Status
Recruiting
Phase
Not applicable
Enrollment
792
Locations
1
Results
Not posted
Publications
1
Study summary
This study aims to evaluate the efficacy of atosiban in patients with previous pregnancy failure and abnormal uterine contractions during the peri-embryo transfer period in assisted reproductive technology. The main questions it aims to answer are: * Does the use of atosiban in patients with a history of implantation failure and abnormal uterine contractions affect the live birth rate in single blastocyst transfer cycles (fresh or frozen-thawed embryo transfer)? * Evaluate the differences in efficacy of atosiban regarding perinatal complications and neonatal outcomes, as well as differences in safety concerning miscarriage rates and ectopic pregnancy rates. Researchers will compare atosiban with placebo (a similar substance containing no active medication) to determine whether atosiban is effective in improving live birth rates from single blastocyst transfer cycles (fresh or frozen-thawed embryo transfer) in patients with a history of implantation failure and abnormal uterine contractions. * Participants allocated to the Atosiban group will be administered Atosiban (37.5 mg/5 mL, Tractocile®, Ferring Pharma, Geneva, Switzerland) as an intravenous (IV) bolus of 6·75 mg/0.9 mL in 1 minute at 30 minutes prior to the ET procedure, followed by an IV infusion at a rate of 18 mg/h for 1 hour; after 1 hour, the dose of Atosiban will be reduced to 6 mg/h, with a total dose of 37.5 mg. Participants allocated to the placebo group will receive identical-looking saline infusions for the same duration. * One hour post-embryo transfer, all randomized participants will be invited to have a reevaluation of uterine wave patterns via ultrasound, performed by the same examiner. * Women who had a clinical pregnancy will be subsequently contacted by nurses to document pregnancy events and outcomes at 12 and 24 weeks of gestation, completion of pregnancy, with a follow-up approximately 6 weeks post-delivery. Those participants who had a negative pregnancy test will not be followed up any further as part of this trial.
Interventions
DRUG
Participants allocated to the Atosiban group will be administered Atosiban (37.5 mg/5 mL, Tractocile®, Ferring Pharma, Geneva, Switzerland) as an intravenous (IV) bolus of 6·75 mg/0.9 mL in 1 minute at 30 minutes prior to the ET procedure, followed by an IV infusion at a rate of 18 mg/h for 1 hour; after 1 hour, the dose of Atosiban will be reduced to 6 mg/h, with a total dose of 37.5 mg.
DRUG
Participants allocated to the placebo group will receive identical-looking saline infusions for the same duration.
Timeline
First posted
Sep 22, 2025
Study start
Dec 6, 2025
Primary completion
Jun 30, 2027
Study completion
Sep 30, 2027
Results posted
Not reported
Registry updated
Dec 9, 2025
Outcomes
Live birth
Time frame · After 24 weeks of gestation
Live birth is defined as the delivery of at least one newborn who exhibits any sign of life.
Biochemical pregnancy
Time frame · 12 days after blastocyst transfer
Biochemical pregnancy is defined as serum beta-human chorionic gonadotropin β-hCG\> 10 IU/L 12 days after blastocyst transfer.
Clinical pregnancy
Time frame · 6-8 weeks after blastocyst transfer.
Clinical pregnancy is defined as observed gestational sac or definitive clinical signs of pregnancy observed at ultrasonography (including clinically documented ectopic pregnancy)
Ongoing pregnancy
Time frame · After 12 weeks of gestation
Ongoing pregnancy is defined as the presence of a gestational sac and fetal heartbeat after 12 weeks of gestation.
Miscarriage
Time frame · before 20 weeks of gestation.
Miscarriage is defined as spontaneous loss of an intrauterine pregnancy prior to 20 completed weeks of gestational age.
Stillbirth
Time frame · after 20 weeks of gestation
Stillbirth is defined as the death of a fetus prior to the complete expulsion or extraction from its mother after 20 completed weeks of gestational age including deaths during labor.
Ectopic pregnancy
Time frame · After 4 to 6 weeks of embryo transfer
Ectopic pregnancy is defined as a pregnancy outside the uterine cavity, diagnosed by ultrasound, surgical visualization, or histopathology.
Multiple pregnancy
Time frame · 7 weeks of gestation
Multiple pregnancy is defined as a pregnancy with two or more gestational sacs or positive heart beats at 7 weeks of gestation.
Gestational diabetes mellitus
Time frame · At 28 weeks of pregnancy
Newly diagnosed diabetes or gestational diabetes at 28 weeks of pregnancy confirmed by 75 g oral glucose tolerance test.
hypertensive disorders of pregnancy
Time frame · From 20 weeks of gestation up to at birth
preterm birth
Time frame · At birth
Delivery of a fetus at less than 37 and more than 28 weeks gestational age
Eligibility
Participants/eligibility criteria Infertile women who fulfill all of the following inclusion criteria, based on the results and findings of the Atosiban 1 study are eligible for participation: 1. Scheduled for single blastocyst-stage embryo transfer, either in a fresh or frozen transfer cycle; 2. Have a history of one or more episodes of implantation failures in previous embryo transfer cycles; 3. Age between 20 and 40 years (inclusive); 4. Exhibit abnormal uterine peristalsis on transvaginal ultrasound performed on the morning of the scheduled blastocyst transfer, defined as either: high-frequency peristalsis (\>4 contractions per minute), or a negative wave pattern (fundus-to-cervix direction) at any frequency. 5. Each woman could only participate in one transfer cycle. Exclusion criteria 1. Immunologic or endocrine disorders including thyroid dysfunction, antiphospholipid syndrome, hyperprolactinemia and other severe systematic diseases (e.g., hypertension, diabetes, etc.) 2. Uterine malformations (e.g., intrauterine adhesions; unicornuate, bicornuate or septate uterus)； 3. Untreated hydrosalpinx or endometrial polyp； 4. Cycles that included in-vitro maturation or oocyte donation； 5. Prior participation in Atosiban 1 study； 6. Current participation in any other clinical trial； 7. Inability to provide informed consent to the study.
Study locations
China. Showing up to 24 locations stored in the fast local snapshot.
Center for Reproductive Medicine, Northwest Women's and Children's Hospital
Xi'an, Shaanxi, China
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