The multi-step thawing protocol with a reduction of non-permeable cryoprotectant concentrations to reduce osmotic shock caused by the rapid influx of water. Recent studies have shown that a simplified warming protocol by only a thawing solution gave a comparable survival rate but increased pregnancy rate, reduced patients' waiting time, and decreased the workload of embryologists.
Nowadays, vitrification is the gold standard method in freezing human embryos, using different commercial brands of ready-to-use kits. Removing cytotoxic cryoprotectants and rehydration to prevent osmotic shock has been a fundamental principle in cryobiology. This minimized damage during the vitrification/thawing (V/T) process. However, the entire process is time-consuming and labor-intensive in the IVF laboratory. Especially, some laboratories have difficulty ordering the same brand of medium for V/T kits. Because of the long period of cryopreserved embryos, it may be that embryos were vitrified and warmed with different kits with a potentially different kind and concentrations of cryoprotective agents. Recently, the combinations of the two different V/T commercial kits have shown comparable survival, blastulation, and implantation rates in both own and donor oocyte cycles. Additionally, there remains an opportunity and a necessity to continue improving the warming protocol. The key factors for thawing require a fast warming rate, a gradually decreasing concentration of intracellular cryoprotectant, and embryologist skills to secure the survival rate. Based on previous work, one option would be shortening the time necessary to rehydrate. A study by Seki and Mazur has shown that embryo survival is almost entirely dependent on the warming rate rather than the extracellular cryoprotectant concentration used. A recent study by Liebermann showed that simplifying warming procedures in one step by using 1M sucrose only is possible with an encouragingly higher ongoing pregnancy rate and comparable clinical outcomes when compared to the same conventional multi-step warming protocol, showing a significantly lower miscarriage rate (4.0% vs. 7.6%). These results lead to a faster, safer, and more cost-effective procedure. This study aims to investigate the effectiveness and safety of a new combination of V/W solutions-single and multi-step thawing protocol- on live birth rate (LBR), as well as embryo transfer, obstetric, and neonatal outcomes.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Potentially eligible patients' vitrified blastocysts will be thawed by a single-step thawing protocol. For the warming phase, vitrified blastocysts are exposed to the thawing solution of a commercial embryo thawing kit (Irvine Scientific Inc., USA) at 37°C for one minute. Immediately following this, embryos will be rinsed in a 35mm diameter dish of 2ml of pre-equilibrated thawing solution before being placed in culture media in the incubator for at least 2 hours before transfer.
For the MS protocol, thawing kits were equilibrated overnight in a 37°C incubator. Warming procedures utilized the kits (Cryotech RtU, Japan). To remove the cryoprotectants, blastocysts were warmed, and cryoprotectants were diluted in a three-step process. The warming process starts with the exposure of blastocysts to thaw solution (TS) with 1M trehalose for one minute at 37°C. Subsequently, the blastocyst will be transferred to a second well containing a dilution solution (DS) of 0.5M trehalose for a two-minute rinse at room temperature. This is followed by two additional three-minute and 30-second rinses in the wash solution (WS) at room temperature. The timeline for standard warming of blastocysts requires a total of 6.5 min. After thawing, embryo will be placed in the incubator at least 2 hours before transfer.
My Duc Hospital
Ho Chi Minh City, City, Vietnam
RECRUITINGLive birth rate
Live birth is defined as the complete expulsion or extraction from a woman of a product of fertilization, after 22 completed weeks of gestational age; which, after such separation, breathes or shows any other evidence of life, such as heart beat, umbilical cord pulsation or definite movement of voluntary muscles, irrespective of whether the umbilical cord has been cut or the placenta is attached. A birth weight of 500 grams or more can be used if gestational age is unknown
Time frame: At 22 weeks of gestation
Survival rate
The survival rate by the presence of blastocoel re-expansion before embryo transfer.
Time frame: At least 2 hours after thawing.
Cancellation rate
Cancellation due to: The blastocyst cells are lysed after thawing.
Time frame: Any day during endometrium preparation days before embryo transfer.
Positive pregnancy test
Serum ß-hCG ≥25mIU/mL
Time frame: At 2 weeks after embryo placement
Implantation rate
The implantation rate is explained as the number of gestational sacs per number of embryos transferred
Time frame: At 3 weeks after embryo placement
Clinical pregnancy
diagnosed by ultrasonographic visualization of one or more gestational sacs or definitive clinical signs of pregnancy at 6 weeks or more after the onset of the last menstrual period. In addition to intra-uterine pregnancy, it includes a clinically documented ectopic pregnancy.
Time frame: At 5 weeks after embryo placement
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.
Purpose
TREATMENT
Masking
NONE
Enrollment
816
Ectopic pregnancy
A pregnancy outside the uterine cavity, diagnosed by ultrasound, surgical visualisation, or histopathology
Time frame: At 7 weeks of gestation
Ongoing pregnancy
Having at least one gestational sac on ultrasound at 12 weeks' gestation with heart beat activity
Time frame: At 10 weeks after embryo placement
Miscarriage
The spontaneous loss of an intra-uterine pregnancy before 22 completed weeks of gestational age
Time frame: before 22 completed weeks of gestational age
Preterm delivery
Multiple definitions, defined as delivery at \<24, \<28, \<32, \<37 completed weeks
Time frame: At 22, 28, 32 weeks and 37 weeks of gestation
Major congenital abnormalities
Structural or functional disorders that occur during intra-uterine life and can be identified prenatally, at birth or later in life. Congenital anomalies can be caused by single gene defects, chromosomal disorders, multifactorial inheritance, environmental teratogens and micronutrient deficiencies. The time of identification should be reported. Any congenital anomaly will be included as followed definition of congenital abnormalities in Surveillance of Congenital Anomalies by Division of Birth Defects and Developmental Disabilities, NCBDDD, Centers for Disease Control and Prevention (2020).
Time frame: At birth
Birth weight
Weight of singletons and twins
Time frame: At the time of delivery
Low birth weight
Weight \< 2500 gm at birth
Time frame: At the time of delivery
Very low birth weight
Weight \< 1500 gm at birth
Time frame: At the time of delivery
High birth weight
Weight over than 4.500 g for women with diabetes, and a threshold of 5.000 g for women without diabetes
Time frame: At the time of delivery
Admission to NICU
The admittance of the newborn to NICU
Time frame: At birth
Multiple pregnancy
≥2 gestational sac at early pregnancy ultrasound
Time frame: At 6 to 8 weeks' gestation
Multiple delivery
Birth of more than one baby beyond 22 weeks
Time frame: At 22 weeks' gestation
Still birth
The death of a fetus prior to the complete expulsion or extraction from its mother after 20 completed weeks of gestational age. The death is determined by the fact that, after such separation, the fetus does not breathe or show any other evidence of life, such as heartbeat, umbilical cord pulsation, or definite movement of voluntary muscles.
Time frame: At 20 weeks' gestation
Neonatal mortality
Death of a live-born baby within 28 days of birth. This can be divided into early neonatal mortality, if death occurs in the first seven days after birth, and late neonatal if death occurs between eight and 28 days after delivery
Time frame: within 28 days of birth
Direct costs to live birth
Total direct cost to have a live birth after embryo transfer. Direct cost include medical consultations, ovulation stimulation drugs, laboratory and embryology services, ultrasound scanning, medical procedures such as oocyte retrieval and embryo transfer, hospital charges, nursing and counselling services and administrative and overhead charges. Cost data will be collected for a supplementary analysis and will be reported in a separated paper.
Time frame: At the time of delivery