August 22, 2012

Pregnant woman with recurrent vaginal bleeding

A pregnant woman complains of recurrent vaginal bleeding. Her fetus is small for dates at 32 weeks gestation. The next most appropriate step is:

a) Angiography of the iliac vessels
b) Ultrasound localisation of placenta
c) Doppler cord blood flow studies
d) CTG
e) Maternal ECG
f) Hgb estimation
g) Rhesus status
h) Speculum exam
i) Kleihauser test
j) Coagulation profile






ANSWER
The correct answer is B


Explanation
When a patient in labor presents with vaginal bleeding, the physician must consider several possible causes. Placenta previa should be ruled out when a patient has copious vaginal bleeding. The classic presentation of placenta previa is painless vaginal bleeding and a soft, nontender uterus. If readily available, ultrasonography should be performed immediately, since placenta previa can be quickly and accurately diagnosed by ultrasound examination. When ultrasonography is not available, gentle speculum examination may be considered, as long as the bleeding is not brisk. This examination should be performed with a "double set-up" in case immediate cesarean section is required.

Transabdominal, transperineal and transvaginal sonography (TVS) have been used to localize the placenta with variable success rates. Sonographic diagnosis of placenta previa has an excellent record of accuracy and safety. Vaginal ultrasound is the most accurate method for localizing and diagnosing placenta previa because it can utilize higher frequencies of ultrasound and provide a better resolution of the lower edge of the placenta.

The patient who complains of abdominal pain between uterine contractions or a tender uterus must be presumed to have abruptio placentae. Since ultrasound examination has a high false-negative rate in diagnosing abruption, this obstetric complication is diagnosed clinically. In one prospective study, 78 percent of patients with abruptio placentae presented with vaginal bleeding, 66 percent with uterine or back pain, 60 percent with fetal distress and only 17 percent with uterine contractions or hypertonus.

The management of abruptio placentae is primarily supportive and entails both aggressive hydration and monitoring of maternal and fetal well-being. Coagulation studies should be performed, and fibrinogen and D dimers or fibrin degradation products should be measured to screen for disseminated intravascular coagulation. Packed red blood cells should be typed and held. If the fetus appears viable but compromised, urgent cesarean delivery should be considered.

The presentation of uterine rupture may be similar to that of abruptio placentae. Signs and symptoms include vaginal bleeding, uterine pain and a nonreassuring fetal tracing. Uterine rupture occurs in 0.2 to 0.8 percent of vaginal birth after cesarean (VBAC) deliveries. In general, however, a trial of labor after previous low transverse uterine incision is safe and usually successful.

Uterine rupture also occurs more commonly in cocaine abusers or patients who have been given high doses of oxytocin or prostaglandins. On palpation, the uterine fundus may feel boggy and tender, and it may seem to be expanding. Intrauterine pressure monitoring has not proved helpful in diagnosing uterine rupture. Treatment includes aggressive resuscitation and urgent surgical delivery.

A history of abrupt onset of vaginal bleeding that began with rupture of membranes suggests vasa previa, especially when bleeding is accompanied by decreased fetal movement and a nonreassuring fetal tracing. Urgent cesarean section is generally performed. The differential diagnosis of antepartum vaginal bleeding also includes normal "bloody show" and mucopurulent cervicitis. Vasa previa should be suspected when bloody show is excessive.

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