Progesterone for prevention of recurrent preterm birth: impact of gestational age at previous delivery.
OBJECTIVE
Preterm birth occurs in 1 of 8 pregnancies and may result in significant morbidity and mortality. 17-alpha hydroxyprogesterone caproate (17-OHP caproate) has been found to be efficacious in reducing the risk of subsequent preterm delivery in women who have had a previous spontaneous preterm birth (sPTB). This analysis was undertaken to evaluate if 17-OHP caproate therapy works preferentially depending on the gestational age at previous spontaneous delivery. We hypothesized that treatment with 17-OHP caproate is more effective in prolonging pregnancy depending on the gestational age of the earliest previous preterm birth (20-27.9, 28-33.9 vs 34-36.9 weeks).


METHODS
This was a secondary analysis of 459 women with a previous sPTB enrolled in a randomized controlled trial evaluating 17-OHP caproate versus placebo. Effectiveness of 17-OHP caproate for pregnancy prolongation was evaluated based on gestational age at earliest previous delivery according to clinically relevant groupings (20-27.9, 28-33.9, and 34-36.9 weeks). Statistical analysis included the chi-square, Fisher exact, and Kruskal-Wallis tests, logistic regression, and survival analysis using proportional hazards.


RESULTS
Gestational age at earliest previous delivery was similar between women treated with 17-OHP caproate or placebo (P = .1). Women with earliest delivery at 20 to 27.9 weeks and at 28 to 33.9 weeks delivered at significantly more advanced gestational age if treated with 17-OHP caproate than with placebo (median 37.3 vs 35.4 weeks, P = .046 and 38.0 vs 36.7 weeks, P = .004, respectively) and were less likely to deliver <37 weeks (42% vs 63%, P = .026 and 34% vs 56%, P = .005, respectively). Those with earliest delivery at 34 to 36.9 weeks were not significantly different between 17-OHP caproate or control.


CONCLUSIONS
17-OHP caproate therapy given to prevent recurrent PTB is associated with a prolongation of pregnancy overall, and especially for women with a previous spontaneous PTB at <34 weeks.
Spong
Catherine Y
CY
National Institute of Child Health and Human Development, Bethesda, MD, USA.
Meis
Paul J
PJ
Thom
Elizabeth A
EA
Sibai
Baha
B
Dombrowski
Mitchell P
MP
Moawad
Atef H
AH
Hauth
John C
JC
Iams
Jay D
JD
Varner
Michael W
MW
Caritis
Steve N
SN
O'Sullivan
Mary J
MJ
Miodovnik
Menachem
M
Leveno
Kenneth J
KJ
Conway
Deborah
D
Wapner
Ronald J
RJ
Carpenter
Marshall
M
Mercer
Brian
B
Ramin
Susan M
SM
Thorp
John M
JM
Peaceman
Alan M
AM
Gabbe
Steven
S
D019326:17-alpha-Hydroxyprogesterone / Q000627:therapeutic use*; D005260:Female; D005865:Gestational Age; D006801:Humans; D016015:Logistic Models; D011247:Pregnancy; D047928:Premature Birth / Q000517:prevention & control*; D016016:Proportional Hazards Models; D012008:Recurrence
D019326:17-alpha-Hydroxyprogesterone