Ask Dr Miriam

Q I take the contraceptive pill and I want to continue but I’ve read some pills have a greater risk of causing blood clots than others. Which should I take? A There’s a tiny risk of DVT and pulmonary embolism linked to combined oral contraception according to the doses of the two hormones, oestrogen and progesterone.

The latter is often called progestogen which is a synthetic form of progesterone because the natural one can’t be absorbed by mouth. A study looking at 2,000 patients who developed a clot while taking the pill revealed that for the same progestogen a particular dose of oestrogen was linked to lower risk. The results suggest with the progestogen (levonorgestrel) a 20 microgram dose of oestrogen is the combination with the lowest overall clot risk. Talk to your GP about using a pill with these doses of hormones.