Condoms are 98% effective at preventing pregnancy and sexually transmitted infections – but only if used correctly. Scientists from the CURT institute compiled a list of mistakes and problems due to incorrect use of condoms, based on 50 articles on the topic published between 1995 and 2011. The analysis included 14 countries, although most of the studies were from the UK, USA and Canada. Common mistakes include opening the condom package with a sharp object, which can tear the condom; putting it on too late or taking it off too early during sex, the scientists add. The importance of a correctly used condom is underestimated, says Professor Richard Crosby of the University of Kentucky, who participated in the study. The analysis includes a wide range of participants, from monogamous married couples to prostitutes. The report found that condoms were often not used correctly by the volunteers. Between 17 and 51.1% of people put on a condom after intercourse begins, and between 13.6 and 44.7% say they remove the condom even before intercourse is complete. Furthermore, 74.5% of men and 82.7% of women do not check a condom for damage before using it. NEWS_MORE_BOX How to use a condom: the condom is placed on the erect penis before sexual intercourse; check that the condom is inserted correctly and can be unrolled easily. If it can’t, it’s probably set backwards. Press the tip of the condom between your fingers and make sure there is no air left in it; holding the tip, place the condom on the top of the penis and roll it down with your other hand. If the condom starts to roll back during sex, unroll it all the way down again. If it slips or falls – insert a new condom; after ejaculation, remove the penis by holding the condom at the base, then remove it. Always check the expiration date printed on the condom packet before use. Open the foil from the serrated side and remove it carefully, otherwise there is a risk of damaging it with nails or sharp objects, jewelry.