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Am J Perinatol 2014; 31(12): 1023-1030
DOI: 10.1055/s-0034-1370342
Original Article
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Fetal Fibronectin versus Cervical Length as Predictors of Preterm Birth in Twin Pregnancy with or without 17-Hydroxyprogesterone Caproate

C. Andrew Combs
1   The Center for Research, Education, and Quality, Mednax, Inc., Sunrise, Florida
2   Obstetrix Medical Group, San Jose, California
,
Thomas J. Garite
1   The Center for Research, Education, and Quality, Mednax, Inc., Sunrise, Florida
3   Department of Obstetrics and Gynecology, University of California, Irvine, California
,
Kimberly Maurel
1   The Center for Research, Education, and Quality, Mednax, Inc., Sunrise, Florida
,
Anita Das
4   Axistat, Inc., San Francisco, California
,
for the Obstetrix Collaborative Research Network › Author Affiliations
Further Information

Publication History

16 September 2013

02 January 2014

Publication Date:
24 February 2014 (online)

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Abstract

Objective The objective of this study was to compare cervicovaginal fetal fibronectin (FFN) versus transvaginal sonographic cervical length as predictors of preterm birth in twin pregnancy and to test whether 17-hydroxyprogesterone caproate (17OHPc) modifies the predictive value of FFN.

Study Design Secondary analysis of a randomized trial of 17OHPc versus placebo in dichorionic-diamniotic twins, analyzing the subset with screening FFN (N = 198) and/or cervical length (N = 214) at 24 to 26 weeks of gestation.

Results Positive FFN was found in 7%, cervical length ≤ 25 mm in 8%, and both positive FFN and cervical length ≤ 25 mm in 3%. Birth < 32, < 34, and < 37 weeks occurred in 8, 30, and 67%, respectively. In logistic regression analysis controlling for FFN, cervical length, prior preterm birth, and treatment group, positive FFN was significantly associated with birth < 30 and < 32 weeks (odds ratio 55.0 [95% confidence interval 5.2–582], 18.1 [3.3–99], respectively, p < 0.001 for both) but cervical length ≤ 25 mm was not (odds ratio 0.1 [0.002–1.6], 0.6 [0.1–4.3]).

Conclusion Positive FFN was stronger than cervical length ≤ 25 mm in predicting early preterm birth in twins, regardless of 17OHPc use. Treatment with 17OHPc did not appear to alter the predictive value of FFN.

Keywords

fetal fibronectin - cervical length - twin pregnancy - 17-hydroxyprogesterone caproate - preterm birth prediction