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NCT Number: NCT06999278

LIGHT Trial: Levothyroxine for Gestational Hypothyroidism in Recurrent Pregnancy Loss

The goal of this randomized, double-blind, placebo-controlled clinical trial is to evaluate whether levothyroxine supplement improves pregnancy outcomes in women with recurrent pregnancy loss (RPL) and isolated maternal hypothyroidism (IMH).

The main questions it aims to answer are:

Does levothyroxine increase the live birth rate after 24 weeks of gestation? Does levothyroxine improve secondary outcomes such as ongoing pregnancy rates, reduce the incidence of pregnancy loss, or influence maternal and neonatal complications?

Researchers will:

Compare the levothyroxine treatment group (50 µg/day) to the placebo group to assess the impact of the intervention on live birth rates and other pregnancy outcomes.

Participants will:

Be randomly assigned to receive either levothyroxine or a placebo. Take the assigned treatment daily starting from enrollment until the end of pregnancy.

Undergo routine follow-up visits to monitor pregnancy progress and outcomes. This trial seeks to determine whether routine levothyroxine supplementation can improve pregnancy outcomes for women with RPL and IMH.

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Key information

Conditions

Abortion, Habitual Abortion, Spontaneous Female Urogenital Diseases and Pregnancy Complications Pregnancy Complications Urogenital Diseases

Age range

18 year–40 year

Sex eligibility

Female

Study type

Interventional

Phase

Phase 3

Primary location

Zhejiang People's Hospital, Hangzhou, Zhejiang, China

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About this study

Investigators will perform a multi-center, randomized, placebo, double-blind clinical trial of levothyroxine (LT4) in patients aged between 18 years and 40 yearls who are diagnosed with isolated hypothyroxemia (defined as lower FT4 level with normal TSH) and have a previous history of recurrent miscarriages (defined as two or more pregnancy loss). Investigators will assess the effects of standard dose of 50ug/d levothyroxine therapy from the day after randomization to the day of delivery on the pregnancy outcomes, including live birth, neonatal complications, and adverse pregnancy outcomes, etc.

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • women with singleton pregnancy
  • women with a history of recurrent pregnancy loss (defined as two or more pregnancy loss before 20wks)
  • women diagnosed with isolated maternal hypothyroidism (defined as isolated lower level of FT4 with normal TSH levels) in the current pregnancy before 20wks

Exclusion criteria

  • patients with known thyroid disorders
  • patients with antiphospholipid syndrome or other autoimmune conditions
  • patients with contraindications to levothyroxine (e.g., acute cardiac arrest, acute pancreatitis, acute myocarditis)
  • patients attending other ongoing clinical trials or unwilling to participate.

Treatment and study plan

levothyroxin

Drug

Levothyroxin 50ug/d from randomization until delivery

Placebo

Drug

Placebo to levothyroxin

Primary outcomes

  1. Live birth after 28 weeks of gestation

    Time frame: From the enrollment to the day of delivery after 28+0 weeks of gestation

    Live birth following spontaneous labor or iatrogenic delivery after 28+0 weeks of gestation (196 days from the participant's last menstrual period)

Secondary outcomes

  1. Ongoing pregnancy at 7 weeks of gestation

    Time frame: From the day of randomization to the 7 weeks of gestation

    ultrasound diagnosis of ongoing pregnancy at 7 weeks of gestation

  2. Ongoing pregnancy at 12 weeks of gestation

    Time frame: From the day of randomization to the 12 weeks of gestation

    ultrasound diagnosis of ongoing pregnancy at 12 weeks of gestation

  3. Ongoing pregnancy at 24 weeks of gestation

    Time frame: From the day of randomization to the 24 weeks of gestation

    ultrasound diagnosis of ongoing pregnancy at 24 weeks of gestation

  4. Miscarriage

    Time frame: From enrollment to 19+6 weeks of gestation

    pregnancy loss before 20 weeks of gestation

  5. Stillbirth

    Time frame: From enrollment to the day of delivery of the dead fetus from 20+0 weeks onward

    fetal death delivered beyond 20 weeks of gestation

  6. Ectopic pregnancy

    Time frame: From enrollment to the end of treatment up to 20 weeks

    ultrasound diagnosis of ectopic pregnancy

  7. Abortion

    Time frame: From enrollment to the day of termination of pregnancy up to 27+6 weeks

    personal request the termination of pregnancy without medical conditions

  8. Need for cervical cerclage

    Time frame: From enrollment to the day of cervical cerlage performed up to 27+6 weeks

    medically indicated cervical cerclage up to 27+6 weeks of gestation

  9. Preterm birth

    Time frame: From enrollment to the day of preterm birth between 28+0 and 36+6 weeks

    live birth between 28+0 and 36+6 weeks of gestation

  10. Gestational age at delivery

    Time frame: up to delivery

    Gestational age at delivery

  11. Antepartum complications

    Time frame: From enrollment to the day of delivery, up to 42+0 weeks

    including: preeclampsia, gestational diabetes, fetal growth restriction

  12. Intrapartum complications

    Time frame: up to delivery

    including: fetal distress, dystocia, fever

  13. Postpartum complications

    Time frame: up to 42 days after childbirth

    including: postpartum hemorrhage, infection, fever

  14. Neonatal birthweight

    Time frame: up to delivery

    the birthweight of the neonate: unit (kg)

  15. Neonatal APGAR score

    Time frame: up to 5 minutes after delivery

    Neonatal APGAR score at 1 and 5 minutes

  16. Neonatal complications

    Time frame: up to 7 days after delivery

    include neonatal breathing disorders, neonatal infections, neonatal asphyxia, neonatal jaundice, NICU admission for any other causes

Other outcomes

  1. Adverse outcomes related to levothyroxine treatment

    Time frame: From enrollment to the end of treatment, up to 40 weeks

    unexpected medical event in a patient or clinical trial participant receiving a pharmaceutical product, which may not necessarily be causally related to the treatment

Study contacts

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

Qiong Luo, Ph.D.

CONTACT

[email protected]

+86 571 89998819

Zixing Zhong, MSc

CONTACT

[email protected]

+86 571 85893328

Sponsors and collaborators

Lead sponsor

Women's Hospital School Of Medicine Zhejiang University

Other

Collaborators

  • Zhejiang Provincial People's Hospital

Registry information

Official study title

LIGHT - Levothyroxine for Isolated Gestational HypoThyroidism in Women With Recurrent Pregnancy Loss: a Multicenter Randomized, Double-blind, Placebo-controlled Trial - a Study Protocol

Acronym: LIGHT

Important dates

Study start
2025
Primary completion
2027
Study completion
2027
First posted
May 31, 2025
Registry last updated
Jun 4, 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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