increased among women who have
certain genetic mutation disorders that increase the risk of blood clots.38
Increased risk of an arterial thrombosis such as those causing strokes and heart
attacks is primarily among smokers or women with other underlying risk factors
for vascular disease such as hypertension, high cholesterol, morbid obesity, and diabetes.
There is no measurable increased risk of heart attacks among healthy young
women on the lowest dose COC formulations. Most studies have shown no increase
in the risk of stroke from the use of low-dose COCs among healthy users
who do not smoke or have high blood pressure. Other studies indicate a slight
increase in the risk of stroke in non-smokers and about a doubling of risk for stroke
among smokers. Women with severe high blood pressure are at risk of stroke, and
the use of COCs increases this risk additionally—they should avoid COCs and use
a different form of contraception.
Studies of lifetime risk of cancer among COC users are generally reassuring. The
Royal College of General Practitioners’ Oral Contraception Study found that ever
use of oral contraceptives was associated with reduced colorectal (incidence rate
ratio, 0.81), endometrial (incidence rate ratio, 0.66), ovarian (incidence rate ratio,
0.67), and lymphatic and hematopoietic cancer (incidence rate ratio, 0.74).39 An
increased risk of lung cancer was seen only among ever users who smoked at recruitment.
An increased risk of breast cancer (incidence rate ratio, 1.48) and cervical
cancer (incidence rate ratio, 2.32) that was seen in current and recent users
appeared to be lost within approximately five years of stopping oral contraception,
and long-term hormonal contraceptive use has been found not to be associated with
any increase in total cancer risk.
Numerous studies show that the use of hormonal contraceptives is associated with
a significantly lower overall risk of death than occurs among non-users.41 Studies
suggest that the net effect of the use of oral contraceptives for five years or longer
is a slight reduction in the total risk of cancer. The authors of a Royal College
study concluded, “the overall balance of cancer risk among past users of oral contraceptives
was neutral with the increased risks counterbalanced by the endometrial,
ovarian, and colorectal cancer benefits that persist at least 30 years.”
The short-term increase in the risk of dying from the use of COCs, mostly from
cardiovascular disease, can be compared to the risk of death from pregnancy and
childbirth. In the U.S., about one of every 10,000 births is fatal to the woman giving
birth.44 For healthy women aged 15 to 34 who do not smoke, the risk of death over
a year of oral contraceptive use is one out of 1,667,000 (.006/10,000). For smokers
aged 15 to 34, the risk of death increases to one out of 33,330 (0.3/10,000). For
women aged 35 to 44, the risk of death over a year is one out of 57,803 (0.2/10,000),
and for smokers ages 35 to 44, the risk of death increases to one out of 5,155
(1.9/10,000). This data shows why COC use is relatively safe, except for women
over age 35 who smoke. They should consider the use of a contraceptive other than
Contraceptive patch and vaginal contraceptive ring
Because the transdermal contraceptive patch and vaginal contraceptive ring release
an estrogen and a progestin, the risk and benefit profile is similar to that of COCs.
About half of users will experience skin reactions at the patch site. Side effects
among ring users include vaginal symptoms and very rarely, toxic shock syndrome.
The advantages of the patch and ring are considered to be similar to those afforded
by COCs. However, the one-patch-per-week dosing schedule for the patch and a 21
days-in-place or a longer schedule for some rings may be easier to adhere to than a
This blog presents opinions and ideas and is intended to provide helpful general information. I am not engaged in rendering advice or services to the individual reader. The ideas, procedures and suggestions in that are presented are not in any way a substitute for the advice and care of the reader’s own physician or other medical professional based on the reader’s own individual conditions, symptoms or concerns. If the reader needs personal medical, health, dietary, exercise or other assistance or advice the reader should consult a physician and/or other qualified health professionals. The author specifically disclaims all responsibility for any injury, damage or loss that the reader may incur as a direct or indirect consequence of following any directions or suggestions given in this blog or participating in any programs described in this blog or in the book, The Building Blocks of Health––How to Optimize Your Health with a Lifestyle Checklist (available in print or downloaded at Amazon, Apple, Barnes and Noble and elsewhere). Copyright 2021 by J. Joseph Speidel.