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

ResultsSplint 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

Results4,833,286 deliveries10,316 (0.2%) met study criteria2,494 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)

ResultsFalls were the most common

mechanism MVA 2nd most commonMVA most common mechanism that

lead to admissionAssault third most common mechanism

and cause of admission

ResultsGestational 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 LimitationsRetrospective, 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 AbruptionUterus consists of many elastic fibers

The placenta has very few elastic fibers

This causes an inelastic connection

Uterine Rupture0.6% of all injuries during pregnancyVarious degrees ranging from seosal

hemorrhage to complete avulsion75% of cases involve the fundusFetal 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 unknowEstimated 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