The effect of uterine contractions on fetal oxygen saturation.
OBJECTIVE
To find out what happens to fetal arteriolar oxygen saturation during a uterine contraction.


METHODS
Prospective observational study.


METHODS
Labour ward, St James's University Hospital, Leeds.


METHODS
Eighteen women in normal labour monitored with a fetal scalp surface pulse oximetry sensor, an intrauterine pressure catheter, and a head to cervix force transducer.


METHODS
The effect of intrauterine pressure and head to cervix force on fetal arteriolar oxygen saturation was examined using time series analysis and a regression model of 159 contractions.


METHODS
Fetal oxygen saturation during a contraction.


RESULTS
The average oxygen saturation drops after a contraction. The greatest drop in oxygen saturation is reached 92 s after the peak of a contraction and takes approximately 1 min 30 s to recover (P = 0.036).


CONCLUSIONS
Uterine contractions during normal labour affect fetal oxygen saturation.
McNamara
H
H
Leeds General Infirmary, Academic Unit of Obstetrics and Gynaecology, UK.
Johnson
N
N
D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D006801:Humans; D010092:Oximetry; D010100:Oxygen / Q000097:blood*; D011247:Pregnancy; D011312:Pressure; D011446:Prospective Studies; D014590:Uterine Contraction / Q000502:physiology*
D010100:Oxygen