Relation between frequency of uterine contractions and human fetal cerebral oxygen saturation studied during labour by near infrared spectroscopy.
OBJECTIVE
To investigate the effect of the frequency of uterine contractions on fetal cerebral oxygenation, using near infrared spectroscopy.


METHODS
An observational study relating changes in the fetal cerebral concentrations of oxyhaemoglobin and deoxyhaemoglobin, measured from the start of one contraction to that of the next, to the time interval between contraction peaks observed by external tocography.


METHODS
A teaching hospital obstetric and neonatal unit.


METHODS
Ten term fetuses during labour.


RESULTS
Changes in cerebral oxyhaemoglobin concentration were positively, and in deoxyhaemoglobin negatively, correlated with the time interval between contractions (P < 0.001). A mean contraction interval of 2.3 min was found below which the concentration of oxyhaemoglobin usually fell and that of deoxyhaemoglobin rose, indicating a fall in cerebral haemoglobin saturation. Conversely, longer contraction intervals were associated with findings indicative of a rise in cerebral haemoglobin saturation.


CONCLUSIONS
Short contraction intervals (< 2.3 min) were associated with a decrease, and longer contraction intervals with an increase in fetal cerebral oxygen saturation. Contractions occurring repeatedly at intervals less than 2.3 min are likely to result in progressive cerebral desaturation.
Peebles
D M
DM
Department of Obstetrics and Gynaecology, University College London Medical School, UK.
Spencer
J A
JA
Edwards
A D
AD
Wyatt
J S
JS
Reynolds
E O
EO
Cope
M
M
Delpy
D T
DT
D001923:Brain Chemistry; D036861:Delivery, Obstetric; D005260:Female; D005333:Fetus / Q000502:physiology*; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D010100:Oxygen / Q000097:blood*; D011247:Pregnancy; D013055:Spectrophotometry, Infrared; D013997:Time Factors; D014590:Uterine Contraction / Q000502:physiology*
D006454:Hemoglobins; C100003:deoxyhemoglobin; D010100:Oxygen