Bethany and Molly discuss how to monitor an Alloimmunized pregnancy. This is the first step to treating a sensitized pregnancy. Monitoring the antibody titer can indicate when you need MCA Scans, and intrauterine blood transfusions to keep your baby healthy.
Episode themes:
- How babies at risk for HDFN are monitored
- Titers (purpose and frequency)
- MCA Scans and MoM values (purpose and frequency)
- Specific MCA Scan tips
- What’s next after a high MCA scan
- Fetal outcomes and survival rates
Terminology used in this episode:
- Antibody Titer: A measure of antibodies in the mom’s blood, indicates threat to a baby who is affected. Antigen negative babies do not need titer monitoring.
- Critical Titer: A titer level of 16 (or 4 for Kell) that indicates a need for in utero medical treatments. Remember, once you hit critical levels in a pregnancy you are considered always critical for each subsequent pregnancy and should start MCA scans at 15 weeks in that and each subsequent pregnancy.
- MCA Scan: (Middle Cerebral Artery Doppler Scan) Special ultrasound often only used after a critical titer is detected. Scans the blood flow in the middle cerebral artery of the fetus.
- MoM: (Multiple of the Median score) the final measurement of an MCA scan divided by gestational age of fetus. Scores of 1 are ideal, scores of 1.5 or higher indicate moderate to severe anemia and a need for intervention.
- Hematocrit: a score detected during a cordocentesis (blood drawn from the cord) to determine the red blood cell volume in the blood. The normal hematocrit range for infants 0-6 months is 37.4 - 55.9% for females, and 43.4 - 56.1% for males. A fetal hematocrit of less than 30% is considered anemia. Cordocentesis tests can start at 15 weeks.
Anti-E Pregnancy Study: Moran P, Robson SC, Reid MM. Anti‐E in pregnancy. BJOG: An International Journal of Obstetrics & Gynaecology. 2000 Nov;107(11):1436-8. LINK
Survival rates for fetuses receiving IUTs: Lee L, Nasser J. Doppler ultrasound assessment of fetal anaemia in an alloimmunised pregnancy. Australasian Journal of Ultrasound in Medicine. 2010 Nov;13(4):24. LINK
Allo Hope Terminology Library https://allohopefoundation.org/library/terminology/
For more on tests during pregnancy, see our prenatal testing guide at https://allohopefoundation.org/library/prenatal-testing/
Research for this episode provided by Bethany Weathersby and Molly Sherwood of the Allo Hope Foundation. Find more information at https://allohopefoundation.org.
The Allo Podcast is produced and edited by https://www.mediaclub.co.
