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Clinical Trial
. 2012;7(7):e39154.
doi: 10.1371/journal.pone.0039154. Epub 2012 Jul 16.

Risk factors for preterm birth in an international prospective cohort of nulliparous women

Gustaaf Albert Dekker  1 , Shalem Y Lee, Robyn A North, Lesley M McCowan, Nigel A B Simpson, Claire T Roberts
Affiliations
Clinical Trial

Risk factors for preterm birth in an international prospective cohort of nulliparous women

Gustaaf Albert Dekker et al. PLoS One. 2012.

Abstract

Objectives: To identify risk factors for spontaneous preterm birth (birth <37 weeks gestation) with intact membranes (SPTB-IM) and SPTB after prelabour rupture of the membranes (SPTB-PPROM) for nulliparous pregnant women.

Design: Prospective international multicentre cohort.

Participants: 3234 healthy nulliparous women with a singleton pregnancy, follow up was complete in 3184 of participants (98.5%).

Results: Of the 3184 women, 156 (4.9%) had their pregnancy complicated by SPTB; 96 (3.0%) and 60 (1.9%) in the SPTB-IM and SPTB-PPROM categories, respectively. Independent risk factors for SPTB-IM were shorter cervical length, abnormal uterine Doppler flow, use of marijuana pre-pregnancy, lack of overall feeling of well being, being of Caucasian ethnicity, having a mother with diabetes and/or a history of preeclampsia, and a family history of low birth weight babies. Independent risk factors for SPTB-PPROM were shorter cervical length, short stature, participant's not being the first born in the family, longer time to conceive, not waking up at night, hormonal fertility treatment (excluding clomiphene), mild hypertension, family history of recurrent gestational diabetes, and maternal family history of any miscarriage (risk reduction). Low BMI (<20) nearly doubled the risk for SPTB-PPROM (odds ratio 2.64; 95% CI 1.07-6.51). The area under the receiver operating characteristics curve (AUC), after internal validation, was 0.69 for SPTB-IM and 0.79 for SPTB-PPROM.

Conclusion: The ability to predict PTB in healthy nulliparous women using clinical characteristics is modest. The dissimilarity of risk factors for SPTB-IM compared with SPTB-PPROM indicates different pathophysiological pathways underlie these distinct phenotypes.

Trial registration: ACTR.org.au ACTRN12607000551493.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. Participants recruited and study population.
Figure 2
Figure 2. Receiver-operating characteristic curve for SPTB-IM.
Figure 3
Figure 3. Receiver-operating characteristic curve for SPTB-PPROM.
See this image and copyright information in PMC

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