This party season, don't find yourself with a sexually transmitted infection (STI) or an unintended pregnancy. With a little preparation, you can prevent a mishap from becoming a crisis.

Calls to the fpa sexual health helpline are often at their highest in January. Most calls are from people who have had an 'accident' during the party season because of contraception failure or unprotected sex. More teenagers become pregnant in December and January than any other months of the year. 

Rebecca Findlay of fpa says: "The helpline tends to go quiet before Christmas as everyone is busy and out partying, but calls then peak in January. Most people call about STIs or unintended pregnancy."

A bit of forward planning can stop an accident from becoming a crisis.

1 Stock up on your contraception

If you use a method of contraception that you need to take every day, such as the pill, make sure you have enough to last over Christmas, especially if you're going away.

"The classic mistake is to go away and forget to take your contraception with you, or to run out of pills on Christmas Eve," says Findlay. "To avoid this, check when your pill pack is going to run out. If it will run out while you're away, get a new one before you go. And if you're using the contraceptive injection, make sure it's up to date. Whatever contraception you use, make sure you're organised and have enough to last."

To avoid forgetting your contraception if you go away:

• put it on your list of things to pack,
• leave a note for yourself by the front door,
• set a reminder on your phone, 
• write it in your diary, or
• ask your partner or a friend to remind you.

If you don't have a regular method of contraception, such as the implant, injection or intrauterine device (IUD), consider organising one before the holidays.

2 Stock up on condoms

Keep some condoms with you. They're the only form of contraception that protects against both pregnancy and STIs. Condoms are useful to have in case you have sex with someone new, or if your regular method of contraception fails or runs out.

Vomiting can reduce the effectiveness of the pill. If you're sick, you may need to use condoms to make sure you're protected against pregnancy. The advice varies for different pills, so check the information leaflet in your pill packet, talk to your doctor or nurse, or call the fpa helpline on 0845 122 8690.

You can get free condoms from community contraceptive clinics, sexual health or GUM (genitourinary medicine) clinics, and some young people's services. You can buy condoms from pharmacies, supermarkets and vending machines.

Make sure any condoms you use have the CE mark on them. This means they meet European safety standards.

3 Know where to get emergency contraception

Emergency contraception can prevent pregnancy if you have had unprotected sex or your regular contraception has failed. Emergency hormonal contraception (the 'morning after pill') is for use in an emergency. Don't rely on it as a regular method of contraception. It doesn't work as well as regular methods of contraception at stopping unintended pregnancies.

IUDs can be fitted in an emergency to prevent pregnancy. They must be fitted by a trained doctor or nurse (at a clinic or your GP surgery).

If your contraception fails or you have unprotected sex over Christmas and the local clinics and pharmacies are closed, knowing where to get the emergency hormonal pill or IUD could make all the difference.

Where can I get emergency contraception?

• GUM (genitourinary medicine) clinics, 
• NHS walk-in centres, 
• pharmacies, and
• young people's services.

Some GP surgeries and clinics may give emergency hormonal contraception in advance, so you can take it with you if you go away.

4 Know how to find a clinic

To find a clinic:

• Look in the phone book under 'sexual health'. 
• Use the NHS Choices service search.
• Call the Sexual Health Line free on 0800 567 123.
• Call the fpa helpine on 0845 122 8690 or use fpa's clinic finder.

If you're under 25, you can call Brook on 0808 802 1234, or visit the National Chlamydia Screening Programme website to find out where you can get tests for chlamydia.

Christmas day falls on a Friday in 2009, so some clinics may be closed from Thursday until Tuesday. Call your local clinic to find out their Christmas opening hours.

You can visit any sexual health or contraceptive clinic in England. Find out the nearest or most convenient one for you and their opening hours over Christmas and New Year, whether you'll be at home or away.

5 Don't panic

Help is available if your contraception fails or you have unprotected sex over the holidays. Even if your nearest clinic or GP surgery is closed, you can go to an NHS walk-in centre or an accident and emergency (A&E) department. Some of these can provide emergency contraception and can offer advice and testing if you're worried about STIs.