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The Oral Contraceptive Pill

Gynaecology, Pregnancy, Fertility Dr Erin Nesbitt-Hawes Director
Recent media focus on the oral contraceptive pill has left many women with questions as to what the risks are, and should they be taking this medication.

The combined oral contraceptive pill (COCP) contains both oestrogen and progesterone and has been used for many years for a number of indications including birth control, pelvic pain, heavy menstrual bleeding and acne.  Recent media coverage of individuals who have suffered complications associated with COCP intake may have raised questions for many women about their own risks.

Common side effects of the COCP

While the COCP is used for many women as an answer to their bleeding problems, for some women the COCP can cause irregular bleeding and spotting. These symptoms are most common over the first 3 months of use and often settle down with time. Some women who skip their periods on the COCP (by taking the hormone tablets continuously instead of having the sugar pill break) also find that spotting may be an issue in subsequent months. The solution to this type of bleeding is to have a period by taking the sugar pills before resuming the hormone tablets.

Nausea can be a side effect of many medications and the same is true for the COCP. In addition the COCP can cause breast tenderness, mood disturbances, acne and skin pigmentation, changes of libido and bloating. Some of these side effects settle with time, and some will persist so it is always recommended you speak to your doctor if you are having medication side effects.

Although many women think that there is an association between the COCP and weight gain, numerous studies have failed to show this result. The unfortunate fact was that women tended to put on weight over time, whether they had been taking the COCP or not!

Risks of the COCP

The main risk of taking the COCP is associated with the oestrogen component (which is found in the combined OCP, not the progesterone only minipill) and can result in an increased risk of blood clotting. This may lead to deep venous thrombosis (DVT or blood clots in the legs) as well as the more serious pulmonary embolism (PE – where clots travel to the lungs) or stroke (clotting or bleeding in the brain).


It is well known that oestrogen increases the risk of clots (venous thromboembolism) including DVT and PE. In addition, there are increasing data to show that newer generation progestogens may also increase this risk. The numbers of women suffering these events are very small and the following  table puts things into perspective with the top section representing the risk of a venous thromboembolism and the bottom section comparing these risks with that of death in a motor vehicle accident (a risk that most of us are willing to accept on a daily basis).

OCP risks 2

Women who are taking the COCP should be aware of the signs and symptoms of DVT (swelling of usually one leg more than the other, pain in the calf region) and PE (sudden onset of shortness of breath and chest pain especially with a deep breath). If any of these symptoms occur, early consultation with your GP or emergency department is recommended.


Stroke is uncommon in women of childbearing age, estimated to be approximately 2/10,000 women each year. This risk doubles in women who are taking the COCP to 4/10,000 women per year. This is only slightly higher than the risk in pregnancy which is 3.4/10,000 women per year.

Some women have other risk factors for stroke or blood clots which means that their risk is increased overall. Examples include women with high blood pressure, clotting abnormalities, migraine with aura, obesity or smoking.

Avoiding the COCP

There are a few groups of women who should not take the COCP under any circumstance (described as an absolute contraindication):

  • Women who are breastfeeding and less than 6 weeks post-partum
  • A personal history of stroke, ischaemic heart disease, raised blood pressure (systolic >160, diastolic >100) or complicated valvular heart disease
  • Migraine with aura (where visual disturbance or flashes in front of the eyes is present)
  • Women >35 years of age who smoke >15 cigarettes per day
  • Type 2 diabetes with vascular complications
  • Past or current history of DVT/PE or a disorder which increases clotting
  • Major surgery with prolonged immobilisation
  • Current breast cancer
  • Body mass index (BMI >40)

In addition to those listed above, doctors are cautious prescribing the COCP to women who smoke, are over the age of 40, have a family history of clotting disorders, or in the first 6 months of having a baby if you are fully breastfeeding.

When it comes to stopping the OCP, it is recommended that you do this in consultation with your GP or gynaecologist.

Taking the COCP can have many benefits and these often outweigh the risks of clotting as described above. There are also alternative methods for contraception and symptom management available, so speak to your Alana gynaecologist about the options.