Hormonal Contraception II- Chapter 15:

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Q 15. 1 What is an oral contraceptive?

An oral contraceptive (“The Pill”) is taken by mouth with the objective of preventing pregnancy. Currently oral contraceptives are taken by women only.

In 1921 it was suggested that extracts from ovaries could be used as oral contraceptives. Diosgenin was first extracted from the Mexican yam in 1941 and this continues to provide a source for the production of sex steroids including norethisterone (norethindrone in the USA) and progesterone (Progest – Q25.7; 28.16) and Crinone (Q25.7).

Q 15. 1 What is an oral contraceptive?
Q 15. 2 How popular are oral contraceptive pills?
Q 15. 3 What are the benefits of the combined oral contraceptive pill?
Q 15. 4 Will the pill improve my periods?
Q 15. 5 Could the pill change my libido (sex drive)?
Q 15. 6 What are the risks of taking combined oral contraceptive pills?
Q 15. 7 What side-effects could I have whilst taking the pill?
Q 15. 8 What is the effect of the combined oral contraceptive pill on body weight?
Q 15. 9 Will the pill increase my vaginal discharge?
Q 15. 10 Does the combined oral contraceptive pill increase the chance of pelvic infections?
Q 15. 11 What is the relationship between the pill and fibroids?
Q 15. 12 Could a combined oral contraceptive pill increase my blood pressure?
Q 15. 13 Do combined oral contraceptive pills have any effect on the blood?
Q 15. 14 What is the relationship between the combined oral contraceptive pill and thromboembolism?
Q 15. 15 What is the relationship between the combined oral contraceptive pill and heart attacks?
Q 15. 16 What is the relationship between the combined oral contraceptive pill and strokes?
Q 15. 17 Does the pill affect the breasts?
Q 15. 18 Could I feel depressed as a result of taking the pill?
Q 15. 19 What is the relationship between the combined oral contraceptive pill and cancer of the ovary?
Q 15. 20 What is the relationship between the combined oral contraceptive pill and cancer of the uterus?
Q 15. 21 What is the relationship between the combined oral contraceptive pill and cancer of the cervix?
Q 15. 22 What is the relationship between the combined oral contraceptive pill and cancer of the breast?
Q 15. 23 Where can I obtain further information about contraception?
Q 15. 24 Could I have some Web sites?
Women’s Health – Home Page

Q 15. 2 How popular are oral contraceptive pills?

An oral contraceptive was first used in a clinical trial in 1956. The pill became available in the USA in 1960 and in the UK in 1961. By 1986, 95% of sexually active women in the UK under the age of 30 had used the pill at some time and by 1991 almost half the women aged 20 years in the UK were taking it.

A survey in 1995 found that 25% of the 13 million women in the UK aged 16-49 were currently using the combined oral contraceptive pill. The peak age group was 20-24 with 48% of all women and 70% of contraceptive users choosing this method. The use of the various methods of contraception varies from country to country. In Japan less than 2% of women use the pill whereas in Holland 40% of sexually active women do so.

Q 15. 3 What are the benefits of the combined oral contraceptive pill?

The combined oral contraceptive pill suppresses the natural hormone cycle providing:

one of the most effective contraceptive methods available (Table 13.1).

less painful periods (Q15.4; 23.7).

less heavy periods (Q15.4; 24.17A).

improvement of premenstrual tension (Q25.8).

regular cycles for those with irregular periods.

The additional benefits include:

improvement of acne (Q5.10).

oestrogen for those with amenorrhoea (absent periods) and low oestrogen levels (Q6.21).

reduction of excess body hair (hirsutism – Q8.13).

reduced incidence of functional ovarian cysts (Q23.3).

improvement in endometriosis (Q23.21).

reduction in the incidence of cancer of the ovary and endometrium (Q15.19 and Q15.20).

The four-weekly bleeds that occur whilst taking the pill are not periods (menstruation) but withdrawal bleeds. Menstruation is a bleed that occurs each month spontaneously and not in women who are taking hormonal treatment such as the pill.

Q 15. 4 Will the pill improve my periods?

The majority of patients report reduced flow and less period pain. There are occasional exceptions so that a few ladies with light periods find their menstrual flow increased by the pill. During early pill cycles in particular there may be some breakthrough bleeding. Some women do not have a withdrawal bleed during the pill-free interval. If this happens for two consecutive cycles a pregnancy test should be considered. Absence of the withdrawal bleed is not detrimental to health. When the pill is discontinued, the periods may take a few months to return to normal. Premenstrual syndrome is less common whilst taking the pill although there may still be some symptoms for the last few days of the cycle.

Q 15. 5 Could the pill change my libido (sex drive)?

Relieved of the stress of possible unwanted pregnancy, some women report increased initiation of sexual activity. Others find their libido reduced, perhaps as there is some sub-conscious wish to have a child. If libido is reduced, vaginal discomfort due to infection should be excluded. Otherwise a change to a less progestogenic pill may help.

Q 15. 6 What are the risks of taking combined oral contraceptive pills?

The early combined oral contraceptive pills contained 150 mg of the oestrogen mestranol together with norethynodrel which is a progestogen. The first report of thromboembolism (a blood clot forming in a vein within the leg or pelvis and then travelling to the lungs) in association with the pill came soon after the combined oral contraceptive pills were introduced. The pharmaceutical industry has made enormous efforts to reduce the risks associated with the oral contraceptive pills whilst maintaining their contraceptive effectiveness. Essentially there have been two avenues that have been explored. Firstly, the amount of oestrogen in the pill has been reduced and secondly newer progestogens have been developed. The oestrogen in the combined oral contraceptive pill reduces LH and FSH production and therefore suppresses follicular development and ovulation (Q2.3). There has been concern that reducing the amount of oestrogen in the combined oral contraceptive pills could lead to contraceptive failure. Over the years it has been found that the lowest dose of oestrogen that remains effective is much lower than originally contemplated. The original 150 mg was reduced to 100mg then 50mg. The majority of pills prescribed today have less than 50mg of ethinyl oestradiol and two have just 20mg (Loestrin 20 – Parke Davis; Mercilon – Organon). At this level, the oestrogen content is only a little more than that found in hormone replacement therapy (HRT). HRT does not suppress follicular development or ovulation and it therefore follows that the 20mg oestrogen pills will be the minimum effective dose.

References:

Mortality among oral contraceptive users: 20 year follow up of women in a cohort study (1989-56)

Q 15. 7 What side-effects could I have whilst taking the pill?

The vast majority of patients taking the pill feel very well but, as with any medicine that has benefits, some minor side-effects are occasionally reported. These include:

• altered body weight (some gain a few pounds and others lose a little).

• nausea (feeling sick) and vomiting.

• mastalgia (breast tenderness).

• headaches (the pill should be stopped if they become severe).

• altered libido (sex drive – Q15.5) with many women noticing an increase and others a reduction.

• depression.

• reduced or absent menstrual flow (Q15.4; 24.17A).

These side-effects usually settle within two or three months.

Q 15. 8 What is the effect of the combined oral contraceptive pill on body weight?

All of us are intermittently gaining or losing weight. Inevitably some patients find that they gain weight around the time of starting the pill but others observe a weight loss. In a personal computer search of the medical literature from 1966 to date I found exactly fifty papers (articles in medical journals) where weight change in relation to the pill had been studied. Thirty-six papers indicated no change, eleven found an increase varying from 0.3kg to 2.4Kg. Three papers found weight loss with the pill for women who were overweight or who had polycystic ovaries.

References:

Twelve years of clinical experience with an oral contraceptive containing 30mug ethinyloestradiol and 150mug desogestrel (1995-2109a)

Effects of low-dose estrogen oral contraceptives on weight, body composition, and fat distribution in young women (1995-2109b)

Efficacy and safety of a monophasic and a triphasic oral contraceptive containing norgestimate (1994-2109c)

Clinical comparison of two low-dose oral contraceptives, Minulet(TM) and Mercilon(TM), in women over 30 years of age (1994-2109d)

Clinical experience with a modern low-dose oral contraceptive in almost 100,000 users (1991-2109e)

Clinical evaluation of a monophasic ethinylestradiol / desogestrel-containing oral contraceptive (1998-2109f)

A low-dose combination oral contraceptive. Experience with 1,700 women treated for 22,489 cycles (1981-2109g)

Q 15. 9 Will the pill increase my vaginal discharge?

Cervical ectopy (erosion – Q21.3) appears to be more common in women taking the pill although the newer lower dose pill seem to cause this less frequently. Cervical ectopy only requires treatment if there are persistent significant symptoms after excluding other problems such as infection. Contrary to popular belief, there is no evidence that the pill increases the incidence of candida (thrush).

Q 15. 10 Does the combined oral contraceptive pill increase the chance of pelvic infections?

There is no increase in the incidence of Candida infection in pill users. The incidence is the same as in women with intrauterine devices and those using no contraception. Bacterial infections that gain entry to the pelvis through the cervix are less common in pill users as the progestogen makes the cervical mucus thick. However, there is no protection against viruses or chlamydia.

Q 15. 11 What is the relationship between the pill and fibroids?

Surprisingly, studies show that the pill reduces the chance of fibroid development. It is a surprise because both oestrogen and progesterone are factors in fibroid development so fibroids shrink after the menopause (Q27.27). The current presumption is that the total of these hormones provided by the pill in a month must be less than the natural hormone output by the ovaries.

References:

Use of oral contraceptives and uterine fibroids: Results from a case-control study (1999-2753)

Q 15. 12 Could a combined oral contraceptive pill increase my blood pressure?

For the majority of women, the blood pressure increases on the pill by an average of 1mm Hg (a tiny amount). An increase of 5-10mm Hg may be of clinical importance but 1mm really does not matter. This is an example of a statistical (mathematical) proven increase that has no consequence from the medical point of view.

The international recommendation is that the pill should not be started or continued if your blood pressure is 160/100 or higher. High blood pressure can be a factor in heart disease and strokes and as a few women (about 1%) may develop clinically significant raised blood pressure, checks should be carried out periodically. Your blood pressure should be measured before you start the pill and three months later. If your blood pressure is normal it should be reviewed at six months intervals and after two years it can be reviewed annually.

Q 15. 13 Do combined oral contraceptive pills have any effect on the blood?

All chemicals in the blood are eventually removed and eliminated from the body. The liver plays a key role in this process and this is true for oestrogens and progestogens. The oestrogen and progestogens in the combined oral contraceptive pill results in a slight alteration in the “fat” chemistry of the blood. There is a rise in low-density cholesterol (Q27.4) and triglycerides and a reduction of high-density cholesterol. These changes have been reduced by the more modern pills. When we cut ourselves a blood clot forms to seal the wound and stop the bleeding. This involves a cascade of chemical reactions in the blood that lead to the clot forming. Some people are particularly prone to inappropriate blood clots, which occur within the veins usually in the legs or pelvis. If such a blood clots, which is called a deep venous thrombosis becomes dislodged they can travel to the lung and cause a pulmonary embolism, which is a serious life threatening condition. The combined oral contraceptive pills do have a slight adverse effect on the clotting mechanism. Again, the new low oestrogen dose preparations are less likely to lead to problems.

Q 15. 14 What is the relationship between the combined oral contraceptive pill and thromboembolism?

Deep venous thrombosis and pulmonary embolism are uncommon if you are young (Figure 15.1). There is a slight increased risk of these problems if you are taking a combined oral contraceptive pill and the risk is further increased for those who are overweight or who smoke. The newer and lower oestrogen dose pills probably cause fewer problems. To put the risk in context, a woman taking the pill is more likely to be hospitalised as a result of an accident than from a complication associated with her pill. A study by the World Health Organisation (WHO) published in 1995 provided evidence that the newer pills with their lower oestrogen content are associated with lower incidence of thromboembolism than the earlier higher oestrogen dose pills. This study also brought attention to the relationship between the progestogen in the pill and thromboembolism.

There have been three “generations” of progestogens used in oral contraceptives. The WHO study found that the second generation progestogen, levonorgestrel, was only half as likely to be associated with thromboembolism compared to the third generation progestogens desogestrel and gestodene. Essentially, the WHO study demonstrated that the second generation progestogens were associated with a lower incidence of thromboembolism than had been previously believed. The third generation progestogens were not found to be associated with higher risks than anticipated.

In October 1995, the Committee on Safety of Medicines issued an alert to doctors and the media recommending that women taking third generation combined oral contraceptive pills should change to second generation preparations. The presentation of the information was such that many women were inappropriately led to believe that the combined oral contraceptive pill was associated with high risk of mortality. There was a 10,000 increase in the number of pregnancy terminations in the next nine months. Some Hospitals reported a 25% increase in births in July and August of 1996. There are risks of mortality with pregnancy termination and with childbirth. The emotional trauma of pregnancy termination is not easily quantified.

Table 15.1 puts the risk of deaths from thromboembolism in perspective.

Table 15. 1 Deaths per million women.

‘Risk’

Deaths per million women

Second generation pill

‘approximately’ 2

Third generation pill

‘approximately’ 3

Pregnancy and childbirth

Road traffic accidents

Scuba diving

220

Smoker (aged 35)

1670

A change from a third generation pill to a second generation would be expected to prevent the death of one women in every million taking the pill. There are risks in most aspects of life. We cannot be complacent but every effort should be made to ensure that when clinical information is presented to the public, it is presented in perspective. One death in a million is a tiny risk but for any family (and doctor) involved it is a disaster of the most enormous proportion. There has been an indication that third generation progestogens may have been safer in relation to heart disease.

The latest evaluation of the third generation of the combined oral contraceptive pill has concluded that these pills can be prescribed as a first choice preparation. There are a number of factors to be taken into account when assessing risk and the tiny risks involved probably make it virtually impossible to distinguish risks between second and third generation pills.

References:

The public health implications of the 1995 ‘pill scare’. Review

Safety of modern oral contraception: the options for women: lessons to be learned.

[Review] (1999-3165b)

The role of selective prescribing in the increased risk of VTE associated with third-

generation oral contraceptives. [Review] (1999-3165c)

The aftermath of a pill scare: regression to reassurance. [Review] (1999 – 3165d)

Risk of venous thromboembolism in users of hormone replacement therapy (1996-1471)

Risk of hospital admission for idiopathic venous thromboembolism among users of

postmenopausal oestrogens (1996-1472)

Prospective study of exogenous hormones and risk of pulmonary embolism in women

(1996-1473)

Q 15. 15 What is the relationship between the combined oral contraceptive pill and heart attacks?

The combined oral contraceptive pill has slight adverse effects on the lipids (“fat” chemicals) in the blood and these changes are known risk factors for heart disease. Heart attacks before the menopause are rare. Studies of patients on the early high dose preparations of the pill found a five-fold increase in the incidence of heart attacks. Further studies demonstrated that there are usually confounding (additional) factors contributing to the attacks. In particular, smoking increases the risks. With the more modern low dose pills the risks are probably lower. The latest evidence suggests that there is no increased risk of heart attacks for oral contraceptive users. The current recommended advice is that smokers should discontinue the pill at the age of 35years. The best advice is that smokers should stop smoking.

References:

Oral contraceptives and myocardial infarction: Results of the MICA case-control study. (1999 – 2717)

Q 15. 16 What is the relationship between the combined oral contraceptive pill and strokes?

Strokes are uncommon in young women but there is a marginal statistical increase in those who have taken the pill. Strokes may involve haemorrhage (bleeding) within the brain or reduced blood supply (ischaemia) to part of the brain. In young women it is the bleed variety of stroke that is the more common. One study in Europe found no significant increase in the chance of the bleed variety of stroke in association with the pill. Smoking and high blood pressure are more important risk factors and these confuse any analysis of the risks of the pill.

Q 15. 17 Does the pill affect the breasts?

Many women find that their breasts are slightly larger when taking the pill. Breast discomfort (mastalgia) may respond to vitamin B 6 (pyridoxine) 50 mg once or twice daily. If this is ineffective gamolenic acid (Efamast – Searle) up to eight 40mg capsules or four 80mg capsules daily will usually be effective. Otherwise a change of pill should be considered. Should milk production occur (galactorrhoea) investigation of the prolactin hormone level is indicated (Q6.10). Benign breast disease (Q27.16) tends to improve when the pill is taken.

Q 15. 18 Could I feel depressed as a result of taking the pill?

A few women describe a little depression when taking the combined oral contraceptive pill. The pill does not cause severe depression. If a change of pill does not solve the problem, pyridoxine (Vitamin B6) 50mg daily may be beneficial but it can take up to two months to be effective.

Q 15. 19 What is the relationship between the combined oral contraceptive pill and cancer of the ovary?

Several studies have provided convincing evidence that ovarian cancer is less likely to occur in women who have taken the pill. Your risk of ovarian cancer is reduced by about 50% if you have taken the pill for at least five years. The protection continues for about 15 to 20 years after you stop taking the pill. This protection appears to be independent of the brand of pill used. It is likely that the pill needs to have been taken for a minimum of two years to achieve this protection. The incidence of ovarian cancer seems to be falling and this is likely to be related to this benefit of the pill.

Q 15. 20 What is the relationship between the combined oral contraceptive pill and cancer of the uterus?

Progesterone and progestogens protect against endometrial (lining of the womb) cancer. The combined oral contraceptive pill provides progestogen for 21 days each month. Studies indicate a 40% reduction in the incidence of endometrial cancer when the pill has been taken for more than five years. Protection continues for more than fifteen years after the pill is discontinued.

Q 15. 21 What is the relationship between the combined oral contraceptive pill and cancer of the cervix?

Sexual activity and number of partners are the factors that have large impacts on the incidence of pre-malignant and malignant conditions of the cervix (neck of the womb – Q32.16). Some early reports suggested that users of oral contraception were at increased risk. However, more recent investigations have found no difference between women using the pill, intrauterine contraceptive devices (coil) or depot injection. The sheath (condom) provides mechanical protection not only against pregnancy but also against sexually transmitted disease. It prevents transmission of the human papilloma virus believed to be responsible for cervical cancer. It may be that the early studies suggesting that the pill increased the risk were only reflecting the prevention of transmission of the virus with the barrier method.

There has been a suggestion that the pill may increase the chance of pre-malignant conditions of the cervix developing in women at risk but this remains an area of debate requiring more data. There is no reason to stop the pill if you have been found to have an abnormal smear test provided appropriate investigations and treatment are undertaken (Q21.5).

Q 15. 22 What is the relationship between the combined oral contraceptive pill and cancer of the breast?

This question is discussed in Q32.43.

Q 15. 23 Where can I obtain further information about contraception?

Some your useful sources of further information can be found at Q13.27.

Q 15. 24 Could I have some Web sites?

Evaluation of the quality of Web sites is discussed in Q4.27. You may find that several general women’s health sites may help you (Q4.28). The following are more specialised Web sites on topics found in this chapter:-

Q 15. 1 What is an oral contraceptive?

Q 15. 2 How popular are oral contraceptive pills?

Q 15. 3 What are the benefits of the combined oral contraceptive pill?

Q 15. 4 Will the pill improve my periods?

Q 15. 5 Could the pill change my libido (sex drive)?

Q 15. 6 What are the risks of taking combined oral contraceptive pills?

References:

Q 15. 7 What side-effects could I have whilst taking the pill?

Q 15. 8 What is the effect of the combined oral contraceptive pill on body weight?

References:

Q 15. 9 Will the pill increase my vaginal discharge?

Q 15. 10 Does the combined oral contraceptive pill increase the chance of pelvic infections?

Q 15. 11 What is the relationship between the pill and fibroids?

References:

Q 15. 12 Could a combined oral contraceptive pill increase my blood pressure?

Q 15. 13 Do combined oral contraceptive pills have any effect on the blood?

Q 15. 14 What is the relationship between the combined oral contraceptive pill and thromboembolism?

References:

Q 15. 15 What is the relationship between the combined oral contraceptive pill and heart attacks?

References:

Q 15. 16 What is the relationship between the combined oral contraceptive pill and strokes?

Q 15. 17 Does the pill affect the breasts?

Q 15. 18 Could I feel depressed as a result of taking the pill?

Q 15. 19 What is the relationship between the combined oral contraceptive pill and cancer of the ovary?

Q 15. 20 What is the relationship between the combined oral contraceptive pill and cancer of the uterus?

Q 15. 21 What is the relationship between the combined oral contraceptive pill and cancer of the cervix?

Q 15. 22 What is the relationship between the combined oral contraceptive pill and cancer of the breast?

Q 15. 23 Where can I obtain further information about contraception?

Q 15. 24 Could I have some Web sites?

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