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Blunt Trauma in the Pregnant Woman. Bill Schroeder DO Stanford Emergency Medicine. Introduction. Trauma occurs in 6-7% of pregnancies in US Leading nonobstetric cause of maternal death
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Blunt Trauma in the Pregnant Woman Bill Schroeder DO Stanford Emergency Medicine
Introduction • Trauma occurs in 6-7% of pregnancies in US • Leading nonobstetric cause of maternal death • Female drivers are more likely to be in a MVA than male drivers: 84 vs 73 drivers per 10 million miles driven ACOG educational bulletin. Obstetric aspects of trauma management. Number 251, September 1998 (replaced Number 151, January 1991, and Number 161, November 1991). Int J Gynecol Obstet 1999;64:87-94
Physiologic Changes in Pregnancy Grossman NB. Blunt trauma in pregnancy. Am Fam Physician. 2004 Oct 1;70(7):1303-10.
Pregnant woman can lose 30% (2L) of blood volume before vital signs change • At 30 wks GA the uterus is large enough to compress the great vessels causing • up to a 30mm Hg drop in systolic BP • 30% drop in stroke volume • A series of 441 pregnant trauma victims with no detectable fetal heart tones showed no fetal survivors. • Grossman NB. Blunt trauma in pregnancy. Am Fam Physician. 2004 Oct 1;70(7):1303-10. • Morris JA Jr, et al. Infant Survival after Cesarean Section for Trauma. Ann Surg 1996;223:481-91.
Seat Belts • Nearly 20% of pregnant woman surveyed never or rarely used seat belts • 22% used them incorrectly • Proper placement of the lap belt is: • As low as possible on the pregnancy bulge across the ASIS and pubic symphysis • Placement on the uterus causes a 3-4x increase in force transmitted to the uterus • Shoulder harness should be positioned between the breasts Pearlman MD, Phillips ME. Safety belt use during pregnancy. Obstet Gynecol 1996;88:1026-9
ACOG recommendations • “There is substantial evidence that seat belt use during pregnancy protects both the mother and the fetus” • “Airbag deployment does not appear to be associated with increase risk for either maternal or fetal injury” • Though based on limited data ACOG educational bulletin. Obstetric aspects of trauma management. Number 251, September 1998 (replaced Number 151, January 1991, and Number 161, November 1991). Int J Gynecol Obstet 1999;64:87-94
Large Population Study • Kady EL, et al. Trauma during Pregnancy: An ananlysis of maternal and fetal outcomes in a large population. Am J OB and GYN 2004;190:1661-8 • Objective: to determine occurrence rates, outcomes, risk factors and timing of obstetric delivery for trauma during pregnancy • Design: retrospective cohort study (1991-1999) • Methods: Vital Statistics-Patient Discharge Database (VS/PDD) • Compiled from hospitals reporting to the California Office of Statewide Health Planning and Development
Results • Splint into two groups • Group 1: deliveries at the time of trauma hospitalization • Group 2: trauma sometime within the 9 months preceding the delivery • Control: all deliveries not involved in trauma • Fetal demise prior to 20 weeks gestation not included in this study
Results • 4,833,286 deliveries • 10,316 (0.2%) met study criteria • 2,494 at the time of the trauma, group I (0.52/1,000 deliveries) • 7,822 during the 9 months prior to trauma, group II (0.78/1,000 deliveries)
Results • Falls were the most common mechanism • MVA 2nd most common • MVA most common mechanism that lead to admission • Assault third most common mechanism and cause of admission
Results • Gestational age was the strongest predictor of fetal, neonatal and infant death • What and how severe the trauma was not as strong a predictor as gestational age • Highest risk at <28 weeks gestation
Results • Group 2 women had increased morbities compared to controls including: • Abruption • Premature delivery • Low birth weight • Trauma may cause subclinical, chronic plancenta abruptions • causing insufficient uterine blood supply • Woman involved in a trauma during pregnancy need close monitoring during labor
Study Limitations • Retrospective, population-based study • Only hospitalized patients • Cannot extend to minor traumas not requiring hospitalization • Did not include pregnancy loss prior to 20 weeks gestation
Fetal Demise • Rate of fetal demise after blunt trauma 3.4-38% • Lead causes • Placental abruption • Maternal shock • Maternal death • 1,300-3,900 pregnancies are lost due to trauma each year • Abruption occurs in 40-50% of pregnant woman in severe traumas compared to 1-5% in minor trauma
Why does Fetal Demise Occur? • Grossman NB. Blunt trauma in pregnancy. Am Fam Physician. 2004 Oct 1;70(7):1303-10.
Placental Abruption • Uterus consists of many elastic fibers • The placenta has very few elastic fibers • This causes an inelastic connection
Uterine Rupture • 0.6% of all injuries during pregnancy • Various degrees ranging from seosal hemorrhage to complete avulsion • 75% of cases involve the fundus • Fetal mortality approaches 100% • Maternal mortality 10% • Usually due to other injuries Weintraub AY, Leron E, Mazor M. The Pathophysiology of Trauma in Pregnancy: A Review. J Mat-Fet and Neo Med 2006;19(10):601-5.
Preterm Labor • Incidence following trauma is unknow • Estimated to be under 5% • Theory: caused by destabilization of lysosmal enzymes that initiate prostaglandin production • Consider admistering slow-released progesterone for all woman with contracts after trauma
Proposed Algorithm for Management of the Pregnant Woman after Trauma • Grossman NB. Blunt trauma in pregnancy. Am Fam Physician. 2004 Oct 1;70(7):1303-10.
Radiation risk to fetus Toppenberg KS, et al. Safety of Radiographic Imaging During Pregnancy. Am Fam Physician. 1999 Apr; 59(7):1813-18
Radiation and Pregnancy • Risk of spontaneous abortion, major malformations, mental retardation and childhood malignancy 286 per 1,000 deliveries. • Exposure of 0.5 rads adds only 0.17 cases per 1,000 deliveries ( 1 in 6,000) • American College of Obstetricians and Gynecologist have stated that exposure to x-rays during a pregnancy is not an indication for therapeutic abortion • Fetus is at greatest risk at 10-17 weeks of gestation as this is key in neurodevelopment. • Malignancy exposure to 1-2 rad increases Leukemia from 3.6/1000 to 5/1000 • It takes 50-100 rads to double the baseline mutation rate Toppenberg KS, et al. Safety of Radiographic Imaging During Pregnancy. Am Fam Physician. 1999 Apr; 59(7):1813-18
Number of studies to exceed dangerous level of radiation Toppenberg KS, et al. Safety ofRadiographic Imaging During Pregnancy. Am Fam Physician. 1999 Apr; 59(7):1813-18
References • Grossman NB. Blunt trauma in pregnancy. Am Fam Physician. 2004 Oct 1;70(7):1303-10. • Kady EL, et al. Trauma during Pregnancy: An ananlysis of maternal and fetal outcomes in a large population. Am J OB and GYN 2004;190:1661-8. • Morris JA Jr, et al. Infant Survival after Cesarean Section for Trauma. Ann Surg 1996;223:481-91. • Pearlman MD, Phillips ME. Safety belt use during pregnancy. Obstet Gynecol 1996;88:1026-9. • Shah KH, Simons RK, Holbrook T, Fortlage D, Winchell RJ, Hoyt DB. Trauma in pregnancy: maternal and fetal outcomes. J Trauma. 1998 Jul;45(1):83-6. • Toppenberg KS, et al. Safety of Radiographic Imaging During Pregnancy. Am Fam Physician. 1999 Apr; 59(7):1813-18. • Weintraub AY, Leron E, Mazor M. The Pathophysiology of Trauma in Pregnancy: A Review. J Mat-Fet and Neo Med 2006;19(10):601-5. • ACOG educational bulletin. Obstetric aspects of trauma management. Number 251, September 1998 (replaced Number 151, January 1991, and Number 161, November 1991). Int J Gynecol Obstet 1999;64:87-94