The origin of fetal sterols in second-trimester amniotic fluid: endogenous synthesis or maternal-fetal transport?
OBJECTIVE
Cholesterol is crucial for fetal development. To gain more insight into the origin of the fetal cholesterol pool in early human pregnancy, we determined cholesterol and its precursors in the amniotic fluid of uncomplicated, singleton human pregnancies.


METHODS
Total sterols were characterized by gas chromatography-mass spectrometry in the second-trimester amniotic fluid of 126 healthy fetuses from week 15 until week 22.


RESULTS
The markers of cholesterol biosynthesis, lanosterol, dihydrolanosterol, and lathosterol, were present in low levels until the 19th week of gestation, after which their levels increased strongly. β-sitosterol, a marker for maternal-fetal cholesterol transport, was detectable in the amniotic fluid. The total cholesterol levels increased slightly between weeks 15 and 22.


CONCLUSIONS
Our results support the hypothesis that during early life the fetus depends on maternal cholesterol supply because endogenous synthesis is relatively low. Therefore, maternal cholesterol can play a crucial role in fetal development.
Eurocat Registration Northern Netherlands and Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
Maria E
ME
Baardman
Jan Jaap H M
JJ
Erwich
Rolf M F
RM
Berger
Robert M W
RM
Hofstra
Wilhelmina S
WS
Kerstjens-Frederikse
Dieter
D
Lütjohann
Torsten
T
Plösch
D000653:Amniotic Fluid / Q000737:chemistry*; D005260:Female; D006801:Humans; D008431:Maternal-Fetal Exchange; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D012189:Retrospective Studies; D013261:Sterols / Q000032:analysis* / Q000096:biosynthesis / Q000378:metabolism*
D013261:Sterols