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.

Uterine Rupture

Uterine Rupture

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 of Radiographic 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