Sexplanations with Stacey: The grapefruit is the culprit

Stacey Jacobs
Stacey Jacobs is the Community Sexual Health Educator at Planned Parenthood Waterloo Region,, and has taught sexuality classes at the University of Waterloo. She has a Master of Science from the University of Guelph and is thinking about completing a PhD.

Your alarm goes off at 7 a.m. You stumble to the bathroom to get ready for your day. You have been trying to eat healthy so you have a grapefruit for breakfast.
You also take your birth control pill, as you do every day at 8 a.m. because the pill must be taken every day at the same time to be effective.

But you’re worried because your period is late, so you take a pregnancy test to be on the safe side – and you’re pregnant, despite always taking your pill every day at the same time.

The grapefruit is the culprit. Grapefruits, as well as grapefruit juice, can interfere with the way the body metabolizes medications. This is seldom mentioned when discussing birth control pills.

It’s not the only thing that can interfere with hormonal birth control. Antibiotics, antacids such as Tums, antihistamines, anticonvulsants, antidepressants, sedatives, muscle relaxants and St. John’s Wort (to name a few) can make the pill less effective.

It is also important to be aware that no method of birth control is 100 per cent effective. Not even getting a tubal ligation or a vasectomy is 100 per cent effective, although it is considered permanent.

According to the Society of Obstetricians and Gynaecologists of Canada, male sterilization is 99.9 per cent effective and female sterilization is 99.5 per cent effective. I have actually met a couple where the man had a vasectomy and the woman had her tubes tied – they were pregnant, and not very happy.

Your body weight can also play a role in the effectiveness of birth control. The patch may not be effective for women over 198 pounds. Recent research from the European pharmaceutical company HRA Pharma found that emergency contraception such as the morning after pill may not be effective for women over 176 pounds, and has reduced effectiveness for women over 165 pounds.

Canadian research has not been conducted on how weight contributes to the effectiveness of emergency contraception, however, this new research is something women should be aware of as Statistics Canada reports that 54 per cent of Canadian women are over-weight or obese.

People rely on their health care providers to offer information regarding their medication. Ask questions and be pro-active. This includes talking to your pharmacist.

If you are using hormonal birth control let a pharmacist know this when you are prescribed another medication. Ask how the two will interact and if the effectiveness of the birth control will be diminished. Also ask about over-the-counter medications. Collect information about natural medications, vitamins and home remedies you may be using. Street drugs can also interfere with birth control.