EFFECT OF PREGNANCY ON MATERNAL OXYGEN-SATURATION VALUES - USE OF REFLECTANCE PULSE OXIMETRY DURING PREGNANCY

Our objective was to evaluate the usefulness of pulse oximetry monitor ing in a large population of pregnant patients. We designed our study to measure pulse oximetry saturation in a cross section of 952 obstetr ic inpatients and outpatients. A group of 366 patients identified as n ormal were compared with abnormal subgroups. A subgroup of 64 patients with Saturation measurements less than 96% were further evaluated. Ou r results indicated that oxygen saturation values did not change appre ciably during the course of pregnancy in normal patients. Hypoxemia (s aturation measurement less than 96%) was associated with smoking, and hypoxemia with preterm labor occurred more frequently in patients who smoked. Obesity and magnesium sulfate use appeared to be synergistic i n the presence of hypoxemia. We concluded that the routine use of puls e oximetry during pregnancy may not be justified. Smoking, obesity, an d magnesium sulfate use have some effect on oximetry in pregnant patie nts.