A The morning-after pill is effective only up to 72 hours after intercourse but the level of protection declines dramatically during that time. In the first 24 hours it prevents 95 per cent of pregnancies, but that figure drops to 85 per cent within the next 24 hours and only 58 per cent if taken after that. Using the morning-after pill twice in one month does suggest that you ought to be investigating a more reliable form of contraception and that you have not used a condom means that you may have exposed yourself to sexually transmitted infections (STIs). However, in terms of safety, there is no medical evidence to indicate that taking it more than once in a cycle will cause you any long-term health problems.

Our own Dr Mark Porter describes it as “incredibly safe”, though he emphasises the need for other forms of contraception. That said, the morning-after pill can disrupt the regularity of your menstrual cycle, and since getting your period is your main way of knowing whether you are pregnant or not, using it more than once in a month can increase your level of uncertainty until your period arrives.

The majority of over-the-counter sales of the morning-after pill are to responsible mid-twenties urban professionals who don’t want to run the risk of an unplanned pregnancy. Before they are given the tablet, most of them are grilled about their sexual behaviour and are usually advised to go on the Pill. Many women avoid the Pill because it doesn’t agree with them or makes them gain weight, while single women question the validity of pumping themselves full of hormones on the off chance that they will have sex, at some point in the future, with a man they have yet to meet. Bar condoms, which have a 15 per cent failure rate because of product defects and user errors, IUDs provide the only hormone-free method of contraception, but they are painful to insert and remove, and can make periods heavier and more painful. One in every three women in Britain has a termination before the age of 45.

Ann Furedi, of the British Pregnancy Advisory Service (BPAS), says that “for women who are not in a relationship, the morning-after pill is even safer than the contraceptive pill because it is only an occasional dose of hormones, although obviously it doesn’t protect against STIs”. The BPAS states that “there is no limit” to how many times you can use it.

Because time is crucial to the effectiveness of the morning-after pill the Family Planning Association (FPA) believes that women should be encouraged to keep emergency contraception in the same way that people keep a supply of paracetamol or antihistamines. An FPA survey revealed that although 75 per cent of women would like to have emergency pills in advance, more than 80 per cent did not know they could ask for this. After the FPA survey there was concern from MPs and religious groups about how availability might encourage unprotected sex, but in 2007 a review by the emergency contraception experts James Trussell and Elizabeth G. Raymond reported that “evidence would seem to demonstrate convincingly that making emergency contraception pills more widely available does not increase risk-taking or adversely affect regular contraceptive use” and that “women who are the most diligent about ongoing contraceptive use are those most likely to seek emergency treatment”.

You have used emergency contraception only five or six times. If this incident heralds the start of a new relationship then consider the long-term options, but if it is a one-off, you can buy the morning-after pill in advance from some pharmacies. The pills are sold in packs of one, two or three. They are not cheap, but peace of mind is priceless.