According to Medical news today, here are two factors that can lead to death during sexual intercourse.
1. Cardiac Arrest

Cardiac arrest is the sudden or abrupt stopping of blood supply to the brain and other organs. There are certain sickness that can lead to loss of life during intercourse one of which is myocardial ischemia. This occurs when blood flow to the heart muscle (myocardium) is obstructed by a partial or complete blockage of a coronary artery by a buildup of plaques (atherosclerosis). Most patients who have coronary artery disease fall victim to this.

2. Using drugs without a prescription from a physician

Many people use drugs to improve their performance while getting intimate with first consulting a medical expert if it is safe for them to do so. Some times people go as far as combining opiate pain killers with alcohol. Some people go as far as using marijuana have a pleasurable copulation experience even though it might be harmful to their  health.

According to Medical news today, when coupled with a chemical that includes nitrates, some intimate enhancers have been known to produce hypotension (low blood pressure), which can be fatal.