Vol. 274, Issue 5, R1492-R1495, May 1998
Electrical potential difference between exocelomic fluid and
maternal blood in early pregnancy
Stuart
Ward1,
Eric
Jauniaux2,
Claire
Shannon3,
Charles
Rodeck2,
Robert
Boyd4, and
Colin
Sibley5
Departments of 1 Obstetrics and
Gynaecology and Reproductive Health Care,
5 Child Health and School of
Biological Sciences, University of Manchester, St. Mary's Hospital,
Manchester M13 OJH; 2 Department
of Obstetrics and Gynaecology, University College London, London WC1E
6HX; 3 Department of Anaesthetics,
Guy's and St. Thomas's National Health Service Trust, London SE1
9RT; and 4 St. George's Hospital
Medical School, London SW17 ORE, United Kingdom
The forces that drive transfer of
solutes between maternal blood and
embryo in early human pregnancy are poorly understood. The aim of this
study was to determine whether there is an electrical potential
difference (PD) between maternal blood and the
exocelomic cavity and between maternal blood and the
amniotic cavity in the normal human conceptus at or before 10 wk of
pregnancy. We measured PD between a saline-filled catheter in a forearm
vein of women undergoing termination of pregnancy for psychological
reasons in the first trimester and a second saline-filled catheter in the exocelomic cavity or amniotic cavity of their conceptus. The mean
(±SE) maternal blood/exocelomic cavity PD in eight
women was 8.7 ± 1.0 mV and the mean maternal blood/amniotic cavity
PD in four of the women was 6.7 ± 1.3 mV, embryo side negative for both sets of measurement. These data show that there is a PD between maternal and embryonic extracellular fluid in the first trimester that
will directly influence exchange of ions between the two compartments.
placenta; embryo; fetus; ions; amniotic fluid
