Objective: To determine the effect of gestational age and cervical dilation
on pregnancy continuation in women with idiopathic preterm labor who were
treated with parenteral tocolysis. Method: A total of 950 women with single
ton gestations, intact membranes and preterm labor treated with tocolysis p
rior to 34 weeks' gestation were retrospectively studied. These women were
identified from the March of Dimes prematurity prevention program database.
For analysis, women were categorized into five gestational age groups and
three cervical dilation groups. The primary outcomes measured were the perc
entage of women who remained undelivered at 48 h and at 14 days post-initia
tion of therapy. Result: Overall, 82% of women remained undelivered after 4
8 h and 65% remained undelivered at 14 days. As cervical dilation advanced,
the number of women remaining undelivered at 48 h and 14 days significantl
y decreased. However, even at greater than or equal to 4 cm, 52% of women r
emained undelivered at 48 h. If the cervix was dilated < 2 cm, gestational
age did not influence the number of days gained prior to delivery. However,
if the cervix was dilated 2 2 cm, women at < 25 weeks' gestation were more
likely to deliver compared to women at the same dilation but with more adv
anced gestational ages. Conclusion: Overall, 82% of women in preterm labor
and 52% of those presenting with greater than or equal to 4-cm cervical dil
ation, delivered after 48 h. Therefore there appears to be ample opportunit
y for most women in preterm labor with intact membranes, even those at adva
nced dilations, to receive a complete course of corticosteroid therapy. (C)
1999 International Federation of Gynecology and Obstetrics.