Journal of Emergencies, Trauma, and Shock
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 Table of Contents    
SYMPOSIUM  
Year : 2011  |  Volume : 4  |  Issue : 4  |  Page : 508-510
The role of ultrasound in life-threatening situations in pregnancy


1 Women's Health Department, Al Ain Hospital, United Arab Emirates
2 Department of Obstetrics and Gynecology, Faculty of Medicine and Health Sciences, UAE University, United Arab Emirates

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Date of Submission31-May-2011
Date of Acceptance14-Jun-2011
Date of Web Publication24-Oct-2011
 

   Abstract 

Pregnant women are at an increased risk of a number of conditions that are associated with bleeding. Conditions such as ectopic pregnancy, retained products of conception, placenta previa, abruptio placentae, morbid adhesion of the placenta, and postpartum hemorrhage can be associated with massive bleeding that endangers the maternal life and health. Screening, early detection, and prevention play a key role in reducing maternal morbidity and mortality caused by these conditions. Ultrasound, in experienced hands, is an effective tool that can assist in diagnosing many of these obstetrical conditions. The advances in technology and the non-invasive nature of ultrasound examination have made it popular in our daily obstetrical practice. The review discusses the role of ultrasound in the most common life-threatening conditions during pregnancy.

Keywords: Life threatening, pregnancy, ultrasound

How to cite this article:
Kadasne AR, Mirghani HM. The role of ultrasound in life-threatening situations in pregnancy. J Emerg Trauma Shock 2011;4:508-10

How to cite this URL:
Kadasne AR, Mirghani HM. The role of ultrasound in life-threatening situations in pregnancy. J Emerg Trauma Shock [serial online] 2011 [cited 2019 Jun 24];4:508-10. Available from: http://www.onlinejets.org/text.asp?2011/4/4/508/86648



   Introduction Top


Vaginal bleeding associated with pelvic or abdominal pain are the most common complaints of pregnant women presenting to the emergency department. In addition to clinical history, physical examination, and laboratory data, ultrasound examination is essential for evaluating these patients. Over the last five decades, technology has provided ultrasound machines of high quality and resolution with the option of compact and mobile units. This has made it a useful tool for obstetrical assessment and diagnosis in emergencies.

Ultrasound has become an important tool in routine obstetrical care. This review limits itself to the role of ultrasound in some of the most common emergency conditions during pregnancy and the immediate postpartum period.

Ectopic pregnancy

Although maternal mortality rate attributed to ectopic pregnancy has dropped by about 50% in the past two decades in the developed country, it remains to be a common cause of morbidity and mortality in other parts of the world. [1] The major causes of death are excessive hemorrhage, shock, and renal failure. Therefore, ectopic pregnancy must be excluded in every woman in childbearing age. Physicians should be aware of the risk factors for ectopic pregnancy such as history of ectopic pregnancy, intrauterine contraceptive device, and pelvic inflammatory disease.

Pelvic pain is the most common symptom of an ectopic pregnancy. The classic triad of vaginal bleeding, adnexal tenderness, and an adnexal mass is present in less than 30% of ectopic pregnancies. The presence of a normal menstrual period should not exclude the possibility of an ectopic pregnancy.

Sonographic findings

A normal intrauterine gestational sac is eccentrically placed in the endometrial cavity and surrounded by a double decidual layer. This should not be confused with the pseudo sac that is formed due to the hormonal changes associated with an ectopic pregnancy and results in an endometrial fluid collection surrounded by a single decidual layer. The presence of a yolk sac confirms an intrauterine pregnancy [Figure 1].
Figure 1: An intrauterine gestational sac with a double ring sign. A yolk sac is seen within the gestational sac. The star marks the inner ring and the two triangles mark the outer ring. YS-yolk sac

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A complex adnexal mass of mixed echogenicity may be imaged following the rupture of an ectopic pregnancy. Occasionally, hemoperitoneum may be completely anechoic [Figure 2]. This should not be confused with the small amount of peritoneal fluid that may be present in normal pregnancy due to exudation from normal corpus luteum. Color doppler might be of help in the demonstration of the increased vascularity (ring of fire) around the ectopic pregnancy. In the absence of a detectable intrauterine gestation sac, transvaginal ultrasound should be used in conjunction with quantitative human chorionic gonadotropin (HCG) to increase the detection rate of unruptured ectopic pregnancy. [2]
Figure 2: Free fluid collection posterior to the uterus. The star marks the uterus and the triangle marks the free fluid collection

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Retained products of conception/incomplete miscarriage

Retained products of conception might result in severe vaginal hemorrhage or provide a nidus for uterine infection. Sonographic findings include endometrial thickening showing heterogeneous echogenic material and focal areas of hyperechogenicity that may represent retained products of conception. [3]

Placenta previa

Placenta previa is defined as implantation of the placenta in the lower uterine segment. A placenta that is inserted at a distance less than 2 cm from the internal cervical os is defined as a low-lying placenta. [4] The term "major placenta previa" indicates that the placenta is covering the internal cervical os [Figure 3]. The incidence of placenta previa is 0.5% at term. The neonatal mortality associated with placenta previa is four times that of other pregnancies. [5] Up to 15% of massive postpartum hemorrhage and maternal near-miss cases are caused by placenta previa and abruptio placentae. [6]
Figure 3: A posterior implanted placenta reaching and covering the internal cervical os. The arrow marks the placenta, the star marks the maternal bladder, and the triangle marks the cervix

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Multiparity, prior cesarean section and uterine curettage are the major predisposing factors for placenta previa . Because of the risk of provoking life-threatening hemorrhage, a digital vaginal examination is contraindicated until placenta previa is excluded. Transabdominal ultrasound might be a suitable approach when the placenta is inserted in the anterior wall. A mildly filled maternal bladder will help identify the lower uterine segment. However, transvaginal ultrasound is ideal when the placenta is inserted in the posterior uterine wall. [7]

Morbid adhesion of the placenta (accreta/increta/percreta)

Placenta accreta is defined as penetration of the chorionic villi into the superficial layer of the myometrium. The term increta is used when the chorionic villi penetrate the myometrium, while placenta percreta indicates that the placenta has penetrated through the uterine wall reaching peritoneal layer. The incidence of placenta accreta has increased steadily over the last few years from approximately 1/30,000 deliveries to 1/533 deliveries. This is attributed mainly to the increased rate of Cesarean sections. If encountered unexpectedly, morbid adhesion can lead to catastrophic blood loss. The antenatal diagnosis can help in reducing maternal morbidity and mortality, as the place and time of delivery as well as appropriate surgical approach can be planned in advance. [8]

The main sonographic features for morbid adhesion of the placenta are thinning from the retroplacental hypoechoic zone, presence of multiple placental lakes ("Swiss cheese" appearance), thinning of the uterine serosa-bladder wall complex, elevation of tissue beyond the uterine serosa, turbulent or complicated blood flow at the uteroplacental interface, and irregular blood flow underlying the maternal urinary bladder [Figure 4]. The last four features raise the suspicion of placenta percreta. Morbid adhesion of the placenta should be excluded in patients with anterior implanted placenta and history of repeated Cesarean section. [9]
Figure 4: A morbid adherent placenta. This is indicated by the increase blood flow

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Placental abruption

Placental abruption, or abruptio placentae, is defined as premature separation of a placenta implanted in the upper segment. External vaginal bleeding does not always occur; approximately 40% of cases have concealed retroplacental hemorrhage. The incidence of placental abruption is 1/100 births. [10] Pre-eclampsia, hypertension, maternal vascular disease, smoking, prior placental abruption, external trauma, etc are some of the major risk factors. The perinatal mortality rate associated with abruptio placentae is reported to be as high as 53%, and the near-miss maternal morbidity is as high as 22%. This is mainly due to the associated hypovolemic shock and coagulation failure. [11]

The sensitivity of an ultrasound examination in detecting placental abruption is as low as 25%. Therefore, physicians should rely on the clinical presentation for diagnosis. The main clinical features are vaginal bleeding associated with abdominal pain, tachycardia, drop in blood pressure, hard abdomen on palpation, and signs of fetal distress. Requesting an ultrasound examination in such patients is of little significance and might waste valuable time.


   Conclusions Top


Pregnancy might become complicated due to several conditions that are life threatening such as ectopic pregnancy, placenta previa, abruptio placentae, and morbid adhesion of the placenta. Ultrasound is an important and helpful tool in the investigation and diagnosis of such conditions. However, healthcare providers should be aware of its limitations. Therefore, as an adjunct diagnostic tool, it should not override their clinical judgment.

 
   References Top

1.Creanga AA, Shapiro-Mendoza CK, Bish CL, Zane S, Berg CJ, Callaghan WM. Trends in ectopic pregnancy mortality in the United States: 1980-2007. Obstet Gynecol 2011;117:837-43.  Back to cited text no. 1
[PUBMED]    
2.Morin L, Van den Hof MC; Society of Obstetricians and Gynaecologists of Canada. SOGC clinical practice guidelines. Ultrasound evaluation of first trimester pregnancy complications. Number 161, June 2005. Int J Gynaecol Obstet 2006;93:77-81.  Back to cited text no. 2
    
3.Abbasi S, Jamal A, Eslamian L, Marsousi V. Role of clinical and ultrasound findings in the diagnosis of retained products of conception. Ultrasound Obstet Gynecol 2008;32:704-7.  Back to cited text no. 3
[PUBMED]  [FULLTEXT]  
4.Hertzberg BS, Bowie JD, Carroll BA, Kliewer MA, Weber TM. Diagnosis of placenta previa during the third trimester : R0 ole of transperineal sonography. AJR Am J Roentgenol 1992;159:83-7.  Back to cited text no. 4
[PUBMED]  [FULLTEXT]  
5.Ananth CV, Smulian JC, Vintzileos AM. The effect of placenta previa on neonatal mortality : A0 population-based study in the United States, 1989 through 1997. Am J Obstet Gynecol 2003;188:1299-304.  Back to cited text no. 5
[PUBMED]  [FULLTEXT]  
6.Rizvi F, Mackey R, Barrett T, McKenna P, Geary M. Successful reduction of massive postpartum haemorrhage by use of guidelines and staff education. BJOG 2004;111:495-8.  Back to cited text no. 6
[PUBMED]  [FULLTEXT]  
7.Ghourab S. Third-trimester transvaginal ultrasonography in placenta previa : D0 oes the shape of the lower placental edge predict clinical outcome? Ultrasound Obstet Gynecol 2001;18:103-8.  Back to cited text no. 7
[PUBMED]  [FULLTEXT]  
8.Wong HS, Hutton J, Zuccollo J, Tait J, Pringle KC. The maternal outcome in placenta accreta : T0 he significance of antenatal diagnosis and non-separation of placenta at delivery. N Z Med J 2008;121:30-8.  Back to cited text no. 8
[PUBMED]    
9.Comstock CH. The antenatal diagnosis of placental attachment disorders. Curr Opin Obstet Gynecol 2011;23:117-22.  Back to cited text no. 9
[PUBMED]  [FULLTEXT]  
10.Tikkanen M. Placental abruption : E0 pidemiology, risk factors and consequences. Acta Obstet Gynecol Scand 2011;90:140-9.  Back to cited text no. 10
[PUBMED]  [FULLTEXT]  
11.Siddiqui SA, Tariq G, Soomro N, Sheikh A, Shabih-ul-Hasnain F, Memon KA. Perinatal outcome and near-miss morbidity between placenta previa versus abruptio placentae. J Coll Physicians Surg Pak 2011;21:79-83.  Back to cited text no. 11
[PUBMED]    

Top
Correspondence Address:
Hisham M Mirghani
Department of Obstetrics and Gynecology, Faculty of Medicine and Health Sciences, UAE University
United Arab Emirates
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0974-2700.86648

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    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4]

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