Hyponatremia and Myometrium Contractility. An Invitro Study

Hyponatremia during labour has been associated with prolonged labour, and increased incidence of instrumental delivery and emergency caesarean section. Sodium influx in myometral cells are involved in contractility,and and influence of hyponatraemia on contractility can be suspected.

Biopsies will be obtained from pregnant women undergoing planned caesarean section at term. The biopsies will divided into 3 strips that will be stored overnight in chilled NaCl 0.9%. The following morning each strip will be mounted isometrically with one end fixed to a holder and the other end to a force transducer. One strip will be maintained in a solution containing 140mmol/L Na,acting as control, whereas the other two strips will be placed in fluids with diminishing Na concentration, from 140 mmol/L, to 130 mmol/L and 120 mmol/L. Contractility will be measured with force transducers and a polygraph