Am J Perinatol 2024; 41(S 01): e275-e281
DOI: 10.1055/a-1877-9798
Original Article

Confirmatory Middle Cerebral Artery Doppler Testing in Alloimmunized Patients with Suspected Fetal Anemia

Douglas S. Richards
1   Division of Maternal Fetal Medicine, Intermountain Healthcare, Salt Lake City, Utah
2   Division of Maternal Fetal Medicine, University of Utah Health, Salt Lake City, Utah
,
Ashley E. Benson
1   Division of Maternal Fetal Medicine, Intermountain Healthcare, Salt Lake City, Utah
2   Division of Maternal Fetal Medicine, University of Utah Health, Salt Lake City, Utah
,
Brett D. Einerson
1   Division of Maternal Fetal Medicine, Intermountain Healthcare, Salt Lake City, Utah
2   Division of Maternal Fetal Medicine, University of Utah Health, Salt Lake City, Utah
› Author Affiliations
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Abstract

Objective This article aimed to evaluate pregnancy outcomes when a plan to perform fetal blood sampling (FBS) or delivery was based solely on the first abnormal middle cerebral artery peak velocity (MCA-PV) measurement compared with making a plan after a confirmatory test on a subsequent day.

Study Design We performed a descriptive study of pregnancy outcomes including all patients in a single healthcare system with maternal red cell alloimmunization undergoing ultrasound between 2005 and 2017 who had at least one MCA-PV>1.5 multiples of the median (MoM). We excluded patients with any sign of hydrops prior to the index visit or abnormal MCA-PV at>35 weeks. The first exam with a MCA-PV>1.5 MoM was deemed the index visit.

Results Fifty patients were identified. Twenty-one patients underwent intervention (FBS or delivery) based on the first abnormal MCA-PV. Of those, 9 had moderate or severe anemia (positive predictive value [PPV]: 43%), while 12 had mild or no anemia. The other 29 patients underwent a confirmatory MCA test between 2 and 8 days later. Of these, 13 patients had an abnormal confirmatory test and 11 of these underwent FBS and 7 had moderate or severe anemia (PPV: 54%). Sixteen patients undergoing confirmatory MCA Doppler had a normal test on repeat and did not undergo FBS. Of those, none developed moderate or severe anemia.

Conclusion A substantial number of patients (55%) had normal MCA-PV testing on repeat, allowing avoidance of invasive testing. Deferring FBS until the abnormal MCA-PV was confirmed was not associated with undetected moderate or severe anemia.

Key Points

  • False-positive results from MCA-PV Doppler prediction of fetal anemia are common.

  • Repeat noninvasive testing is normal in many patients with suspected fetal anemia.

  • Invasive fetal testing can often be safely avoided by performing a confirmatory Doppler exam ination.



Publication History

Received: 07 April 2022

Accepted: 03 June 2022

Accepted Manuscript online:
16 June 2022

Article published online:
02 September 2022

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