1. Volume 382, Issue 9901, Pages 1341-1349 (October 2013)
Cervical pessaries for prevention of preterm birth in women with a multiple pregnancy (ProTWIN): a multicentre, open-label randomised controlled trial 
Dr Sophie Liem, MD, Ewoud Schuit, PhD, Maud Hegeman, MD, Joke Bais, PhD, Karin de Boer, PhD, Kitty Bloemenkamp, PhD, Jozien Brons, PhD, Hans Duvekot, PhD, Bas Nij Bijvank, MD, Maureen Franssen, PhD, Ingrid Gaugler, PhD, Irene de Graaf, PhD, Martijn Oudijk, PhD, Dimitri Papatsonis, PhD, Paula Pernet, MD, Martina Porath, PhD, Liesbeth Scheepers, PhD, Marko Sikkema, PhD, Jan Sporken, PhD, Harry Visser, PhD, Wim van Wijngaarden, PhD, Mallory Woiski, MD, Mariëlle van Pampus, PhD, Prof Ben Willem Mol, PhD, Dick Bekedam, PhD 
The Lancet 
Volume 382, Issue 9901, Pages (October 2013)
DOI: /S (13)
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2. Figure 1
Trial profile
The Lancet  , DOI: ( /S (13) )
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3. Figure 2
Kaplan Meier curves of proportion of continued pregnancies in (A) all women, (B) women with a cervical length of less than 38 mm, and (C) women with a cervical length of at least 38 mm
All curves censored at 37 weeks' gestation. 38 mm is the 25th percentile of cervical length.
The Lancet  , DOI: ( /S (13) )
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