Differentials
Preterm labor
SIGNS / SYMPTOMS
Preterm labor and placental abruption may coexist. Careful clinical assessment is essential to differentiate between preterm labor and abruption (10% of idiopathic preterm labor is due to placental abruption).
Bleeding is light rather than moderate-to-heavy.
INVESTIGATIONS
Ultrasound may be helpful. Positive findings may be diagnostic of abruption. Preterm labor generally is associated with a normal ultrasound and generally does not result in fetal heart rate abnormalities or DIC.
Placenta previa
SIGNS / SYMPTOMS
Classically presents with painless vaginal bleeding; however, painful contractions may accompany this.
Bleeding if placenta previa has been excluded by ultrasound should be considered to be due to abruption until proven otherwise.
INVESTIGATIONS
A sonogram, including a search for ultrasound signs of abruption and sonographic assessment of the area over the cervix, may be useful in distinguishing between the two conditions. In placenta previa, the placenta will be seen overlying the internal cervical os.
Occasionally, transvaginal sonography may be used to examine the lower uterine segment in order to exclude placenta previa.
Chorioamnionitis
SIGNS / SYMPTOMS
Bleeding is uncommon.
Fever may be present.
INVESTIGATIONS
Careful clinical assessment is required; however, WBC count may be elevated.
Acute appendicitis
SIGNS / SYMPTOMS
No vaginal bleeding.
Pain is typically located in either the RLQ or periumbilical region.
Frequently associated with a loss of appetite, vomiting, and fever.
INVESTIGATIONS
Elevated WBC count is typical.
CT scan or an ultrasound may show evidence of appendicitis.
Acute pyelonephritis
SIGNS / SYMPTOMS
No vaginal bleeding.
Frequently associated with dysuria, fever, rigors, flank pain, and costovertebral angle tenderness.
INVESTIGATIONS
Elevated WBC count.
Urine microscopy typically shows evidence of white cells and bacteria on Gram stain.
Urine dipstick testing will be positive for leukocyte esterase and nitrites.
Positive urine culture is confirmatory.
Urinary tract infection
SIGNS / SYMPTOMS
No vaginal bleeding.
Typically presents with dysuria and suprapubic pain.
INVESTIGATIONS
Urine dipstick testing will be positive for leukocyte esterase and nitrites.
Urine microscopy will reveal WBC and bacteria.
Culture identifies causative organisms.
Degeneration of uterine fibroids
SIGNS / SYMPTOMS
No vaginal bleeding.
Fibroids may occasionally be palpable; however, they may also be associated with abruption and preterm labor, so caution should be exercised to ensure that women with fibroids are not having an abruption.
Point tenderness on palpation over the location of the fibroid, particularly if there is no bleeding, will make abruption unlikely.
INVESTIGATIONS
Fibroids can generally be identified on sonography.
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