Biochemical composition of amniotic fluid in pregnancies complicated with twin-twin transfusion syndrome.
OBJECTIVE
To compare the electrolyte composition of pregnancies complicated with twin-twin transfusion syndrome (TTTS) with that of physiologic pregnancies.


METHODS
Amniotic fluid samples from 16 pregnancies were studied. Specimens were obtained from recipient sacs in 10 pregnancies undergoing fetoscopy for severe midtrimester TTTS. Additionally, 6 amniotic fluid samples were obtained transcervically from legal second-trimester pregnancy terminations. The concentrations of sodium, potassium, chloride, bicarbonate, calcium, glucose, osmolality, pH, total protein content and albumin were determined in each sample.


RESULTS
The mean gestational age at sampling was 20.2 weeks (range 17.2-27.1) in the TTTS group and 18.4 (range 16.0-22.0) in the control group (p = NS). We found significant lower levels of albumin (0.22 +/- 0.04 vs. 0.39 +/- 0.11, p = 0.01) and total protein (0.19 +/- 0.08 vs. 0.51 +/- 0.17, p < 0.001) and higher levels of bicarbonate (16.90 +/- 1.45 vs. 14.50 +/- 2.17, p = 0.02) in amniotic fluid samples taken from recipient sacs of TTTS pregnancies.


CONCLUSIONS
Amniotic fluid from the receptor in severe midtrimester TTTS differs significantly from control amniotic fluid samples in bicarbonate concentration, total protein content and albumin concentration. These findings may help to understand the pathophysiology of TTTS and to optimise therapeutic modalities.
Adama van Scheltema
P N
PN
Fetal Diagnosis and Therapy Unit, Department of Obstetrics, Leiden University Medical Centre, Leiden, The Netherlands.
In't Anker
P S
PS
Vereecken
A
A
Vandenbussche
F P H A
FP
Kanhai
H H H
HH
Devlieger
R
R
D000418:Albumins / Q000032:analysis; D000653:Amniotic Fluid / Q000737:chemistry*; D001639:Bicarbonates / Q000032:analysis; D016022:Case-Control Studies; D004573:Electrolytes / Q000032:analysis; D005260:Female; D005330:Fetofetal Transfusion / Q000378:metabolism*; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy
D000418:Albumins; D001639:Bicarbonates; D004573:Electrolytes