1. Blunt Trauma in the Pregnant Woman
Bill Schroeder DO
Stanford Emergency Medicine

2. 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

3. Physiologic Changes in Pregnancy
Grossman NB. Blunt trauma in pregnancy. Am Fam Physician Oct 1;70(7):

4. 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 Oct 1;70(7):
Morris JA Jr, et al. Infant Survival after Cesarean Section for Trauma. Ann Surg 1996;223:

5. 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

6. 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

7. 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 ( )
Methods: Vital Statistics-Patient Discharge Database (VS/PDD)
Compiled from hospitals reporting to the California Office of Statewide Health Planning and Development

8. 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

9. 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)

10. 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

11. 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

12. 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

13. 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

14. 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 % of pregnant woman in severe traumas compared to 1-5% in minor trauma

15. Why does Fetal Demise Occur?
Grossman NB. Blunt trauma in pregnancy. Am Fam Physician Oct 1;70(7):

16. Placental Abruption Uterus consists of many elastic fibers
The placenta has very few elastic fibers
This causes an inelastic connection

17. 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.

18. Uterine Rupture

19. Uterine Rupture

20. 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

21. Proposed Algorithm for Management of the Pregnant Woman after Trauma
Grossman NB. Blunt trauma in pregnancy. Am Fam Physician Oct 1;70(7):

22. Radiation risk to fetus
Toppenberg KS, et al. Safety of Radiographic Imaging During Pregnancy. Am Fam Physician Apr; 59(7):

23. 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 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 rads to double the baseline mutation rate
Toppenberg KS, et al. Safety of Radiographic Imaging During Pregnancy. Am Fam Physician Apr; 59(7):

24. Number of studies to exceed dangerous level of radiation
Toppenberg KS, et al. Safety of Radiographic Imaging During Pregnancy. Am Fam Physician Apr; 59(7):

25. References
Grossman NB. Blunt trauma in pregnancy. Am Fam Physician Oct 1;70(7):
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:
Morris JA Jr, et al. Infant Survival after Cesarean Section for Trauma. Ann Surg 1996;223:
Pearlman MD, Phillips ME. Safety belt use during pregnancy. Obstet Gynecol 1996;88:
Shah KH, Simons RK, Holbrook T, Fortlage D, Winchell RJ, Hoyt DB. Trauma in pregnancy: maternal and fetal outcomes. J Trauma Jul;45(1):83-6.
Toppenberg KS, et al. Safety of Radiographic Imaging During Pregnancy. Am Fam Physician Apr; 59(7):
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