If you know any first-time expectant moms nervous about a long, painful childbirth, they may be reassured by a new study that suggests she probably won’t remember most of it anyway. Researchers from Israel have found that regardless of whether labor lasts 12 minutes or 12 hours, most mothers only remember two parts of the experience: the peak and the end.

A team of researchers from the Open University of Israel conducted a study recently to see if memories of childbirth were significantly influenced by either the length of actual childbirth or whether or not the mother had an epidural. According to the press release, the scientists accompanied 320 women in the delivery room and asked each one to rate her pain every 20 minutes on a scale of one (no pain) to 100 (the worst imaginable pain). The researchers then called the new mothers two days and then two months after the delivery and asked each one to use the same pain scale and provide an overall evaluation of labor pain from the moment she entered the delivery room until she gave birth.

Results showed that the overall length of the delivery had no significant influence on a mother’s recollection of the pain. Rather it was the peak and end levels of pain that remained in the new mother's memories, something that surprised the scientists. “This phenomenon, called duration neglect, is particularly interesting given the common use of epidural analgesia," explained Eran Chajut, one of the researchers involved in the study.

Duration neglect, also known as the peak-end rule, is a mechanism that humans have evolved to use to deal with many different types of pain. The rule is quite self-explanatory and means that in most instances of human pain, ranging from child birth to heartbreak, we tend to recall our overall experiences based only on the peak sensation and how we felt at the very end. It allows us to do many extraordinary things, such as in the example provided by io9: climbing Mount Kilimanjaro. After the experience, an individual will become hazy on how uncomfortable they felt in the long, arduous journey up and only remember how it felt to be on the summit (the peak) and how it felt to have accomplished their goal (end).

The factors of peak and end pain accounted for around 40 percent of the variation in a woman’s pain rating. According to the researchers, this finding proves as evidence of the effectiveness of the epidural in preventing not only delivery pain, but also minimizing the later recollection of this pain. "In our study, mothers who received an epidural remembered their pain as relatively moderate — on average they rated their pain at around 70 after two days and about 65 after two months," Chajut said. This may be due to the fact that the women who receive this drug are less likely to feel pain at the end of the delivery and thus less likely to remember the pain of the overall experience.

Source: Chajut E, Caspi A, Chen R, Hod M, Ariely D. In Pain Thou Shalt Bring Forth Children: The Peak-and-End Rule In Recall of Labor Pain. Psychological Science. 2014.