Assessment of Percentage Saturation of Hemoglobin with Oxygen in Arterial Blood of Pregnant Women

Abstract

Objective: Percentage saturation of hemoglobin with oxygen in arterial blood (SaO₂) was studied in pregnant women to evaluate the lung function status in pregnancy. Methods: This study was conducted in the department of physiology in Dhaka medical college during July 2004 to June 2005. For this purpose total 32 women with age ranged 25-35 years without any recent history of respiratory diseases were selected from Dhaka city. Eight (8) age matched apparently healthy women was taken as control and Twenty four (24) normal pregnant women without any complication were included in experimental group. All pregnant subjects were studied during first, second and third trimester. SaO₂ was determined by Easy Blood Gas Auto Analyzer. SaO₂ during different trimesters were compared with that of non pregnant and also among the trimesters. Statistical analysis was done by students unpaired t test. Result: Mean ±SD SaO₂ during first trimester (97.73%±0.92), second trimester (98.05%±0.54) and third trimester (98.40%±0.30) were progressively increasing and were significantly higher (p<0.05, p<0.001, p<0.001) than that of non pregnant women (96.71±0.63). But no statistically significant differences were observed among the trimesteric values. The present result indicates increased lung function in pregnant women associated with progressively increased oxygen saturation with trimester. Higher progesterone level is related to increased ventilation which is more marked in luteal phase of menstrual cycle. In pregnant women gradually rising progesterone level reaches its peak at the later part of pregnancy. Conclusion: Therefore it may be concluded from the present study that progressively increased SaO₂ might be related to hyperventilation induced by high progesterone level. Key words: Pregnant women, trimester, progesterone J Bangladesh Soc Physiol. 2006 Dec;(1):10-13.