• A woman who vomits (for any reason) within 2 hours of taking a combined oral contraceptive (COC) should repeat the dose as soon as possible.
• If vomiting or severe diarrhoea persists for more than 24 hours, the instructions for missed pill should be followed (see Missed COC pills), counting each day of vomiting and/or severe diarrhoea as a missed pill:
• Additional contraceptive cover is required during the illness and for 7 days afterwards.
• If the illness occurs while taking the last 7 tablets, omit any pill-free period (or inactive tablets) and start the next cycle immediately.

In depth

• Identify and manage causes for bleeding irregularities such as missed pills, drug interactions, vomiting, severe diarrhoea.
• Exclude or manage other situations which could result in unscheduled bleeding, such as:
• Sexually transmitted infections.
• Risk of STI if the woman is under 25 years, or has a new sexual partner, or more than one partner in the last year.
• Pregnancy.
• Gynaecological conditions such as cervical cancer. Provided there is consistent and correct use of contraception, speculum examination is warranted:
• For persistent bleeding beyond the first 3 months of use.
• For new symptoms or a change in bleeding after at least 3 months of use.
• If the woman has not participated in a National Cervical Screening programme.
• If requested by the woman.
• After a failed trial of modification of COC treatment (at least 6–8 weeks).
• If there are other symptoms such as pain, dyspareunia, or post coital bleeding. (Note that these symptoms also warrant pelvic examination.)
• After potential causes have been excluded:
• Encourage persevering for up to three months for new users.
• Consider stopping the COC for up to 7 days and then restarting (and using an alternative method while protection is lost).
• Changing to a different COC (with a higher dose of oestrogen, or higher dose of progestogen or different type of progestogen).
• Changing to another form of contraception.

In depth

• Stop the combined oral contraceptive (COC) 4 weeks before any major surgery, surgery to the legs, or surgery with prolonged immobilization of a lower limb.
• If emergency surgery or immobilization (e.g. fractured leg) is necessary, the COC should be stopped and treatment to prevent thromboembolism should be given.
• Advise the use of another method of contraception that will minimize the risk for venous thromboembolism.
• No precautions are necessary for minor surgery where the duration of anaesthesia and immobilization is short (e.g. laparoscopic sterilization, varicose vein surgery, and tooth extraction).
• The COC should normally be recommenced at the first menses occurring at least 2 weeks after full mobilization.
• To restart the COC, take the COC on day 1 of the first menstrual period that occurs at least 2 weeks after full mobilization. If the woman has used a progestogen-only injectable in the interim, the COC can be restarted before the next injection would be due.

In depth