It’s not something most of us want to think about. After all society — from alcohol commercials to Dr. Ruth—promotes sex as a pleasurable activity that’s a natural part of life. For the most part, they’re right.

Unfortunately, in some cases sex can lead to conditions that will kill you. These situations are rare, but it’s a good idea to learn about them so you can reduce your risk.

1. STIs Reduce Life Expectancy

The most common way to contract a sexually transmitted infection (STI) is through unprotected sex. These diseases include genital herpes, hepatitis B, chlamydia, syphilis, gonorrhea, and HIV/AIDS. The American Social Health Organization states that 25 per cent of teens are infected with an STI every year, and 50 per cent of sexually active adults 25 and over will contract one.

The deadliest STI is human immunodeficiency virus or HIV, which causes AIDS or acquired immune deficiency syndrome. Drugs can control the disease and prolong your life expectancy. However, without proper medical attention most people die within 10 to 15 years of being infected.

Another STI that reduces life expectancy is genital humanpapilloma virus (HPV). It is the most common STI in the US and can cause cervical, genital, or anal cancer. According to the American Cancer Society the overall five-year survival rate for cervical cancer is 72 per cent.

Many STIs don’t have immediate symptoms, so get tested regularly if you’re sexually active. Also, practice safe sex or abstinence, and always ask new partners to get tested.

2. Medical Conditions Can Increase Risk

You may have heard about someone dying during sex. These cases are rare and usually are related to a pre-existing condition. The American Journal of Cardiologystates that sexual activity triggers about one per cent of heart attacks, usually when a heart problem is already present.

You should avoid sex if you suffer from angina, uncontrolled hypertension, arrhythmias, cardiomyopathy (weak heart muscle), advanced heart failure, or if you’ve had a heart attack in the last two weeks.

3. Some Aphrodisiacs Are Risky

For centuries people have used stimulants to spice up their sex lives. However, they can also put an end to all your pleasure. In the 1990s the U.S. Food & Drug Administration (FDA) banned Spanish Fly after several deaths were linked to the aphrodisiac. In the late 90s and early part of this decade several people suffered heart attacks and died after using Viagra.

In 2008 New York health officials issued a warning about “The Stone,” after a man died using it. It’s made from toad venom and is also called Piedra, Black Stone, Chinese Rock, Jamaican Stone, or Love Stone. The FDA banned it, but it’s still available in some sex shops.

Before using any sex enhancer make sure you know the risks, especially if you have a medical condition such as heart disease or high blood pressure.

4. Latex Condoms Can Be Lethal

Condom usage has skyrocketed since the awareness of HIV/AIDS. Latex condoms are the most popular, but some people are allergic to latex. In severe cases anaphylactic shock occurs and is fatal without immediate medical attention.

If you’ve experienced a reaction to latex gloves stay away from latex condoms. If you’re not sure about your risk, get tested by a doctor. For those who are allergic there are alternatives. For men there are polyurethane condoms, and women can use polyurethane vaginal condoms, or a sponge or diaphragm combined with a spermicide.

5. Sex During Pregnancy is Safe, with a Few Exceptions

Concerns about hurting mother or baby during sex are often unwarranted. A healthy pregnant woman can have sex right up to delivery.

However, avoid inserting anything into the vagina as this can cause injuries or infections dangerous to both mother and baby. If you have a cervical prolapse or leak amniotic fluid, you should avoid sex.

Blowing into the vagina is also dangerous. It can force an air bubble into the expectant mother’s bloodstream. If the bubble reaches the heart it can cut off blood flow to the lungs, causing death.