PHYSIOLOGY

Pain relief from uterine contractions and cervical dilation in stage 1 of labor
involves thoracic nerve roots, T10 to T12. Pain relief from perineal distention in
stage 2 of labor involves sacral nerve roots, S2 to S4.

Pregnancy   predisposes to  hypoxia because of  decreased   functional  residual

capacity.

Placental   transfer    of  medications exposes the fetus   to  lipid-soluble   anionic

substances.

Antacids    should  be  given   prophylactically    because of  delayed gastric

emptying    time    in  pregnancy.

Uterus  should  be  laterally   displaced   to  avoid   inferior    vena    cava    compression

in  the supine  position.