Practitioners are taught during the seminar that FSM should not be used on patients known to be pregnant. TENS devices are not to be used to run current through a pregnant uterus but FSM carries and additional self-imposed recommendation that FSM not be used once a woman is known to be pregnant. No problems have ever been observed in a patient treated who was found later to have been pregnant at the time of treatment so the recommendation is based on prudence rather than negative experience. The dramatic reductions in cytokines and prostaglandins seen with use of certain frequencies may have an unpredictable effect on the prostaglandins required to maintain a pregnancy. The dramatic order of magnitude changes in neuropeptides seen in the treatment of fibromyalgia from spine trauma may have an unintended effect on a developing fetal nervous system once the fetal nervous system is developed beyond 8 weeks, the time at which most women know they are pregnant.