First stage of labor in multiparous women with shoulder dystocia

Abstract

SHOBHA MEHTA, EMILY HAMILTON, EMMANUEL BUJOLD, SEAN BLACKWELL, Wayne State University, Obstetrics/Gynecology, Detroit, Michigan, McGill University, Montreal, Quebec, Canada OBJECTIVE: The purpose of this study was to evaluate the progression of the first stage of labor in multiparous women complicated by shoulder dystocia (SD). STUDY DESIGN: Deliveries diagnosed with shoulder dystocia from 1/1996-1/ 2001 at a single institution were identified from ICD-9 codes and confirmed by chart review. Each pregnancy was matched 1:1 to a control patient that had vaginal delivery based on four factors: maternal parity, neonatal birth weight within 200 g, labor induction and maternal race. Labor progress was quantified using a mathematical model that compared dilations in the study groups to a reference population adjusting at each exam for parity and changing conditions such as contraction frequency, epidural use and the state of the cervix at the previous examination. Statistical methods included paired t test, Wilcoxon rank sum and c. RESULTS: Of 16,084 multiparous patients meeting inclusion criteria, 141 patients (0.9%) had SD. Neurological injury occurred in 14.2%. There were no differences between SD cases and controls for admission mean dilation (4.1 vs. 4.3 cm, P = .50), effacement (70 vs. 71%, P = .85), station ( 2.3 vs. 2.4, P = .25) or the length of the first stage (8.3 vs. 7.1 hrs, P = .15). The average percentile of all exams, however, was lower (31.5 vs. 25.2 %, P = .003). There were more examinations that ranked below the 5th percentile (31.0 vs. 23.5%, P = .012) and below the 3rd percentile (24.6 vs.15.8%, P= .001). CONCLUSION: Despite beginning labor in a similar state these multiparous women with SD had slower labors compared to their matched controls. This was more evident using a measure that adjusts for contraction frequency than a simple duration of first stage. 277 INTERVAL BETWEEN PREGNANCIES AND MATERNAL AGE: THEIR IMPACT: ON PREGNANCY OUTCOME THOMAS MYLES, HEATHER VOLK, LINDA MUNDY, TERRY LEET, Saint Louis University, Obstetrics and Gynecology, St. Louis, Missouri, Saint Louis University, School of Public Health, St. Louis, Missouri, Washington University in St. Louis, St. Louis, Missouri, Saint Louis University, Community Health, St. Louis, Missouri OBJECTIVE: Advanced maternal age (AMA) and short/long interpregnancy intervals (IPI) have been shown to be independently associated with increased risk for adverse perinatal outcomes. The interaction effect of age and IPI as risks for adverse perinatal outcomes has not been characterized. STUDY DESIGN: This population-based cohort study examines the relationship between AMA (age R35), IPI, and the interaction between these 2 factors on pregnancy, fetal, and neonatal outcomes in the 2nd pregnancy. The study population included women enrolled in the Missouri maternally-linked cohort between 1/89-12/97. Of the 313,784 patients with R2 deliveries, 75,527 met final inclusion criteria. Only subjects >20 years of age at first birth and with singleton or twin births were eligible. Adjusted odds ratios (OR) and 95%confidence intervals (CI) were calculated using logistic regression, with adjustments for nonindependent events. RESULTS: AMA (n = 2105) at first pregnancy increased risk for gestational diabetes (GDM) (OR 1.7, CI 1.3-2.2), placenta previa (2.0, 1.3-2.3), very low birth weight (VLBW) (1.7, 1.2-2.6), macrosomia (M) (1.2, 1.02-1.3), and preterm delivery (PTD) (1.4, 1.2-1.6). IPI !6 months significantly increased risk for PTD.(2.0, 1.01-4.0); IPI of 6-18 months decreased risk for GDM (OR 0.7 [0.60.9]) and M (0.8, 0.8-0.9) and increased risk for fetal death (1.7, 1.3-2.3), VLBW (1.9, 1.8-2.3), and PTD (1.7, 1.2-2.3); IPI of 24-48 months increased risk for small for gestational age infants (1.2, 1.1-1.3) and M (1.1, 1.05-1.14). For IPI >48 months there was increased risk for GDM (1.4, 1.2-1.6), and VLBW (1.4, 1.1-1.8). After adjusting for demographic factors and IPI, the risks for AMA patients were increased for PTD (1.2, 1.01-1.5) and M (1.2, 1.1-1.4). No interaction between AMA and IPI was found for the other variables studied. CONCLUSION: AMA and IPI were independently associated with risk for adverse perinatal outcomes. Strategically spacing childbirth around life events for the older woman will not bring any additional risk or benefit.