Kathryn A. Houston and Sarah B. Wilson
History of present illness
A 28-year-old gravida 2, para 0 woman presents to the emer- gency room with a history of vaginal spotting for 2 days and some mild bilateral pelvic cramping. She has regular 28-day menstrual cycles and thefirst day of her last menstrual period was approximately 5 weeks ago. She was not using birth control and took a pregnancy test three days ago, which was positive. This pregnancy was not planned but is desired. She has a history of one prior first-trimester miscarriage. The remainder of her review of systems is negative. She has no significant past medical or surgical history. She has no known drug allergies. She does not smoke or drink. She works part time as a preschool teacher.
Physical examination
General appearance:Well-appearing woman in no acute distress
Vital signs:
Temperature: 37.4°C
Blood pressure: 125/70 mmHg Pulse: 80 beats/min
Respiratory rate: 19 breaths/min Oxygen saturation: 100% on room air Cardiovascular:Regular rate and rhythm Lungs:Clear to auscultation bilaterally
Abdomen:Soft, nontender, no rebound or guarding, no masses
Pelvic:
External genitalia: Normal in appearance Vagina: Scant dark red blood present
Cervix: No lesions, nulliparous appearing os, no active bleeding
Bimanual exam: Normal size anteverted uterus; no cervical motion, adnexal, or uterine tenderness Laboratory studies:
hCG: 943 mIU/mL Urinalysis: Negative Blood type: O positive
Imaging:A pelvic ultrasound was obtained (Fig. 55.1).The ultrasound showed a normal appearing uterus with an intrauterine echolucency suggestive of a gestational sac. The mean sac diameter measures 5 mm, which would be
consistent with an estimated gestational age of approximately 5 weeks. No yolk sac or embryo (fetal pole) is identified.
Normal appearing ovaries, no adnexal masses or freefluid
How would you manage this patient?
The patient was counseled regarding her clinicalfindings of an early pregnancy with uncertain viability given the context of her bleeding. It is also a pregnancy of undetermined location
Acute Care and Emergency Gynecology, ed. David Chelmow, Christine R. Isaacs and Ashley Carroll. Published by Cambridge University Press.
© Cambridge University Press 2015.
Fig. 55.1 Pelvic ultrasound.
given the nondiagnostic (although not unexpected) ultrasound findings. An ectopic gestation has not been ruled out given the absence of any defining embryonic growth, and as such the ultrasound echolucency may represent a pseudogestational or
“pseudosac”only. The patient’s early gestational age limits the ability to have a certain diagnosis and, thus, requires close follow-up and surveillance.
The patient was given precautions to return for any heavy vaginal bleeding or severe abdominal pain and was scheduled for a follow-up assessment in 48 hours, with a repeat human chorionic gonadotropin (hCG) level and ultrasound. Forty- eight hours later she continues to have light vaginal spotting.
hCG:1926 mIU/mL
Transvaginal ultrasound:SeeFig. 55.2. A normal appearing uterus with a gestational sac measuring 8 mm consistent with an estimated gestational age of 5.5 weeks. A yolk sac is visualized within the gestational sac. A fetal pole is not seen. Normal appearing ovaries, no adnexal masses or freefluid
The patient was counseled that she has a confirmed intrauter- ine pregnancy. Ectopic pregnancy has been ruled out with the presence of a yolk sac appearing within the intrauterine gestational sac. While she still has a risk of miscarriage in the context of the vaginal bleeding, the hCG level continues to rise as would be expected with a viable pregnancy. A follow-up office appointment was scheduled in a week with plans for a repeat ultrasound. Bleeding and pain precautions were reviewed with the patient.
Early pregnancy with vaginal spotting
Women often present in early pregnancy with symptoms of pelvic cramping, pain, or vaginal bleeding. While many of these pregnancies will progress normally, it is important to be able to diagnose both ectopic and nonviable pregnancies in the acute care setting. Evaluation of patients with early pregnancy bleeding or pain can be challenging. Patients are understandably eager to have a diagnosis and are often anxious
regarding their prognosis. A step-wise approach to evaluate the patient’s history, serum hCG levels, and transvaginal ultra- sounds is necessary to determine the correct diagnosis in early pregnancy. In addition, counseling and clinical follow-up are often an essential part of patient management.
The first step in evaluating any condition of early preg- nancy is taking a patient history and trying to identify/
calculate the gestational age from the patient’s last menstrual period (LMP). This history may unfortunately be limited as menstrual cycles may vary in length and regularity, and patients are not always certain as to when their LMP occurred.
To further help determine the best estimated gestational age, any recent history of birth control use or timing of coitus may provide additional clues.
The clinical history should also reference the presence and duration of vaginal bleeding and abdominal/pelvic pain.
Ectopic pregnancies commonly present with either bleeding or pain and account for 1–2% of all pregnancies and 6% of maternal deaths in the United States. Intra-abdominal hemor- rhage from rupture of the ectopic pregnancy is the cause of death in over 90% of these cases [1]. The goal is to diagnose ectopic pregnancies before tubal rupture in order to prevent morbidity/mortality. Half of women in whom ectopic preg- nancy is diagnosed however, have no identifiable risk factors or initial physical findings. Risk factors include a history of pelvic inflammatory disease, prior tubal sterilization, prior ectopic pregnancy, pelvic surgery, assisted reproductive tech- nologies, and smoking [2]. If ectopic pregnancy cannot be ruled out during the initial evaluation by demonstrating embryonic growth within the uterus (as in the case of our patient’sfirst ultrasound), the patient must have close follow- up and an understanding of her circumstances until the diag- nosis of an ectopic pregnancy can be excluded.
Finally, the clinical history often includes a discussion regarding the patient’s intentions and/or desire for the preg- nancy as many patients will have strong feelings that help guide in counseling and further management.
Laboratory assessments with hCG levels are also important in guiding the practitioner as they indicate what developmental milestones should be seen on transvaginal ultrasound. hCG levels, however, are not especially useful in determining actual gestational age as they can vary widely during thefirst trimes- ter and with multiple gestations. When the hCG measures greater than or equal to 1500–2000 mIU/mL (called the“dis- criminatory zone”), a fetal pole should be seen on transvaginal ultrasound of a singleton gestation. Failure to visualize a fetal pole on transvaginal ultrasound with an hCG of greater than 2000 mIU/mL should arise suspicion of an ectopic or other nonviable pregnancy. hCG levels should increase by a min- imum of 53% over a 48-hour interval in a viable singleton pregnancy [3]. Failure to accomplish this increase is also highly suspicious of a nonviable or ectopic pregnancy. Unfor- tunately, hCG levels are highly variable in ectopic pregnancies and should not be used alone to confirm the diagnosis.
Repeated hCG assessments over time to follow trends, in
Fig. 55.2 Transvaginal ultrasound.
Case 55: Early pregnancy with vaginal spotting
conjunction with repeated ultrasound evaluations are required to make a confident diagnosis.
In addition to hCG assessments, a patient’s blood type, specifically the Rh D antigen status, should be confirmed by a type and screen. Whether to administer anti-D immune globulin to prevent Rh alloimmunization to a patient with threatened abortion and a live embryo or fetus at or before 12 weeks of gestation is controversial, and no evidence-based recommendation can be made. Rh D alloimmunization attrib- utable to threatened abortion prior to 12 weeks’ gestation is exceedingly rare. The decision to administer anti-D immune globulin when comparing the overall benefit with the cost of its widespread use has caused many physicians to not routinely administer this in these circumstances [4].
Transvaginal ultrasound is the best imaging modality to diagnose early pregnancy location and confirm viability. Prior to eight weeks’ gestation, transvaginal ultrasound is usually necessary to visualize uterine contents as opposed to an abdominal ultrasound. At four to five weeks’gestational age, a gestational sac can usually be seen on a transvaginal ultra- sound and its location should be documented. The presence of an intrauterinefluid collectionwithouta yolk sac or fetal pole cannot be assumed to be a gestational sac, as it could represent a “pseudosac” [5]. A pseudosac is a small fluid collection located within the uterine cavity appearing in the context of and ectopic pregnancy.
Between five and six weeks’ gestation, a yolk sac should typically be seen within the gestational sac. The presence of an intrauterine gestational sac with a yolk sac confirms an intra- uterine pregnancy, as was the case in the second ultrasound of this patient. Except in the very rare instance of heterotopic pregnancy, an ectopic has been ruled out.
Between 6 and 7 weeks’ gestation, or with a mean gesta- tional sac diameter of 20 mm or greater, a fetal pole (embryo)
should become visible. Visualization of a gestational sac, yolk sac, and embryo with cardiac motion verifies a viable intra- uterine pregnancy. If a fetal pole is present, it must be at least 5–7 mm without cardiac motion to diagnose a nonviable preg- nancy [5,6]. If the embryo measures less than 5 mm in length, a subsequent scan at a later date will be necessary to assess the presence or absence of cardiac activity.
In this particular case the patient has a confirmed intra- uterine pregnancy only after the second ultrasound revealed an intrauterine gestational sac with a yolk sac. The appropriate rise in hCG levels over 48 hours is an encouraging clinical sign and viability will be confirmed when a future scan dem- onstrates an embryo with cardiac motion.
Key teaching points
Clinical history to assess last menstrual period/calculate estimated gestational age, human chorionic gonadotropin (hCG) levels, and pelvic ultrasound are the critical components for evaluation of an early pregnancy.
When the hCG level is greater than 1500–2000 mIU/mL (the“discriminatory zone”) an intrauterine gestation should be visible on transvaginal ultrasound. Ultrasound evaluation done prior to this may be nondiagnostic.
The presence of an intrauterine gestational sac with a yolk sac on ultrasound confirms an intrauterine pregnancy and rules out the possibility of an ectopic pregnancy.
A yolk sac should been seen betweenfive and six weeks’
gestation.
hCG levels should increase by greater than 53% over 48-hour period in a normal, viable, singleton pregnancy.
Serial hCG monitoring and ultrasound evaluation may be necessary to assess early pregnancies presenting with bleeding and uncertain viability or location.
References
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