Acute effect of cigarette smoking on placental circulation - a study by carbon-monoxide measurement and Doppler assessment.
OBJECTIVE
Carbon-monoxide (CO) decreases placental vascular impedance. We assessed the consequences of smoking-induced temporary maternal CO-increase on fetal and placental circulation.


METHODS
In a prospective study twenty-nine smoking pregnant women and their fetuses were evaluated. We determined the changes in maternal blood CO levels after smoking, and the concomitant changes in maternal and fetal circulation. Changes in fetal heart rate, uterine artery (UTA), middle cerebral artery (MCA), and descending aorta (DA) flow were measured by Doppler velocimetry. Changes in maternal CO level and umbilical flow value were assessed by paired t-test. The correlation between CO level and placental flow was assessed by partial correlation test.


RESULTS
CO level increased (mean +/-SD 1.7 +/- 0.065% vs. 2.36 +/- 0.89, p<0.0001). Nicotine-related maternal circulatory parameters changed significantly, but uterine flow values remained unchanged. Fetal heart rate increased, while flow in MCA and DA showed no change. CO-dependent umbilical artery impedance remained unchanged (Pulsatility Index: 0.956 +/- 0.18 vs. 0.948 +/- 0.21). Partial correlation between CO level and umbilical arterial impedance showed no significance (r:-0.324).


CONCLUSIONS
Despite significant CO elevation, the mainly CO-regulated placental flow remained unchanged.
Ovári
László
L
University of Debrecen, Department of Obstetrics and Gynecology, Medical and Health Sciences Center H-4012 Debrecen Hungary. ovarirobert@yahoo.com
Aranyosi
J
J
Balla
Gy
G
D001783:Blood Flow Velocity / Q000187:drug effects* / Q000502:physiology; D001794:Blood Pressure / Q000187:drug effects; D002248:Carbon Monoxide / Q000097:blood*; D005260:Female; D005333:Fetus / Q000098:blood supply; D006801:Humans; D017078:Laser-Doppler Flowmetry; D018811:Maternal Exposure; D021041:Placental Circulation / Q000187:drug effects*; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D011446:Prospective Studies; D012016:Reference Values; D012039:Regional Blood Flow; D012907:Smoking; D018709:Statistics, Nonparametric
D002248:Carbon Monoxide