Health watchdog NICE believes abortion rates would go down if more women were prescribed the coil as it is more effective than the morning after pill (pictured)
The IUD, a small, T-shaped copper device that is inserted in the uterus, also has the benefit of then providing long-term contraception which can last for up to ten years.
Health watchdog NICE – the National Institute for Health and Care Excellence – said if more women were persuaded to use coils, it would help drive down abortion rates.
But others criticised the guidance – and said morning-after pills are convenient and easy to take.
Family planning charity BPAS said the Government would do better by scrapping the £30 charge for the morning after-pill, which would enable more women to be able to take it.
NICE, however, said the coil is the best way to avoid becoming pregnant after unprotected sex.
The coil, which is inserted by a nurse or doctor, is more than 99 per cent effective, works as soon as it is in place, and does not require a women to ensure they use the device correctly every day.
It can then be left in place for up to a decade, and can be quickly removed if a woman decides she wants to get pregnant.
The morning-after pill is slightly less effective – at between 98 and 99 per cent effective. But these statistics only apply if it used correctly – and is not considered to be suitable for regular use.
Professor Gillian Leng, deputy chief executive of NICE, said: 'It is really important that all contraceptive services are providing women with the best advice about contraception.
'We want to empower women with the best information about all methods of contraception and their effectiveness so they can make an informed decision.
'We also want to ensure women are told the coil is more effective than the pill as emergency contraception.'
Leicester GP Dr Jan Wake, who helped draw up the guidelines, said: 'The advantage of the coil, on top of being more effective is that it can be retained and used as long term contraception, some can even be left in place for ten years.
'Timing however is essential and women deciding on the coil should make contact with the clinic they have been advised to attend as soon as is possible.'
A coil – also known as an intrauterine device or IUD – works for five days after unprotected sex
About one in five pregnancies is unplanned – but the numbers are falling, with teenage pregnancies at their lowest level since records began.
Not all experts are impressed with the new guidance.
Ann Furedi, chief executive of BPAS, said: 'Many women are satisfied using pills and condoms.
'They do not want a coil, they simply need swift access to emergency contraceptive pills when their preferred method occasionally fails or is forgotten.
'This standard does little to improve access to emergency hormonal contraception for the many women who cannot obtain it for free under a local pharmacy scheme – and are forced either to pay up to £30 or make appointment with their GP, wasting time and resources for both the woman herself and the health service.
'Contraceptive choice is not always about which method is most effective but which is most acceptable in the context of a woman's own life and level of sexual activity.'
She added: 'Women requesting advice about contraception need information about other options, but many will have their own personal reasons for not wishing to use [devices] such as coils or implants, even if these may be ideal for others.