Related Experiment Video
Updated: Jul 16, 2025
Human Blastocyst Biopsy and Vitrification
Published on: July 26, 2019
Assessing obstetric outcomes: A systematic review and meta-analysis comparing fresh, artificial, and natural thaw
Amy Field1, Genia Rozen2,3,4, Joscelyn Gan5
1University of Melbourne, Melbourne, Victoria, Australia.
Background:
The increasing utilisation of in vitro fertilisation (IVF) has prompted significant interest in determining the optimal endometrial environment to increase pregnancy rates and minimise the obstetric complications associated with various embryo transfer strategies.
Aims:
To determine which cycle is associated with increased obstetric complications: fresh embryo transfer (FreshET), natural thaw (NatThawET) or artificial thaw (ArtThawET). Outcomes of interest included: hypertensive disorders of pregnancy (HDP), gestational diabetes (GD), pre-term birth (PTB), post-partum haemorrhage (PPH) and large for gestational age (LGA).
Materials And Methods:
A comprehensive search of MEDLINE, EMBASE, CENTRAL, and PUBMED was conducted from 1947 to May 17, 2022. Two independent reviewers carried out the screening, and data extraction for the following comparisons: ArtThawET vs NatThawET, ArtThawET vs FreshET, and NatThawET vs FreshET. Meta-analysis was conducted using a fixed-effect Mantel-Haenszel model. The quality of the studies was assessed using GRADEpro.
Results:
A total of 23 studies were included in this review. ArtThawET was associated with a significantly increased odds of HDP (odds ratio (OR) 1.76, confidence interval (CI) 1.66-1.86), PTB (OR 1.18, CI 1.13-1.23), PPH (OR 2.61, CI 2.3-2.97) and LGA (OR 1.11, CI 1.07-1.15), compared to NatThawET. ArtThawET was also associated with increased odds of HDP (OR 2.13, CI 1.89-2.4), PPH (OR 3.52, CI 3.06-4.04) and LGA (OR 2.12, CI 1.77-2.56), compared to FreshET. Furthermore, NatThawET demonstrated increased odds of HDP (OR 1.20, CI 1.11-1.29), PPH (OR 1.25, CI 1.14-1.38) and LGA (OR 1.85, CI 1.66-2.07) compared to FreshET.
Conclusion:
When clinically feasible, ArtThawET should be avoided as a first-line option for IVF to reduce the risk of obstetric complications. An adequately powered, multicentre randomised controlled trial is necessary to confirm these findings and investigate the underlying pathophysiology.
More Related Videos
08:28Morphometric Protocol for the Objective Assessment of Blastocyst Behavior During Vitrification and Warming Steps
Published on: February 28, 2019
09:35Modified MicroSecure Vitrification: A Safe, Simple and Highly Effective Cryopreservation Procedure for Human Blastocysts
Published on: March 2, 2017
