Pocket ObGyn – Hydrops Fetalis
See Abbreviations
Definition and Epidemiology
- Accum of fluid in 2 of the following 5 extravascular compartments: Heart (pericardial effusion), lungs (pleural effusion), abd (ascites), subcutaneous tissue best seen around fetal skull (edema), amnion (polyhydramnios)
- Immune Hydrops: Rh isoimmunization
RhD– Mom w/ RhD+ fetus has 16% chance of undergoing isoimmunization
¯ to 2% w/ postpartum anti-D immune globulin administration
¯ to 0.1% w/ additional administration in the 3rd trimester (Transfus Med Rev 1988:2:129)
6/1000 live births undergo Rh isoimmunization
2nd Preg more affected than 1st (1st usually mildly affected, if affected at all, as 1st Ig produced is IgM – DOES NOT cross placenta)
- Nonimmune Hydrops: All other causes
Genetic (aneuploidy,Turner syn, trisomies), CV (structural, arrhythmias, vascular abnormalities), hematologic (a-thal), respiratory (pulm hypoplasia), infectious (CMV, syphilis, Parvovirus, Rubella)
1/1500–1/3800 births affected
Etiology
- Immune: Unclear, possibly from fetal anemia/hypoxia leading to heart failure
Mom RhD–, fetus RhD+ ® Mom makes antibodies ® cross placenta ® antibodies bind to fetal bld ® hemolysis of fetal bld ® release of bilirubin & fetal anemia ® fetal cardiac failure & damaged myocardium ® fluid accum ® hydrops fetalis
- Nonimmune: Dependent upon the underlying d/o
Clinical Manifestation
- US findings can include enlarged liver/spleen/placenta/heart, ascites
- Fetal HR tracings: Sinusoidal pattern indicative of fetal anemia
- Mirror syn: Mother gets edema that mimics the hydropic fetus
Physical Exam
- Mother may appear edematous if experiencing mirror syn
- Infant can range from hyperbilirubinemic to pale, limp, edematous
Diagnostic Workup/Studies
- Immune: All women have Rh(D) typing & Ab screening at 1st prenatal visit ® if antibodies present indirect Coombs test detects Ab titer
Titer <1:32
Rpt titer every 4 w
After 24 w gest, rpt titer every 2 w
If remains <32 deliver at term vs. if ³32 proceed w/ w/u below Titer ³1:32
Test father’s Ag & genotype
Homozygous: MCA Dopplers q1–2w starting at 18–24 w gest
Heterozygous: Perform amniocentesis for fetal DNA
RhD+: Proceed w/ MCA Dopplers
RhD–: Deliver fetus at term, no further testing
• Nonimmune:
Detailed personal (inquire about infectious contacts) & FHx Perform detailed US & consider fetal ECHO
Obtain MCA Dopplers to assess fetal anemia Offer amniocentesis (karyotype, TORCH panel)
Obtain mat bld (anemia w/u, type & screen, serologies for CMV, parvovirus B19, toxoplasmosis, syphilis)
Subsequent Workup
- MCA Dopplers
Peak MCA velocity >1.5 MoM ® check fetal HCT via PUBS ® transfuse fetus if HCT <30%
Peak MCA velocity £1.5 MoM ® continue MCA Dopplers q1–2w Nomogram to monit MCA Doppler results is valid until 35 w gest
Treatment and Medications
- Immune: PUBS, intrauterine fetal bld xfusion when needed, Phenobarb 30 mg PO TID to mother prior to deliv if received multi PUBs and need for delivery
- Nonimmune: Prog dependent upon etiology; worse prog when diagnosed earlier in gest & w/ pleural effusions or polyhydramnios
CV issues: ~40% of nonimmune hydrops
Fetal arrhythmias (eg, SVT) can be treated w/ mat rate controlling meds Mortality rate 50–98% (approaches 100% if <30 w gest w/ pleural effusions) Often may require supportive care or offering termination of Preg Continue to monit MCA Dopplers as above if dx is anemia