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Randomized Controlled Trial of Vaginal Progesterone in Women With Threatened Preterm Labor (PROTO)

This study has been terminated.
(Trial investigators were unable to recruit the estimated sample)
Information provided by (Responsible Party):
Dr. Sue Ross, University of Calgary Identifier:
First received: January 27, 2011
Last updated: January 7, 2015
Last verified: January 2015

Prematurity remains the most important single factor in perinatal morbidity and mortality. Unfortunately, the rate of premature delivery is increasing in Canada and is especially high in Alberta with 7.5% of pregnancies ending before 37 weeks gestation. Despite years of research into the causes of spontaneous preterm labor, few effective treatments have been identified. Progesterone is one candidate treatment. The purpose of this study is to investigate whether progesterone can prolong pregnancy in women who have symptoms of preterm labor.

Pregnant women who have symptoms of premature labor will be invited to take part in the study if they are between 22 to 24 weeks pregnant. If they agree to join the study, they will be randomly allocated to either take progesterone 200mg each day via the vagina until 36 weeks, or to take a placebo preparation. Neither the women nor their clinician will know which group they are in.

Women and their babies will be followed until 28 days after the birth, to find out about the length of the pregnancy, any adverse events that might occur (none have been reported in previous trials), and to look at whether women have taken the treatment.

When the study is complete, the results for the progesterone group will be compared to the placebo group. If progesterone is found to be useful in helping to prolong pregnancy, then this will be a possible treatment to help mothers in the future.

Condition Intervention Phase
Obstetric Labor, Premature
Drug: Vaginal progesterone
Drug: Placebo
Phase 4

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double Blind (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: Pilot Randomized Controlled Trial of Vaginal Progesterone to Prevent Preterm Birth in Women With Threatened Preterm Labor

Resource links provided by NLM:

Further study details as provided by University of Calgary:

Primary Outcome Measures:
  • Gestational age at birth [ Time Frame: At birth ]
    Gestational age at birth calculated from gestational age at pre-randomization baseline

Secondary Outcome Measures:
  • Proportion of women who have preterm birth <35 weeks [ Time Frame: At birth ]
  • Proportion of women who have a preterm birth at <37 weeks [ Time Frame: At birth ]
  • Maternal hospital length of stay (days) [ Time Frame: Days from date of admission to date of discharge ]
  • Proportion of women who have hospital admission for premature labor [ Time Frame: After birth ]
  • Maternal compliance with treatment [ Time Frame: At time of birth ]
    Diary self-report of treatment use

  • Neonatal hospital length of stay (days) [ Time Frame: Days from birth to discharge from hospital ]
  • Neonatal morbidity [ Time Frame: Up to 28 days after birth ]
    Respiratory distress syndrome (type 1), intraventricular hemorrhage, chronic lung disease, periventricular leukomalacia,necrotising eneterocolitis, retinopathy of prematurity

  • Number of days of assisted ventilation (neonate) [ Time Frame: Up to 28 days after birth ]
  • Number of days of supplemental oxygen (for neonate) [ Time Frame: Up to 28 days after birth ]
  • Birth weight (grams) [ Time Frame: At time of birth ]
  • Neonatal survival to discharge home (yes/no) [ Time Frame: During 28 days after birth ]
  • Adverse events (maternal or neonate) [ Time Frame: Up to 28 days after birth ]

Enrollment: 34
Study Start Date: January 2011
Study Completion Date: October 2014
Primary Completion Date: October 2014 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Vaginal progesterone Drug: Vaginal progesterone
Capsules of 200mg micronised progesterone suspended in sunflower oil. One capsule inserted vaginally per day from time of randomisation to gestational age 35(+6)weeks or delivery (if sooner).
Other Name: Utrogestan
Placebo Comparator: Placebo Drug: Placebo
Capsules of placebo (sunflower oil). One capsule inserted vaginally per day from time of randomisation to gestational age 35(+6)weeks or delivery (if sooner).


Ages Eligible for Study:   18 Years to 50 Years   (Adult)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Women with symptomatic premature contractions successfully arrested for at least 12 hours with tocolytics.
  • Women with symptoms suggestive of early preterm labor whose contractions resolve without tocolysis but are fetal fibronectin positive.
  • Gestational age 23(+0)-32(+6) weeks.
  • Consent to taking part in the study.

Exclusion Criteria:

  • Placenta previa
  • Preterm premature rupture of membranes at presentation
  • Pre-existing hypertension will be excluded in order to reduce the likelihood of iatrogenic preterm delivery within the study women
  • Known major fetal anomaly detected on ultrasound
  • Multiple pregnancy
  • Maternal seizure disorder
  • Active or history of thromboembolic disease
  • Maternal liver disease
  • Known or suspected breast malignancy or pathology
  • Known or suspected progesterone-dependent neoplasia
  • Plans to move to another city during pregnancy
  • Previous participation in a progesterone trial during this pregnancy
  • Known sensitivity to progesterone
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT01286246

Canada, Alberta
Foothills Medical Centre
Calgary, Alberta, Canada, T2N 4J8
Sponsors and Collaborators
University of Calgary
Principal Investigator: Stephen Wood, MD, MSc University of Calgary
  More Information

Responsible Party: Dr. Sue Ross, Associate Professor, University of Calgary Identifier: NCT01286246     History of Changes
Other Study ID Numbers: 21492
Study First Received: January 27, 2011
Last Updated: January 7, 2015

Keywords provided by University of Calgary:
Randomized controlled trial

Additional relevant MeSH terms:
Obstetric Labor, Premature
Obstetric Labor Complications
Pregnancy Complications
Hormones, Hormone Substitutes, and Hormone Antagonists
Physiological Effects of Drugs processed this record on May 22, 2017