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Fetal monitoring with pulse oximetry
Author(s) -
JOHNSON NICHOLAS,
JOHNSON VALERIE A.,
FISHER JOHN,
JOBBINGS BRIAN,
BANNISTER JEFFREY,
LILFORD RICHARD J.
Publication year - 1991
Publication title -
bjog: an international journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.157
H-Index - 164
eISSN - 1471-0528
pISSN - 1470-0328
DOI - 10.1111/j.1471-0528.1991.tb10308.x
Subject(s) - fetus , medicine , pulse oximetry , oxygen saturation , scalp , cervical dilatation , anesthesia , oxygen , surgery , chemistry , pregnancy , cervix , biology , genetics , organic chemistry , cancer
Summary. Continuous fetal monitoring was achieved with a fetal scalp pulse oximetry sensor in 86 labours. The average recorded fetal oxygen saturation in early labour (cervical dilatation < 5 cm) was 68% (SD 13%). At the end of labour (cervical dilatation ≥ 9 cm) the recorded mean oxygen saturation was 58% (SD 17%). The largest range of readings during a single labour was 81%‐11% but this drop was associated with cord compression. The average SD during 1 h of normal labour was 10%. A second group of 40 fetuses was monitored during induction of labour before and after elective amniotomy. Oxygen saturation did not appear to change after amniotomy (mean change −0.4%, SD 1.2%) and there was no difference between mean antenatal or early intrapartum readings. We excluded the amniochorionic membranes as a possible source of data corruption by measuring their in vitro absorption spectra and confirming that they do not preferentially absorb light of either 660 or 940 nm wavelength. Non‐invasive pulse oximetry can be used to monitor the fetus before and during labour.