Twin PregnancyTWiSTNCT07164001
Twins With Specific vs. Traditional Fetal Growth Charts
A study testing Twin-Specific Growth Chart Interpretation and Singleton-Based Growth Chart Interpretation in people with Twin Pregnancy, run by Indiana University.
Trial summary
This study aims to compare how well two different types of fetal growth charts work in tracking the growth of twins during pregnancy. These charts help doctors decide if a fetus is growing normally. One type is commonly used for all pregnancies, while the other is specially designed for twin pregnancies. Read more about this study
- Who is it for?
- Ages 18 years and older, women only
- Conditions the study is for
- Twin Pregnancy
- What is being tested?
- Twin-Specific Growth Chart Interpretation and Singleton-Based Growth Chart Interpretation
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 150 participants
- Where
- No sites listed yet
- Study dates
- 1 Jan 2026to 28 Jan 2030
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- Women only
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Pregnant individuals with a twin pregnancy of at least 18 weeks gestation.
- Willing and able to provide informed consent.
- Planning to deliver at a participating center.
Who cannot join
- Major fetal anomalies or known aneuploidy.
- Significant maternal medical conditions that might confound study outcomes.
- Inability to comply with study procedures.
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Official title: Twins With Specific vs. Traditional Fetal Growth Charts (TWiST): A Randomized Controlled Trial
This study aims to compare how well two different types of fetal growth charts work in tracking the growth of twins during pregnancy. These charts help doctors decide if a fetus is growing normally. One type is commonly used for all pregnancies, while the other is specially designed for twin pregnancies. The study will enroll pregnant individuals carrying twins. Participants will be randomly assigned to have their care guided by either the traditional chart or the twin-specific chart. Researchers will compare outcomes such as birth weight, timing of delivery, and newborn health. The goal is to find out if using twin-specific charts can improve care and reduce unnecessary interventions.
Read the detailed description
Twin pregnancies are at increased risk for growth abnormalities and adverse perinatal outcomes. Despite physiological differences in fetal growth patterns between singleton and twin pregnancies, most clinical decisions in the United States still rely on singleton-based fetal growth charts. This randomized controlled trial (RCT) evaluates whether using twin-specific fetal growth charts to guide clinical care results in better perinatal outcomes compared to using standard singleton-based charts.
Participants will be pregnant individuals with twin gestations receiving routine prenatal care at participating clinical sites. Eligible participants will be randomized to one of two groups: (1) management based on singleton growth charts or (2) management based on twin-specific charts. Both charts will be used to assess fetal growth during ultrasound visits, but only the chart assigned to the participant's group will inform clinical decision-making. Data will be collected on outcomes including birth weight, small-for-gestational-age (SGA) classification, gestational age at delivery, NICU admissions, and neonatal morbidity.
The study aims to determine whether using twin-specific fetal growth standards can reduce the overdiagnosis of growth restriction and the associated risks of iatrogenic preterm delivery and unnecessary interventions. Results may support more tailored approaches to growth assessment in twin pregnancies.
- Conditions
- Twin Pregnancy
- Being tested
- Twin-Specific Growth Chart Interpretation, Singleton-Based Growth Chart Interpretation
- Keywords
- Twin-Specific Growth Chart, Singleton-Based Growth Chart, Fetal Biometry, Small for Gestational Age, Growth Assessment, Perinatal Outcomes, Randomized Controlled Trial, Prenatal Ultrasound, Twin Gestation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Twin-Specific Growth Chart InterpretationOther
Also called TWiST-Twin Chart
Participants in this arm will have their fetal growth assessed using twin-specific growth charts. These charts account for twin gestation norms and may influence clinical decision-making regarding growth restriction and perinatal management. The intervention does not involve any direct physical procedure or device but rather a change in the interpretation framework of routinely collected ultrasound data.
Singleton-Based Growth Chart InterpretationOther
Also called TWiST-Singleton Chart
Participants in this arm will have their fetal growth assessed using singleton-based growth charts. These charts are commonly used in standard practice but may overestimate growth restriction in twin pregnancies. The intervention does not involve any direct physical procedure or device but alters the interpretation framework for standard prenatal ultrasound findings.
| Study group | Role | What they receive |
|---|---|---|
| Twin-Specific Growth Chart Group | Experimental | Participants in this arm will receive prenatal ultrasound assessments interpreted using a twin-specific growth chart for estimated fetal weight and biometry. Clinical decisions and perinatal risk assessments will be guided based on twin-specific percentiles. Receives: Other: Twin-Specific Growth Chart Interpretation |
| Singleton-Based Growth Chart Group | Active comparator | Participants in this arm will receive prenatal ultrasound assessments interpreted using a singleton-based growth chart for estimated fetal weight and biometry. Clinical decisions and perinatal risk assessments will be based on singleton percentiles, which represent standard practice in many settings. Receives: Other: Singleton-Based Growth Chart Interpretation |
What is being measured
The primary outcome is the main question the study is designed to answer.
Rate of Small for Gestational Age (SGA) Diagnosis Based on Ultrasound Biometry
The primary outcome is the incidence of small for gestational age (SGA) diagnosis among twin pregnancies, as determined by fetal biometry assessed during prenatal ultrasound using either twin-specific or singleton-based growth charts. SGA is defined as an estimated fetal weight below the 10th percentile for gestational age according to the respective chart used in each study arm.
Measured: At delivery (up to 42 weeks gestation)
Secondary outcomes (4)
Rate of Neonatal Composite Morbidity
Composite includes one or more of the following: CPAP use >72 hours, intraventricular hemorrhage (IVH), necrotizing enterocolitis (NEC), neonatal hypoglycemia requiring IV therapy, or neonatal death.
Measured: Delivery through neonatal hospital discharge (up to 28 days of life)
Rate of NICU Admission
Percentage of neonates admitted to the Neonatal Intensive Care Unit (NICU) following delivery, as documented in clinical records.
Measured: At delivery
Birthweight Discordance Between Twins
Defined as the percentage difference in birthweight between the two fetuses in each twin pair. Discordance >20% will be considered clinically significant.
Measured: At delivery
Gestational Age at Delivery
Measured in completed weeks of gestation at the time of birth, based on clinical and ultrasound dating.
Measured: At delivery
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Sep 2025
- Study start1 Jan 2026 (estimated)
- Primary completion31 Dec 2029 (estimated)
- Study completion28 Jan 2030 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Twin PregnancyStudies of the same condition, open and under way.
- More trials run by Indiana UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Diagnosis
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Participants with twin pregnancies are randomly assigned to either the intervention arm (twin-specific fetal growth chart) or the control arm (singleton-based fetal growth chart). The two groups will be followed in parallel throughout the study period to compare diagnostic accuracy and clinical outcomes. No crossover between arms will occur. Ultrasound measurements and clinical decision-making will adhere to the assigned chart type.
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 150 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Indiana University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Hiba Mustafa, Indiana University
- Investigators
- Hiba Mustafa, MD, Principal investigator, Indiana University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07164001
- Sponsor's protocol ID
- 27427
- Acronym
- TWiST
- Status last verified
- Sep 2025
- First submitted
- 1 Sep 2025
- Last updated
- 15 Sep 2025
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 15 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Twins With Specific vs. Traditional Fetal Growth Charts (TWiST): A Randomized Controlled Trial
- ClinicalTrials.gov ID
- NCT07164001
- Acronym / sponsor ID
- TWiST / 27427
- Conditions
- Twin Pregnancy
- Keywords
- Twin-Specific Growth Chart, Singleton-Based Growth Chart, Fetal Biometry, Small for Gestational Age, Growth Assessment, Perinatal Outcomes, Randomized Controlled Trial, Prenatal Ultrasound
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 150 participants (estimated)
- Lead sponsor
- Indiana UniversityUniversity, hospital or other
- Study start
- 1 Jan 2026 (estimated)
- Primary completion
- 31 Dec 2029 (estimated)
- Study completion
- 28 Jan 2030 (estimated)
- First posted
- 9 Sep 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study aims to compare how well two different types of fetal growth charts work in tracking the growth of twins during pregnancy. These charts help doctors decide if a fetus is growing normally. One type is commonly used for all pregnancies, while the other is specially designed for twin pregnancies. The study will enroll pregnant individuals carrying twins. Participants will be randomly assigned to have their care guided by either the traditional chart or the twin-specific chart. Researchers will compare outcomes such as birth weight, timing of delivery, and newborn health. The goal is to find out if using twin-specific charts can improve care and reduce unnecessary interventions.
Detailed description
Twin pregnancies are at increased risk for growth abnormalities and adverse perinatal outcomes. Despite physiological differences in fetal growth patterns between singleton and twin pregnancies, most clinical decisions in the United States still rely on singleton-based fetal growth charts. This randomized controlled trial (RCT) evaluates whether using twin-specific fetal growth charts to guide clinical care results in better perinatal outcomes compared to using standard singleton-based charts.
Participants will be pregnant individuals with twin gestations receiving routine prenatal care at participating clinical sites. Eligible participants will be randomized to one of two groups: (1) management based on singleton growth charts or (2) management based on twin-specific charts. Both charts will be used to assess fetal growth during ultrasound visits, but only the chart assigned to the participant's group will inform clinical decision-making. Data will be collected on outcomes including birth weight, small-for-gestational-age (SGA) classification, gestational age at delivery, NICU admissions, and neonatal morbidity.
The study aims to determine whether using twin-specific fetal growth standards can reduce the overdiagnosis of growth restriction and the associated risks of iatrogenic preterm delivery and unnecessary interventions. Results may support more tailored approaches to growth assessment in twin pregnancies.
Study design
- Primary purpose
- Diagnosis
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 2
- Model description
- Participants with twin pregnancies are randomly assigned to either the intervention arm (twin-specific fetal growth chart) or the control arm (singleton-based fetal growth chart). The two groups will be followed in parallel throughout the study period to compare diagnostic accuracy and clinical outcomes. No crossover between arms will occur. Ultrasound measurements and clinical decision-making will adhere to the assigned chart type.
| Arm | Type | Receives |
|---|---|---|
| Twin-Specific Growth Chart Group | Experimental | Other: Twin-Specific Growth Chart InterpretationParticipants in this arm will receive prenatal ultrasound assessments interpreted using a twin-specific growth chart for estimated fetal weight and biometry. Clinical decisions and perinatal risk assessments will be guided based on twin-specific percentiles. |
| Singleton-Based Growth Chart Group | Active comparator | Other: Singleton-Based Growth Chart InterpretationParticipants in this arm will receive prenatal ultrasound assessments interpreted using a singleton-based growth chart for estimated fetal weight and biometry. Clinical decisions and perinatal risk assessments will be based on singleton percentiles, which represent standard practice in many settings. |
Who may qualify
- Ages
- 18 years and older
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Pregnant individuals with a twin pregnancy of at least 18 weeks gestation.
- Willing and able to provide informed consent.
- Planning to deliver at a participating center.
Key exclusion criteria (3 listed)
- Major fetal anomalies or known aneuploidy.
- Significant maternal medical conditions that might confound study outcomes.
- Inability to comply with study procedures.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Twin-Specific Growth Chart InterpretationAlso: TWiST-Twin ChartParticipants in this arm will have their fetal growth assessed using twin-specific growth charts. These charts account for twin gestation norms and may influence clinical decision-making regarding growth restriction and perinatal management. The intervention does not involve any direct physical procedure or device but rather a change in the interpretation framework of routinely collected ultrasound data. | Other | Twin-Specific Growth Chart Group |
| Singleton-Based Growth Chart InterpretationAlso: TWiST-Singleton ChartParticipants in this arm will have their fetal growth assessed using singleton-based growth charts. These charts are commonly used in standard practice but may overestimate growth restriction in twin pregnancies. The intervention does not involve any direct physical procedure or device but alters the interpretation framework for standard prenatal ultrasound findings. | Other | Singleton-Based Growth Chart Group |
Primary outcome
Rate of Small for Gestational Age (SGA) Diagnosis Based on Ultrasound Biometry
Time frame: At delivery (up to 42 weeks gestation)
The primary outcome is the incidence of small for gestational age (SGA) diagnosis among twin pregnancies, as determined by fetal biometry assessed during prenatal ultrasound using either twin-specific or singleton-based growth charts. SGA is defined as an estimated fetal weight below the 10th percentile for gestational age according to the respective chart used in each study arm.
4 secondary outcomes
Rate of Neonatal Composite Morbidity
Time frame: Delivery through neonatal hospital discharge (up to 28 days of life)
Rate of NICU Admission
Time frame: At delivery
Birthweight Discordance Between Twins
Time frame: At delivery
Gestational Age at Delivery
Time frame: At delivery
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 15 Sep 2025.
- Individual participant dataSharing planned: Undecided
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Is the Vaginal Microbiome and Metabolome Associated With Spontaneous Preterm Birth (sPTB) in Multiple Pregnancies?
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MoDi Twin Placental Imaging
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Twin Pregnancy Cohort
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Hiba Mustafa, MD principal investigator
Indiana University
Questions about this trial
What is this clinical trial studying?
A study testing Twin-Specific Growth Chart Interpretation and Singleton-Based Growth Chart Interpretation in people with Twin Pregnancy, run by Indiana University.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 15 Sep 2025. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Emrah Aydin, MD, PhD, MBA, MSc (5132202779, eaydin@iu.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Rate of Small for Gestational Age (SGA) Diagnosis Based on Ultrasound Biometry (time frame: At delivery (up to 42 weeks gestation)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 15 Sep 2025.