Effect of Obesity on Length of Labor in Nulliparous Women

Abstract

We compared the duration of labor among nulliparous women with varying body mass index (BMI). Laboring nulliparous women at >37 weeks were included. First visit BMI was used to categorize weight as normal (≤24), overweight (25 to 29.9), or obese (≥30 kg/m²). Chi-square, one-way analysis of variance, and Bonferroni multiple comparisons tests were used. During 15 months, 375 women met the inclusion criteria, and 38% were obese. Duration of first stage of labor was significantly longer for obese versus normal-weight women (26.76 ± 0.77 versus 23.87 ± 0.66 hours; p = 0.024) but not between normal versus overweight women (p = 1.00) or overweight versus obese women (p = 0.114). The cesarean delivery rate was significantly different in the three groups (p = 0.0001), highest among obese (47%) and lowest in normal-weight women (24%). When adjusted for age, hypertension, and induction, the likelihood of completing stage I was significantly less among obese nulliparous than those with BMI < 24 kg/m² (hazard ratio 0.73, 95% confidence intervals 0.54, 0.99). Compared with those with BMI < 24, the duration of stage I is significantly longer among obese women, even when adjusted for maternal age, induction, and hypertension.

Keywords

body mass index - labor - obesity

• References

• 1 American College of Obstetricians and Gynecologists. ACOG Committee Opinion number 315, September 2005. Obesity in pregnancy. Obstet Gynecol 2005; 106: 671-675
• 2 American College of Obstetricians and Gynecologist; . Dystocia and augmentation of labor. Clinical management guidelines for obstetricians–gynecologists: practice bulletin No. 49. Washington, DC: ACOG ; 2003
• 3 American College of Obstetricians and Gynecologist; . Intrapartum fetal heart rate monitoring—gynecologists: practice bulletin No. 70. Washington, DC: ACOG ; 2005
• 4 Vahratian A, Zhang J, Troendle JF, Savitz DA, Siega-Riz AM. Maternal prepregnancy overweight and obesity and the pattern of labor progression in term nulliparous women. Obstet Gynecol 2004; 104 (5 Pt 1) 943-951
• 5 Weiss JL, Malone FD, Emig D , et al; FASTER Research Consortium. Obesity, obstetric complications and cesarean delivery rate—a population-based screening study. Am J Obstet Gynecol 2004; 190: 1091-1097
• 6 Young TK, Woodmansee B. Factors that are associated with cesarean delivery in a large private practice: the importance of prepregnancy body mass index and weight gain. Am J Obstet Gynecol 2002; 187: 312-318 ; discussion 318–320
• 7 Baeten JM, Bukusi EA, Lambe M. Pregnancy complications and outcomes among overweight and obese nulliparous women. Am J Public Health 2001; 91: 436-440
• 8 Sheiner E, Levy A, Menes TS, Silverberg D, Katz M, Mazor M. Maternal obesity as an independent risk factor for caesarean delivery. Paediatr Perinat Epidemiol 2004; 18: 196-201
• 9 Sebire NJ, Jolly M, Harris JP , et al. Maternal obesity and pregnancy outcome: a study of 287,213 pregnancies in London. Int J Obes Relat Metab Disord 2001; 25: 1175-1182
• 10 Rooney BL, Schauberger CW. Excess pregnancy weight gain and long-term obesity: one decade later. Obstet Gynecol 2002; 100: 245-252
• 11 Jie Zhang, Kendrick A, Quenby S, Wray S. Contractility and calcium signaling of human myometrium are profoundly affected by cholesterol manipulation: implications for labor?. Reprod Sci 2007; 14: 456-466
• 12 Moynihan AT, Hehir MP, Glavey SV, Smith TJ, Morrison JJ. Inhibitory effect of leptin on human uterine contractility in vitro. Am J Obstet Gynecol 2006; 195: 504-509
• 13 Buhimschi CS, Buhimschi IA, Malinow AM, Weiner CP. Intrauterine pressure during the second stage of labor in obese women. Obstet Gynecol 2004; 103: 225-230
• 14 Zhang J, Troendle J, Reddy UM , et al; Consortium on Safe Labor. Contemporary cesarean delivery practice in the United States. Am J Obstet Gynecol 2010; 203: 326, e1-e326, e10