If you are planning to have surgery in the coming weeks, you might want to consider holding off until August.

July is the month during which new doctors, fresh out of medical school, begin their residencies in teaching hospitals across the country. And while the enthusiasm of young, eager doctors might boost hospital morale, the inexperience of first-year residents apparently can lead to a substantial increase in rates of medical error during their first few weeks on the job.

A study released last year by the University of California at San Diego reveals that the so-called “July Effect” is real, according to ABC News.

Researchers from UCSD analyzed more than 62 million death certificates filed between 1979 and 2006. According to those certificates, 244,388 patient deaths were caused by hospital medical errors. Each month of the year saw roughly the same number of fatal medical errors, except July, when there was a reported 10 percent increase in fatal medication error.

“There are a lot of new caregivers in July,” Dr. Joanne Conroy, chief healthcare officer for the Association of American Medical Colleges, said in an interview with Hospitals PR News last year. “It’s probably a time where there are a lot of health professionals assuming new responsibilities.”

Apart from the sheer inexperience of the new residents, experts also cite the effects of adjusting to long 36-hour shifts as a possible source of medical error. Sleep deprivation in combination with being forced to tackle a sharp learning curve can result in frequent miscommunication or careless errors.

Though the chance for human error in hospitals will always exist, teaching hospitals have taken extra safety steps since the study’s release, officials say. Some are employing the use of additional computer software to check for prescription and dosage errors. Others are simply encouraging more experienced doctors to keep an especially close eye on their mentees.