Abnormal uterine bleeding can be due to, in the pregnant patient, a complication of pregnancy. In the non-pregnant patient, abnormal uterine bleeding can be due to anovulation (either physiologic or pathologic) or to structural causes.
So the first task of the physician in any patient with abnormal uterine bleeding (and equally to any female patient with pelvic pain) is to determine pregnancy status with a pregnancy test.
Abnormal Uterine Bleeding in the First Trimester
In this post I consider abnormal uterine bleeding (or/and) pelvic pain in the pregnant patient.
For an excellent discussion of the outcome of first trimester bleeding see Dr. Thomas Joseph Lydon’s lecture “Vaginal Bleeding in the First Trimester“. (2)
The American College of Emergency Physicians has an outstanding clinical practice guideline addressing this problem. (1) What follows is from that resource.
“Emergency physicians frequently evaluate and manage patients with abdominal pain and/or vaginal bleeding in the first trimester of pregnancy (also referred to here as “early pregnancy”). Their primary concern in this group of patients is to identify ectopic pregnancy. The prevalence of ectopic pregnancy in symptomatic emergency department (ED) patients is as high as 13% in some series, which is much higher than the prevalence in the general population.2, 3 With wide availability of bedside ultrasound in academic EDs and increasing access in community settings, more providers are now routinely using ultrasound in their evaluation of these patients.4”
“The term bedside ultrasound is used here to refer to pelvic ultrasounds that are performed in the ED by the emergency clinician, rather than in the radiology department. With the term pelvic ultrasound, the use of a transvaginal approach is implied unless transabdominal images have identified an intrauterine pregnancy.”
It is critical to note that, as the document states above and as used in the guideline, the term “pelvic ultrasound” means Pelvic and Transvaginal Ultrasound (see article for details as to when a transvaginal ultrasound may not be needed).
Critical Questions
1. Should the emergency physician obtain a pelvic ultrasound in a clinically stable pregnant patient who presents to the ED with abdominal pain and/or vaginal bleeding and a β-hCG level below a discriminatory threshold?
Patient Management Recommendations:
Perform or obtain a pelvic ultrasound for symptomatic pregnant patients with a β-hCG level below any discriminatory threshold. (Level C recommendation)
What ACEP says is that there is no quantitative Beta-hCG level below which one can safely defer pelvic and transvaginal ultrasound.
2. In patients who have an indeterminate transvaginal ultrasound, what is the diagnostic utility of β-hCG for predicting possible ectopic pregnancy?
Patient Management Recommendations
Do not use the β-hCG value to exclude the diagnosis of ectopic pregnancy in patients who have an indeterminate ultrasound. (Level B recommendation)
Obtain specialty consultation or arrange close outpatient follow-up for all patients with an indeterminate pelvic ultrasound. (Level C recommendation)
“A majority of patients who have a pelvic ultrasound during their ED evaluation for symptomatic early pregnancy will receive a diagnosis of an intrauterine pregnancy or an abnormal pregnancy (eg, ectopic pregnancy, fetal demise, or molar pregnancy). A significant minority, however, will have an indeterminate, or nondiagnostic, ultrasound; most ED literature reports an indeterminate study rate of 20% to 30%.”
No level of quatative Beta-hCG rules out ectopic pregnancy in an indeterminant ultrasound.
Another point made by Dr. Kevin M. Klaur at a recent conference: In the context of a positive pregnancy test and no intrauterine pregnancy, assume that free fluid on the ultrasound represents ruptured ectopic pregnancy until proven otherwise. (2)
Because there was no new data on the topic, ACEP carried forward the following recommendation from 2003:
Is the administration of anti-D immunoglobin indicated among Rh-negative women during the first trimester of pregnancy with threatened abortion, complete abortion, ectopic pregnancy, or minor abdominal trauma?
Administer 50 micrograms of anti-D immunoglobulin to Rh-negative women in all cases of documented loss of an established first trimester pregnancy. (Level B recommendation)
Consider administration of anti-D immunoglobulin in cases of minor trauma in Rh-negative patients.
(1) American College of Emergency Physicians 2012: Clinical Policy: Critical Issues in the Initial Evaluation and Management of Patients Presenting to the Emergency Department in Early Pregnancy
(2) Audio Digest Emergency Medicine 30:16 2013, Obstetric Emergencies
