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The CHIPS Trial (Control of Hypertension In Pregnancy Study)

This study has been completed.
Canadian Institutes of Health Research (CIHR)
Sunnybrook Research Institute
Information provided by (Responsible Party):
University of British Columbia Identifier:
First received: August 30, 2010
Last updated: November 15, 2016
Last verified: November 2016

The investigators do not know which approach to treatment of non-severe high blood pressure in pregnancy is better for women and babies.

In the CHIPS Trial, the investigators seek to determine whether 'less tight' control (aiming for a diastolic blood pressure [dBP] of 100 mmHg), compared with 'tight' control (aiming for a diastolic blood pressure [dBP] of 85 mmHg) can decrease the risks of adverse baby outcomes without increasing the risk of problems for the mother.

Condition Intervention
Gestational Hypertension
Procedure: Intervention is blood pressure management approach
Procedure: Intervention is blood pressure management approach.

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: The CHIPS Trial (Control of Hypertension In Pregnancy Study)

Resource links provided by NLM:

Further study details as provided by University of British Columbia:

Primary Outcome Measures:
  • Pregnancy Loss or NICU Admission for Greater Than 48 Hours [ Time Frame: 6 weeks ]
    Pregnancy loss or NICU admission for greater than 48 hours, as recorded in the maternal and infant medical records immediately following the birth (or pregnancy loss), and then again after the mothers' and infants' discharge home. Supplemental information, about potential post-discharge maternal or neonatal morbidities in the 6 weeks following birth for the mother, or 28 days of life for the baby, will be obtained by contacting women at 6 weeks postpartum and/or from medical records.

Secondary Outcome Measures:
  • Serious Maternal Complications Measured up to 6 Weeks Postpartum [ Time Frame: 6 weeks ]

    Serious maternal complications measured up to 6 weeks postpartum. Death or one or more life-threatening maternal complications:

    1. Adverse neurological complications (stroke, eclampsia, and/or blindness), and/or
    2. End-organ failure (uncontrolled hypertension, inotropic support, pulmonary oedema, respiratory failure, myocardial ischaemia/infarction, renal failure, coagulopathy, and/or transfusion)

Enrollment: 987
Study Start Date: April 2009
Study Completion Date: February 2014
Primary Completion Date: February 2014 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: 'Less tight' control.
The diastolic blood pressure (dBP) treatment goal is 100 mmHg.
Procedure: Intervention is blood pressure management approach
1) 'Less tight' control. The dBP treatment goal is 100 mmHg. For safety, if dBP is >105 mmHg, then antihypertensive medication must be started or increased in dose. For dBP <100 mmHg, antihypertensive therapy should be decreased in dose or stopped, as appropriate. The intervention will be applied until delivery.
Active Comparator: 'Tight' control.
The diastolic blood pressure (dBP) treatment goal is 85 mmHg.
Procedure: Intervention is blood pressure management approach.
'Tight' control. The dBP treatment goal is 85 mmHg. For safety, if dBP is <80 mmHg, then antihypertensive medication must be decreased in dose or discontinued. If dBP is >85 mmHg, then antihypertensive therapy should be started or increased in dose. The intervention will be applied until delivery.

Detailed Description:

Primary research question:

For pregnant women with non-severe, non-proteinuric maternal hypertension at 14-33 weeks, will 'less tight' control (target diastolic blood pressure [dBP] of 100 mmHg) versus 'tight' control (target dBP of 85 mmHg) increase (or decrease) the likelihood of pregnancy loss or Neonatal Intensive Care Unit (NICU) admission for greater than 48 hours?

Secondary research question:

Will 'less tight' versus 'tight' control increase (or decrease) the likelihood of serious maternal complications?

Other research questions:

Will 'less tight' versus 'tight' control:

  1. Increase (or decrease) the likelihood of serious perinatal complications?
  2. Increase (or decrease) the likelihood of severe hypertension and pre-eclampsia?
  3. Increase (or decrease) the likelihood of maternal satisfaction with care?
  4. Result in significant changes in dBP or health care costs?

Treatment Allocation:

Eligible women will be randomised centrally to either 'less tight' control (aiming for dBP of 100mmHg) or 'tight' control (aiming for dBP of 85mmHg) of their hypertension.

Randomisation will be stratified by centre and type of hypertension (pre-existing or gestational).

  • In the 'less tight' control group, if dBP is ≥105mmHg, then antihypertensive medication must be started or increased in dose.
  • In the 'tight' control group, if dBP is ≤80mmHg, then antihypertensive medication must be decreased in dose or discontinued.
  • In both groups, centres will provide their usual care. Data will be collected on potential co-interventions (e.g., hospitalisation, bedrest).


Primary: Pregnancy loss (miscarriage or ectopic pregnancy, pregnancy termination, stillbirth, or neonatal death) or high level neonatal care for >48 hours in the first 28 days of life or prior to primary hospital discharge, whichever is later.

Secondary: One/more serious maternal complication(s) until six weeks postpartum.


Compliance (dBP and antihypertensive dose) will be assessed within 4 weeks of randomisation. Outcome data will be collected during the woman's (and baby's) hospital stay for birth (or loss). Women will be contacted 6 to 12 weeks after delivery (or loss) and, for preterm babies, when the baby is at 36 weeks corrected gestational age to enquire about satisfaction with care and any major maternal/neonatal morbidity following hospital discharge.


Ages Eligible for Study:   Child, Adult, Senior
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  1. Pre-existing or gestational hypertension (pre-existing hypertension is dBP greater than or equal to 90 mmHg before pregnancy or 20 weeks' gestation; gestational hypertension is dBP greater than or equal to 90 mmHg that develops after 20 weeks)
  2. dBP of 90 - 105 mmHg if NOT TAKING antihypertensive therapy, or dBP of 85 - 105 mmHg if TAKING antihypertensive therapy
  3. Live foetus (confirmed by Doptone assessment of foetal heart tones within one week before randomisation)
  4. Gestational age 14 - 33+6 weeks (as measured by last menstrual period or dating ultrasound)

Exclusion Criteria:

  1. Severe systolic hypertension (defined as a systolic blood pressure [sBP] greater than or equal to 160 mmHg at randomisation)
  2. Proteinuria (defined as greater than or equal to 0.3 g/d by 24 hour urine collection, or if a 24 hour urine collection is not available, by a urinary protein:creatinine ratio of greater than or equal to 30 mg/mmol or urinary dipstick of greater than or equal to 2+)
  3. Use of an angiotensin converting enzyme (ACE) inhibitor at greater than or equal to 14+0 weeks' gestation
  4. Contraindication to either arm of the trial or to pregnancy prolongation
  5. Known multiple gestation
  6. Known lethal or major foetal anomaly
  7. Plan to terminate pregnancy
  8. Prior participation in CHIPS
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Please refer to this study by its identifier: NCT01192412

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Osorno, Chile
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Blackburn, United Kingdom
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Chesterfield, United Kingdom
University Hospital Coventry and Warwickshire
Coventry, United Kingdom
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Leicester, United Kingdom
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South Warwickshire NHS Trust
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New Cross Hospital
Wolverhampton, United Kingdom
York District Hospital
York, United Kingdom
Sponsors and Collaborators
University of British Columbia
Canadian Institutes of Health Research (CIHR)
Sunnybrook Research Institute
Principal Investigator: Laura A Magee, MD, FRCPC, MSc, FACP The University of British Columbia
  More Information

Publications automatically indexed to this study by Identifier (NCT Number):

Responsible Party: University of British Columbia Identifier: NCT01192412     History of Changes
Obsolete Identifiers: NCT01081171
Other Study ID Numbers: H08-00882
MCT-87522 ( Other Grant/Funding Number: CIHR )
07-3431 ( Other Identifier: UBC )
Study First Received: August 30, 2010
Results First Received: August 30, 2016
Last Updated: November 15, 2016

Keywords provided by University of British Columbia:
antihypertensive therapy
perinatal outcome
maternal outcome
Non-severe, non-proteinuric pre-existing or gestational hypertension in pregnancy

Additional relevant MeSH terms:
Hypertension, Pregnancy-Induced
Vascular Diseases
Cardiovascular Diseases
Pregnancy Complications
Antihypertensive Agents processed this record on May 25, 2017