Progesterone for prevention of preterm
birth
Most studies of progesterone in prevention of
preterm birth concerned 2 target groups: 1) pregnant
women with previous preterm birth and 2) the women
with short cervix during mid-trimester. Most studies
used either intramuscular or vaginal progesterone for
the prevention of preterm birth. Only few studies with
small number of cases used oral progesterone. So, we
do not include oral progesterone in this review.
Effect of progesterone in the women at risk
for preterm birth (Table 1.)
da Fonseca (2003) published the first randomized,
placebo controlled, double-blind study of progesterone
and preterm birth(17) using either transvaginal, 100 mg
of natural progesterone or placebo in pregnant women
at risk for preterm birth during 24-34 weeks of gestation.
The incidence of preterm birth was significantly lower
in the progesterone group (28.5% VS 13.8%). Study by
Meis (2003) showed that intramuscular 17 OHP-C
significantly reduced preterm birth. Infants of women
treated with 17 OHP-C had significantly lower rates of
necrotizing enterocolitis, intravascular hemorrhage, and
need for supplemental oxygen(18). The gestational age
at delivery and the reduction of spontaneous preterm
birth before 37 weeks were greatest in women with
history of previous preterm birth before 34 weeks’
gestation(19). In contrast, O’Brien (2007) found that
progesterone vaginal gel could not reduce preterm birth
rate, neonatal morbidity and mortality(20).
Subsequent meta-analysis concluded that
progesterone supplementation reduced the rate of
preterm birth while the reduction in perinatal or neonatal
morbidity and mortality were not consistently
demonstrated