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NCT Number: NCT07164001

Twins With Specific vs. Traditional Fetal Growth Charts

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.

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Key information

Conditions

Age range

18 year and older

Sex eligibility

Female

Study type

Interventional

Phase

Not applicable

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 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.

Exclusion criteria

  • Major fetal anomalies or known aneuploidy.
  • Significant maternal medical conditions that might confound study outcomes.
  • Inability to comply with study procedures.

Treatment and study plan

Twin-Specific Growth Chart Interpretation

Other

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.

Other names: TWiST-Twin Chart

Singleton-Based Growth Chart Interpretation

Other

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.

Other names: TWiST-Singleton Chart

Primary outcomes

  1. 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.

Secondary outcomes

  1. Rate of Neonatal Composite Morbidity

    Time frame: Delivery through neonatal hospital discharge (up to 28 days of life)

    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.

  2. Rate of NICU Admission

    Time frame: At delivery

    Percentage of neonates admitted to the Neonatal Intensive Care Unit (NICU) following delivery, as documented in clinical records.

  3. Birthweight Discordance Between Twins

    Time frame: At delivery

    Defined as the percentage difference in birthweight between the two fetuses in each twin pair. Discordance >20% will be considered clinically significant.

  4. Gestational Age at Delivery

    Time frame: At delivery

    Measured in completed weeks of gestation at the time of birth, based on clinical and ultrasound dating.

Study contacts

Contact information is provided by the study sponsor or research team.

Emrah Aydin, MD, PhD, MBA, MSc

CONTACT

[email protected]

5132202779

Sponsors and collaborators

Lead sponsor

Indiana University

Other

Registry information

Official study title

Twins With Specific vs. Traditional Fetal Growth Charts (TWiST): A Randomized Controlled Trial

Acronym: TWiST

Important dates

Study start
2026
Primary completion
2029
Study completion
2030
First posted
Sep 9, 2025
Registry last updated
Sep 15, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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