Acid-base and hematologic values at blood sampling in the evaluation of trisomic fetuses: a case-control study.
OBJECTIVE
To investigate whether nonhydropic trisomic fetuses display specific alterations of acid-base and/or hematologic values.


METHODS
Acid-base and hematologic variables were analyzed in 28 trisomic fetuses (12 with trisomy 21 and 16 with trisomy 18) and 28 chromosomally normal controls matched for gestational age and fetal size undergoing fetal blood sampling at 18-36 weeks' gestation.


RESULTS
There were no differences between the groups in pH, oxygen pressure, carbon dioxide pressure, and base excess. Compared with matched controls, hematocrit, hemoglobin, and red blood cell counts were significantly higher in fetuses with trisomy 21 and significantly lower in those with trisomy 18. All other hematologic variables were similar in trisomic fetuses and their controls.


CONCLUSIONS
Growth retardation in trisomic fetuses is associated with decreased oxygen supply, as it is in chromosomally normal growth-retarded fetuses. The higher perinatal mortality that occurs with trisomies 21 and 18 is not explained by more pronounced hypoxemia for a given degree of growth retardation. There is no specific association of acid-base and hematologic values that is diagnostic of chromosomal abnormality at fetal blood sampling.
Extermann
P
P
Institute of Obstetrics and Gynaecology, Royal Postgraduate Medical School, Queen Charlotte's and Chelsea Hospital, London, United Kingdom.
Nicolini
U
U
Rodeck
C H
CH
D000137:Acid-Base Imbalance / Q000175:diagnosis* / Q000453:epidemiology; D016022:Case-Control Studies; D002887:Chromosomes, Human, Pair 18; D004314:Down Syndrome / Q000175:diagnosis* / Q000453:epidemiology; D005260:Female; D005312:Fetal Blood; D005315:Fetal Diseases / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D006801:Humans; D011247:Pregnancy; D014314:Trisomy