Embryonic growth discordance

Embryonic growth discordance is a term given to a twin growth discordance occurring during the early embryonic period. It is principally manifested by a discrepancy in crown rump length. It can be a relative common finding in early twin pregnancies with the mean discrepancy according to one study at around 3-4%. It is considered independent of the chorionicity of the twins 5.


Many associations have been described which include

Practical points

  • for milder degrees of discrepancy some authors suggest the CRL of the smaller fetus being a more accurate estimate of the actual gestational age. 
  • in the absence of aneuploidy or structural fetal abnormality, a recent study has suggested CRL discordance having a poor predictive value for adverse perinatal outcome in both monochorionic and dichorionic twin pregnancies; the CRL discordance is not recommended to identify twin pregnancies at high risk of adverse perinatal outcome 4.
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Article information

rID: 39706
System: Obstetrics
Synonyms or Alternate Spellings:
  • CRL discrepanacy in early pregnancy
  • CRL discordance in early pregnancy
  • Embryonic growth discrepancy
  • CRL discrepancy in early twin pregnancy

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