TOG 2023 April
Hydrops Fetalis
- abnormal fluid accumulation within at least two fetal compartments
- pericardial effusion, pleural effusions, ascites and skin oedema
NIHF >>>
- Maternal RBC-AB have been excluded
- Accounts for >90% of all HF cases.
- Affect 1 in 2000 pregnancies
- 60% of perinatal mortality, with significant perinatal morbidity and maternal
implications due to polyhydramnios, malpresentation and preterm birth. - small but significant risk of maternal mirror syndrome, a pre-eclampsia-like condition
Mechanisms for NIHF - disordered fluid homeostasis à fluid accumulation within fetal body cavities
- loss of natural equilibrium between the intravascular & interstitial spaces
- Fetal interstitial space compliance is 10 times greater than in adults
- Fetal lymphatic flow is approximately 5 times higher than in adults
- even small increases in fetal venous pressure will reduce lymphatic flow rate
NIHF in 1st trimester
Causes and investigations
- maternal RBC-AB does not occur until the midtrimester, therefore fetal anaemia is
not usually observed until 18 weeks - >2/3 of NIHF cases presenting <14 weeks’ POG à due to chromosomal
abnormalities
Counselling
- NIHF < 14 weeks à 2/3 of pregnancies ended in MC or IUD
- 4/10 babies NND
- “There is a substantial risk that if the child was born it would suffer from such
physical or mental abnormalities as to be seriously handicapped”
NIHF in the 2nd & 3rd trimesters
Causes and investigations
- fetal medicine emergency
- may be >>>
o immune anaemic
o non-immune anaemic
o non-immune non-anaemic - All cases of HF should be excluded the anaemic status. à
o R/V maternal, paternal & fetal RBC-AB status.
o Anemia àMCA-PSV >1.5 MOM - Fetal anaemia à immediately communicate with a fetal medicine unit able to
provide in-utero transfusion. - Chromosomal abnormality à 20% of cases à monogenic disorders
- Fetal infections à 20% of cases
- Cardiovascular à 10% of causes
Counselling and management
2nd Trimester
- 50% >> IUD
- 20% >> NND
T3 >>> - 1/6 à IUD
- ¼ à NND
TOP >> - genetic abnormalities, CVS conditions & overall poor outcomes
- MDT discussion
Fetal therapy
Fetal therapy considered >>
- cause for NIHF is known
- woman is committed to the pregnancy
- informed prospective consent à procedural risks, benefits and alternatives;
- specialist MDT determines that a favourable outcome is achievable
- trained fetal therapy team are able to competently perform the procedure.
Primary pleural effusion à - thoracocentesis à sent for virology, protein concentration & cell count à exudate
or transudate
Thoracic-amniotic shunt >> - pleural effusion is primary or secondary to a fetal lung lesion
- aneuploidy has been excluded
Maternal complications
polyhydramnios
o Precipitates preterm birth
o Placental abruption
o Maternal discomfort
o Prostaglandin inhibitors such as indomethacin
Maternal mirror syndrome (or Ballantyne syndrome) à
- rare maternal complication of NIHF
o placentomegaly
o new onset oedema
o hypertension
o proteinuria indistinguishable from pre-eclampsia
o adverse systemic sequelae - Pre-eclampsia à haemoconcentration from reduced intravascular volume
- MMS à anaemia & haemodilution secondary to increased intravascular volume.
- pathophysiology is poorly understood
- hydropic placenta and subsequent endothelial dysfunction and trophoblastic injury
Joint working
MDT
- fetal-medicine subspecialists
- Midwives
- clinical geneticists
- genomic scientists
- neonatologists
- perinatal pathologists
- Local and tertiary fetal medicine teams
- referred urgently
- investigations and/or fetal therapy
- 2. Clinical genetics
- NIHF is typically genetic
- referral to a prenatal genetic clinic
- pre- and post-test counselling
3. Neonatology and palliative care
- optimise perinatal outcome à minimum of 34weeks
- antenatal corticosteroids for fetal lung maturity
Conclusions - second trimester onward is an emergency and the priority is to quickly identify the
anaemic fetus and provide rescue transfusion - NIHF responsible for > 90% of HF
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