Visual evoked potential responses in pregnant women.

Sensory functions and their electrophysiological correlates have not been adequately documented during pregnancy. The present study reports visual evoked potential responses to pattern reversal (VEP-P) in ten third trimester pregnant women and changes in latency of NPN complex when compared with these responses in the non pregnant state. Visual evoked potentials were recorded from O1-A1 and O2-A2 scalp areas, using Ag/Agcl disc electrodes to transient pattern of black and white checkerboard with 32' size and reversal rate 1Hz. Two trials of VEP-P responses to 256 transient pattern stimuli given to each eye, were analysed and averaged by the computer of visual evoked potential recorder (MEB 5200 Nihon Kohden Japan). The latencies of various positive and negative waves, along with P1 amplitude, obtained in pregnant women, were compared with those obtained in ten non-pregnant women. The latencies of initial NPN complex (N1P1 & N2) were significantly reduced in pregnant women, indicating that pregnancy facilitates conduction process in the optic pathways.