Factors influencing maternal perception of uterine contractions

Objectives: The purpose of this study was to assess factors associated with perception of uterine contractions. Study design: A database of ambulatory uterine activity monitoring was examined. All patients having singleton pregnancies evaluated between March 1997 and March 2002 were eligible for analysis. Data were divided into 4 groups by maternal prepregnancy body mass index (BMI): lean (< 20 kg/m²), normal (≥ 20 to < 25 kg/m²), overweight (≥ 25 to < 30 kg/m²), and obese (≥ 30 kg/ m²). The percentage of contractions perceived during observation was compared between groups. Variables interrogated included maternal weight and parity. Statistical analysis included t test, analysis of variance (ANOVA), and linear regression. Results: Data from 7808 patients (556,382 hr) were analyzed. A significant reduction in perception of contractions occurred with increasing BMI between each classification, P < .001. A significant reduction in perception of contractions was also noted between nulliparous and multiparous patients at each weight classification, P < .001. Conclusion: Obese, nulliparous patients have the greatest difficulty perceiving contractions. Such data may help explain unattended birth or late presentation for care in this group.