Fetal Outcomes After POCUS for Vaginal Bleeding in Pregnancy

Fetal outcomes byte


Fetal outcomes following emergency department point-of-care ultrasound for vaginal bleeding in early pregnancy

Canadian Family Physician July 2016 - Pubmed Link


Take Home Points

1. In this population, if positive fetal cardiac activity seen on POCUS, only 5% chance of pregnancy loss.

2. If only IUP seen on POCUS, 22% chance of pregnancy loss.

3. Reported accuracies of POCUS for IUP and FCA cannot be taken at face value due to limitations.


Background

Vaginal bleeding during early pregnancy is a commonly encountered scenario. The first objective is always to exclude ectopic pregnancy as the cause for symptoms since this can be a life threatening diagnosis. In most cases, this can be done by confirming an intrauterine pregnancy (IUP). However, once you have determined there is an IUP, what next? In most cases, you would now tell the patient they have a “threatened abortion”, meaning they are at risk for having a spontaneous abortion (aka a miscarriage). These also can present with bleeding and occur in 20% of all pregnancies, most commonly (80%) in the first trimester. How do we counsel the patient with bleeding in early pregnancy with regard to their chances of having a good outcome? This study takes a look to see what happens to these patients after having confirmed an IUP on a point-of-care ultrasound.


Question

What are the 20 and 40 week fetal outcomes following ED point-of-care ultrasound documentation of fetal cardiac activity (FCA) and intrauterine pregnancy in women less than 20 weeks pregnant with vaginal bleeding?

How accurate are point-of-care studies compared to radiologist-interpreted transvaginal ultrasound?


Population

Single center ED, Canada

Inclusion

  • Presenting to ED with vaginal bleeding

  • Older than 17

  • Less than 20 weeks gestation (based on last menstrual period date)

Exclusion

  • Confirmed ectopic

  • Missed abortion on previous imaging

  • Not assessed by CEUS-IP provider (see below)


Who did the scans?

Canadian Emergency Ultrasound Society - Independent Practitioner (CEUS-IP) certified emergency department provider

22 EM physicians and 1 nurse practitioner


Design

Prospective observational cohort study

Primary outcome defined as prevalence of spontaneous abortion or pregnancy loss by 40 weeks gestation following ED POCUS documentation of FCA and IUP at less than 20 weeks gestation.

Secondary outcome was test characteristics for accuracy of transabdominal POCUS compared to comprehensive transvaginal ultrasounds.


Intervention

Study participants underwent focused transabdominal POCUS

Follow up transvaginal ultrasound in radiology department - same day or within 72 hours of discharge

Contacted by telephone at 20 and 40 weeks (±2 weeks) to determine fetal viability. If could not be contacted, chart review performed.


The Scan

Curvilinear probe (for transabdominal), endoluminal probe (for transvaginal)

IUP defined as yolk sac or fetal pole visible

FCA not defined but presumably when they could see definitive cardiac motion.


IUP Ultrasound from 1 Minute Ultrasound

More comprehensive but longer video about POCUS for pregnancy


Results

85 patients enrolled

Total of 8 patients lost to follow up at various points in the study (see below for individual N’s used in analysis)

Most patients included were >30 years old

Mean GA 9.5 weeks

Majority (74.1%) of follow up scans ≤ 24 hours after ED visit

43 (50.6%) had FCA and 54 (63.5%) had IUP


Primary Outcomes
+ IUP

20 weeks (n = 52) - 9 (17.3%) experienced pregnancy loss

40 weeks (n = 50) - 11 (22.0%) experienced pregnancy loss

No IUP

40 weeks (n = 31) - 29 (93.5%) experienced pregnancy loss


+ FCA

20 weeks (n = 42) - no pregnancy loss

40 weeks (n = 40) - 5% pregnancy loss (1 termination, 1 fetal loss at 22 weeks)

No FCA

40 weeks (n = 41) - 38 (92.7%) had pregnancy loss


Secondary Outcomes

ED POCUS Compared to Comprehensive Radiologist Interpreted Ultrasound


For FCA

  • 88.9% sensitive, 100% specific

  • Kappa = 0.87

For IUP

  • 96% sensitive, 93.1% specific

  • Kappa = 0.89

2 False positives for IUP - ED POCUS had IUP, comprehensive study WITHIN 72 HOURS documented SAB but noted gestational sac and intrauterine contents

2 False negatives for IUP - not seen on ED POCUS, seen on comprehensive


Other Findings

All patients with serum Bhcg <1000 IU/L reported nonviable pregnancy by 20 weeks GA

Three patients had ectopic pregnancies - none had IUP documented on ED POCUS. All were visualized on radiologist interpreted ultrasound


Limitations

Single center - the population may be different than yours depending on access to primary care and other factors.

With 8 lost to follow up, this is below the sample size calculation performed (required 81 patients)

Diagnostic accuracy likely low for two reasons

  • Apples and oranges - comparing ED transabdominal to radiologist transvaginal? Not very fair.

  • A lot can happen in 72 hours, 2 false positives could have been accurate POCUS studies with progression to SAH by the time they got comprehensive studies

Rate of pregnancy loss after FCA much lower than prior studies (11.1%, 14.8%). Possibly explained by including some second trimester pregnancies?

Did not take into account the age of the pregnancies. For example, no FCA at 4 weeks is not the same chance of loss of pregnancy as no FCA at 19 weeks.


Take Home Points

1. In this population, if positive fetal cardiac activity seen on POCUS, only 5% chance of pregnancy loss.

2. If only IUP seen on POCUS, 22% chance of pregnancy loss.

3. Reported accuracies of POCUS for IUP and FCA cannot be taken at face value due to limitations.


Our score

3 Probes


Published on 02/27/17 01:00 AM
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