o_1977r8vv9vk1ts2ms0kd8pksa.pdf

a Chapter 13 Cerebral and Umbilical Doppler in the Prediction of Fetal Outcome 191
Fig. 13.14. Chronic nicotine
administration. Variations of
the fetal cerebral resistance index
(CRI), on lamb fetuses, during
gestation (140 days). On
the ªcontrol-placeboº group
the CRI decreases progressively
from gestation day 80 until the
end of the gestation, but not
on the nicotine group submitted
to repeated daily maternal
injections of nicotine
since gestation day 30. During
the same period the C/U ratio
remains constant in the control
group; however, it increases by
25% in the nicotine group (reduction
of cerebral perfusion
in the nicotine group)
sis that if fetal hypoxia develops in ªnicotine fetuses,º
the capability of the brain vessels to adapt by vasodilation
is reduced because of the ªvasoconstrictiveº effect
of nicotine and the deleterious effects of the drug
on the growth and the maturation of the brain structures.
Cerebral Flow and Long-Term Cocaine
Treatment (Animal Model)
Uteroplacental flow and fetal cerebral flow were assessed
by Doppler ultrasonography in pregnant ewes
treated daily with cocaine beginning on gestational
day 60 (Fig. 13.15). Fetal weight and fetal pO 2 were
measured at delivery. The study groups received
70 mg (n=7) or 140 mg (n=7) of cocaine intramuscularly
and the control group (n=7) was given an intramuscular
placebo. The maternal heart rate and the
uterine RI (vascular resistance index) were always
significantly higher (p