Frozen embryo transfer. Long-term growth and health of singleton offspring.
Thesis event information
Date and time of the thesis defence
Place of the thesis defence
Auditorium 4, Oulu University Hospital
Topic of the dissertation
Frozen embryo transfer. Long-term growth and health of singleton offspring.
Doctoral candidate
MD Anna Terho
Faculty and unit
University of Oulu Graduate School, Faculty of Medicine, Research Unit of Clinical Medicine
Subject of study
Obstetrics and gynaecology
Opponent
Professor Inger Sundström Poromaa, University of Uppsala
Custos
Professor Hannu Martikainen, University of Oulu
Growth and health of children born after frozen embryo transfer
The studies in this thesis aimed to investigate the foetal, childhood and adolescent growth and health of singleton children born after frozen embryo transfer in the setting of Finnish and Nordic registers and a local child health clinic dataset.
Embryo freezing rates have been on the rise during the past two decades. Embryo freezing enables the use of elective single embryo transfer, reducing the prevalence of multiple gestations, thus improving the perinatal health of children born after assisted reproduction.
Birthweights after frozen compared to fresh embryo transfer were significantly higher starting from gestational week 33 for boys and 34 for girls. The risk of large-for-gestational-age birth weight was almost twofold after frozen compared to fresh embryo transfer and 1.3 –fold after frozen embryo transfer compared to natural conception.
No growth differences were found until 5 years of age between term-born singletons after frozen embryo transfer, fresh embryo transfer and natural conception. Between ages 7 and 18, no significant growth differences were found between girls born after frozen embryo transfer, fresh embryo transfer and natural conception. However, boys born after frozen embryo transfer were taller compared to natural conception and heavier with an increased risk of overweight compared to boys born after fresh embryo transfer and natural conception in the teen years.
Children born after frozen embryo transfer had slightly or moderately increased risks of diagnoses in several main diagnosis chapters, as well as a slightly, but significantly increased need of hospital care compared to naturally conceived children. However, no differences in morbidity were found between children born after frozen and fresh embryo transfer.
In conclusion, the results of these studies provide further evidence of the safety and feasibility of the use of frozen compared to fresh embryo transfer. The increased risk of overweight among boys born after frozen embryo transfer warrants further research.
Embryo freezing rates have been on the rise during the past two decades. Embryo freezing enables the use of elective single embryo transfer, reducing the prevalence of multiple gestations, thus improving the perinatal health of children born after assisted reproduction.
Birthweights after frozen compared to fresh embryo transfer were significantly higher starting from gestational week 33 for boys and 34 for girls. The risk of large-for-gestational-age birth weight was almost twofold after frozen compared to fresh embryo transfer and 1.3 –fold after frozen embryo transfer compared to natural conception.
No growth differences were found until 5 years of age between term-born singletons after frozen embryo transfer, fresh embryo transfer and natural conception. Between ages 7 and 18, no significant growth differences were found between girls born after frozen embryo transfer, fresh embryo transfer and natural conception. However, boys born after frozen embryo transfer were taller compared to natural conception and heavier with an increased risk of overweight compared to boys born after fresh embryo transfer and natural conception in the teen years.
Children born after frozen embryo transfer had slightly or moderately increased risks of diagnoses in several main diagnosis chapters, as well as a slightly, but significantly increased need of hospital care compared to naturally conceived children. However, no differences in morbidity were found between children born after frozen and fresh embryo transfer.
In conclusion, the results of these studies provide further evidence of the safety and feasibility of the use of frozen compared to fresh embryo transfer. The increased risk of overweight among boys born after frozen embryo transfer warrants further research.
Last updated: 23.1.2024