Oxygen saturation in the supine hypotensive syndrome

Area of Science:

• Obstetrics and Gynecology
• Maternal-Fetal Medicine
• Cardiovascular Physiology in Pregnancy

Background:

• The supine position can trigger supine hypotensive syndrome in pregnant individuals.
• Understanding positional effects on vital signs is crucial for third-trimester maternal care.

Purpose of the Study:

• To evaluate positional variations in pulse, blood pressure, and oxygen saturation in pregnant women during nonstress testing.
• To assess the incidence and severity of supine hypotensive syndrome in the third trimester.

Main Methods:

• Continuous noninvasive monitoring of pulse, blood pressure, and oxygen saturation.
• Evaluation of 42 pregnant women in their third trimester and 10 nonpregnant controls.
• Assessment of supine hypotensive syndrome criteria (blood pressure decrease, pulse increase).

Main Results:

• 14.3% of pregnant women developed supine hypotensive syndrome, with 21.4% meeting at least one criterion.
• Nonpregnant women showed blood pressure elevation, not hypotension, in the supine position.
• No significant oxygen desaturation occurred in pregnant women, though transient minor desaturation was noted in some hypotensive cases.

Conclusions:

• A significant percentage of third-trimester pregnant patients experience supine hypotension.
• Supine hypotensive syndrome is prevalent, but severe oxygen desaturation is uncommon.
• Noninvasive monitoring effectively captures positional hemodynamic changes in pregnancy.