Reduced pain tolerance during and after pregnancy in women suffering from fear of labor

Abstract

Pain tolerance in women suffering and not suffering from fear of labor during and after pregnancy were compared. Twenty women with labor fear and 20 control women were subjected to a cold pressor test (CPT) on average 1 month before delivery and 9 months later. Half the volunteers were nulliparous and half parous. Pain endurance time (PET) and intensity of pain (Visual Analogue Scale, VAS) during CPT was assessed. Patients in the fear group tolerated CPT for a significantly shorter time than did women without fear both in pregnancy (154.8±109.9 s vs. 282.5±60.1 s (mean±SD), P<0.001), and in the postpartum period (128.6±111.7 s vs. 279.6 ±60.3 s, P=0.002). Those with labor fear experienced CPT as significantly more painful than did the controls both during pregnancy (VAS 6.68±1.9 vs. 3.78±2.0 (mean±SD), P<0.001) and after (VAS 7.73±1.5 vs. 5.92±3.0, P=0.04). PET and VAS values correlated during pregnancy ( r=−0.62, P<0.001), but not after pregnancy ( r=−0.30, not significant). Parity was not associated with either PET or VAS scores. As a rule, pain in all women during CPT was regarded to be lower during pregnancy than after pregnancy (VAS 4.87±2.4 vs. 6.60±2.6, P=0.001). Patients with fear of labor were characterized by pain intolerance also in circumstances other than labor. This fact may indicate enhanced sensitivity to pain-causing mechanisms in women who develop fear of labor.