The current perception thresholds in normal pregnancy.

The purpose of this study was to evaluate a quantitative analysis of the nociceptive threshold, using the current perception threshold (CPT), in women with normal pregnancies and to assess the relationship between nociceptive thresholds and ovarian sex steroids. The subjects consisted of 10 women with singleton pregnancies and 14 age-matched healthy female volunteers. The CPTs (5,250, and 2,000 Hz) of the dominant ankle section were determined with a Neurometer CPT/C (Neurotron, Baltimore, MD). Blood samples were collected after these examinations, and the total 17beta-estradiol (E(2)) and progesterone concentrations in sera were measured. The present findings clearly indicated that the CPTs at 2,000 Hz in women at term in normal pregnancies were significantly higher than those in nonpregnant women (p<0.05). At 5 and 250 Hz, there was no significant difference between pregnant and nonpregnant women. While there was also no significant correlation between CPT and E(2), and progesterone, there was significant correlation between CPT and the ratio of 17 beta-estradiol/progesterone (E(2)/P) at 2,000 Hz (p<0.05, r=0.67). We suggest from these data that changes in pressure sensitivity occur at term in pregnancy, and that other factors, possibly stimulated by both E(2) and progesterone, may play an important role in this change.