Today we’re bringing back Dr. Erin Cleary one more time before she transitions to her new role as an MFM fellow at the Ohio State University! Dr. Cleary today talks with us on early pregnancy of unknown location - a common problem in the office or the emergency department/triage.
Women presenting to the ED with first trimester bleeding, pain, or both, have had a demonstrated prevalence rate of ectopic pregnancy up to 18% in some studies. Ruptured ectopic is a leading cause of pregnancy-related mortality in the first trimester, accounting for 2.7% of pregnancy-related deaths overall in 2011-2013. Proper identification and management of early, unlocated pregnancy is life-saving!
Dr. Cleary was kind enough to put together her high points from this episode for our blog post today:
Any patient with an unlocated pregnancy should be considered to have a potential ectopic pregnancy.
Women with prior ectopic, regardless of method of treatment, are at risk for ectopic in a subsequent pregnancy (three- to eightfold higher compared with other pregnant women).
If pregnancy is present while IUD is in place, risk of ectopic is 1 in 2 pregnancies for the levonorgestrel IUD and 1 in 16 pregnancies for the copper IUD.
Women with a history of PID have an approximately threefold increased risk of ectopic pregnancy
Pelvic exam. THIS MUST BE DONE.
The threshold for a positive qualitative β-hcg test is 20-50 milli-int units, depending on test. For quantitative serum tests, the threshold is 5-10 milli-int units, and 1-2 milli-int units, for ultrasensitive tests.
The β-hcg concentration doubles every 29 to 53 hours during the first 30 days after implantation of a viable, intrauterine pregnancy.
When ectopic pregnancy is on the differential, a qualitative test is not sufficient. A serum quantitative value is essential to:
1. Interpret imaging (“discriminatory zone”)
2. Have a baseline in the event the β-hcg must be trended
The Discriminatory Zone
Definition: A concept that there is a quantitative β-hcg level above which the landmarks of a normal intrauterine pregnancy (yolk sac and embryo) should be visible on ultrasound.
Therefore, the absence of a gestational sac when β-hcg level is above the DZ is strongly suggestive of nonviable pregnancy, with 50-70% being ectopic.
Pelvic ultrasound is the gold standard first line imaging modality in early pregnancy and for evaluation of suspected ectopic pregnancy
Imaging results will fall into 1 of 5 main categories
IUP with normal adnexa. Normal pregnancy!
IUP with abnormal adnexa. Although rare, must evaluate for heterotopic pregnancy, or presence of both an intra and extra-uterine pregnancy.
No IUP, extra-uterine mass with YS/FP. Confirms ectopic pregnancy.
No IUP, adnexal mass without YS/FP. Suspicious for ectopic pregnancy
No IUP, normal adnexa. Differential includes normal but early IUP, failed IUP, or unidentified ectopic.
A patient with a confirmed ectopic requires evaluation and counseling by an OBGYN to evaluate candidacy for medical or surgical evaluation.
Expectant management: serial quantitative β-hcg level assessment ~q 48 hours, only for stable patients.
Scenario A: The β-hcg level rises appropriately (doubles approximately every 2 days).
Scenario B: The β-hcg level falls precipitously.
Scenario C: The β-hcg level neither rises appropriately nor drops precipitously. Now we should be MORE concerned about ectopic pregnancy, but abnormal IUP is also on the differential.
Repeat pelvic imaging is very helpful
Every patient who is stable and an appropriate candidate to trend β-hcg levels will eventually declare herself, with either a located IUP, a failed IUP/SAB, or a confirmed or presumed ectopic pregnancy.
We will cover ectopics for surgical and medical management in a future episode, so stay tuned!