EMG Studies Are Not Contraindicated in Pregnancy
There are no known contraindications for EMG examination during pregnancy. 1
Safety Evidence
The available evidence strongly supports the safety of electrical stimulation and electromyographic studies in pregnancy:
Animal studies demonstrate no adverse fetal effects: Electrical stimulation applied to pregnant rats for 7 hours daily throughout gestation (Day 4 to Day 20) showed no difference in fetal body weight, resorptions, or malformations compared to controls, with no abortions observed in any stimulated animals. 2
Clinical use in pregnancy is well-established: Uterine EMG has been successfully used as a non-invasive monitoring tool to evaluate uterine electrical signals from the abdominal surface throughout pregnancy, with studies demonstrating its utility in assessing uterine and cervical function to improve patient management. 3
Pelvic floor EMG is routinely performed: Surface electromyography has been used to evaluate pelvic floor muscle function in pregnant women during the third trimester without reported safety concerns, demonstrating its acceptance as a diagnostic tool in this population. 4
Clinical Context and Practical Considerations
While EMG is safe in pregnancy, clinicians should be aware of physiologic changes that may affect interpretation:
Placental location influences signal quality: When recording uterine EMG through the abdominal wall, the placental implantation site affects the electrical activity detected, particularly when electrodes are placed directly above the placenta (lower RMS, higher median frequency). 5 This is relevant for interpretation but does not represent a safety concern.
No need for pregnancy termination if inadvertently performed: The evidence explicitly states that termination of pregnancy is not advised when electrical stimulation has been performed inadvertently in early pregnancy. 2
Comparison to Other Relative Contraindications
Unlike anticoagulation, which represents a relative contraindication to needle EMG due to bleeding risk 6, pregnancy itself poses no such concern. The procedure can be performed at any gestational age without modification.
Bottom line: Proceed with EMG studies when clinically indicated in pregnant patients without hesitation or special precautions beyond standard technique.