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Journal Article•DOI•

Perinatal outcomes of children born after frozen-thawed embryo transfer: a Nordic cohort study from the CoNARTaS group

Ulla-Britt Wennerholm1, Anna-Karina Aaris Henningsen2, Liv Bente Romundstad3, Christina Bergh4, Anja Pinborg2, Rolv Skjærven5, Julie Lyng Forman6, Mika Gissler7, Karl-Gösta Nygren8, Aila Tiitinen9 •
University of Gothenburg1, Copenhagen University Hospital2, Norwegian University of Science and Technology3, Sahlgrenska University Hospital4, University of Bergen5, University of Copenhagen6, National Institutes of Health7, Karolinska Institutet8, Helsinki University Central Hospital9
01 Sep 2013-Human Reproduction (Oxford University Press)-Vol. 28, Iss: 9, pp 2545-2553
TL;DR: Singletons born after FET have a better perinatal outcome compared with singletons Born after fresh IVF and ICSI as regards low birthweight (LBW) and preterm birth (PTB), but a worse per inatal outcomeCompared with children conceived after spontaneous conception.
Abstract: Study questions What are the risks of adverse outcomes in singletons born after frozen-thawed embryo transfer (FET)? Summary answer Singletons born after FET have a better perinatal outcome compared with singletons born after fresh IVF and ICSI as regards low birthweight (LBW) and preterm birth (PTB), but a worse perinatal outcome compared with singletons born after spontaneous conception. What is known already Previous studies have shown a worse perinatal outcome in children born after IVF in general compared with children born after spontaneous conception. In singletons born after FET, a lower rate of PTB and LBW and a higher rate of large for gestational age (LGA) compared with singletons born after fresh IVF have been shown. Study design A retrospective Nordic population-based cohort study of all singletons conceived after FET in Denmark, Norway and Sweden until December 2007 was performed. Participants/materials, setting and methods Singletons born after FET (n = 6647) were compared with a control group of singletons born after fresh IVF and ICSI (n = 42 242) and singletons born after spontaneous conception (n = 288 542). Data on perinatal outcomes were obtained by linkage to the national Medical Birth Registries. Odds ratios were calculated for several perinatal outcomes and adjustments were made for maternal age, parity, year of birth, offspring sex and country of origin. Main results and the role of chance Singletons born after FET had a lower risk of LBW (adjusted odds ratio (aOR) 0.81, 95% confidence interval (CI) 0.71-0.91), PTB (aOR 0.84, 95% CI 0.76-0.92), very PTB (VPTB; aOR 0.79, 95% CI 0.66-0.95) and small for gestational age (SGA; aOR 0.72, 95% CI 0.62-0.83), but a higher risk of post-term birth (aOR 1.40, 95% CI 1.27-1.55), LGA (aOR 1.45, 95% CI 1.27-1.64), macrosomia (aOR 1.58, 95% CI 1.39-1.80) and perinatal mortality (aOR 1.49, 95% CI 1.07-2.07) compared with singletons born after fresh IVF and ICSI. Compared with children conceived after spontaneous conception, singletons born after FET had a higher risk of LBW (aOR 1.27, 95% CI 1.13-1.43), very LBW (aOR 1.69, 95% CI 1.33-2.15), PTB (aOR 1.49, 95% CI 1.35-1.63), VPTB (aOR 2.68, 95% CI 2.24-3.22), SGA (aOR 1.18, 95% CI 1.03-1.35), LGA (aOR 1.29, 95% CI 1.15-1.45), macrosomia (aOR 1.29, 95% CI 1.15-1.45) and perinatal (aOR 1.39, 95% CI 1.03-1.87) neonatal (aOR 1.87, 95% CI 1.23-2.84) and infant mortality (aOR 1.92, 95% CI 1.36-2.72). When analyzing trends over time, the risk of being born LGA increased over time for singletons born after FET compared with singletons born after fresh IVF and ICSI (P = 0.04). Limitations, reasons for caution As in all observational studies, the possible role of residual confounding factors and bias should be considered. In this study, we were not able to control for confounding factors, such as BMI, smoking and reason for, or length of, infertility. Wider implications of the findings Perinatal outcomes in this large population-based cohort of children born after FET from three Nordic countries compared with fresh IVF and ICSI and spontaneous conception were in agreement with the literature.
Citations
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Journal Article•DOI•
Fresh versus Frozen Embryos for Infertility in the Polycystic Ovary Syndrome

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Zi-Jiang Chen1, Zi-Jiang Chen2, Yuhua Shi3, Yun Sun1, Bo Zhang, Xiaoyan Liang4, Yunxia Cao5, Jing Yang6, Jiayin Liu7, Daimin Wei2, Ning Weng, Li Feng Tian, Cuifang Hao8, Dongzi Yang4, Feng Zhou9, Juanzi Shi, Yongle Xu7, Jing Li2, Junhao Yan2, Yingying Qin2, Han Zhao2, Heping Zhang3, Richard S. Legro •
Shanghai Jiao Tong University1, Shandong University2, Yale University3, Sun Yat-sen University4, Anhui Medical University5, Wuhan University6, Nanjing Medical University7, Yuhuangding Hospital8, Zhejiang University9
10 Aug 2016-The New England Journal of Medicine
TL;DR: Among infertile women with the polycystic ovary syndrome, frozen-embryo transfer was associated with a higher rate of live birth, a lower risk of the ovarian hyperstimulation syndrome, and a higher risk of preeclampsia after the first transfer than was fresh-embyo transfer.
Abstract: BackgroundThe transfer of fresh embryos is generally preferred over the transfer of frozen embryos for in vitro fertilization (IVF), but some evidence suggests that frozen-embryo transfer may improve the live-birth rate and lower the rates of the ovarian hyperstimulation syndrome and pregnancy complications in women with the polycystic ovary syndrome. MethodsIn this multicenter trial, we randomly assigned 1508 infertile women with the polycystic ovary syndrome who were undergoing their first IVF cycle to undergo either fresh-embryo transfer or embryo cryopreservation followed by frozen-embryo transfer. After 3 days of embryo development, women underwent the transfer of up to two fresh or frozen embryos. The primary outcome was a live birth after the first embryo transfer. ResultsFrozen-embryo transfer resulted in a higher frequency of live birth after the first transfer than did fresh-embryo transfer (49.3% vs. 42.0%), for a rate ratio of 1.17 (95% confidence interval [CI], 1.05 to 1.31; P=0.004). Women w...

521 citations

Journal Article•DOI•
ART in Europe, 2014: results generated from European registries by ESHRE: The European IVF-monitoring Consortium (EIM) for the European Society of Human Reproduction and Embryology (ESHRE).

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Christian De Geyter, Carlos Calhaz-Jorge, M. Kupka, Christine Wyns1, Edgar Mocanu2, Tatiana Motrenko, Guilia Scaravelli3, Jesper M. J. Smeenk, Snezana Vidakovic, Veerle Goossens •
Cliniques Universitaires Saint-Luc1, Rotunda Hospital2, Istituto Superiore di Sanità3
01 Sep 2018-Human Reproduction
TL;DR: A continuing expansion of both treatment numbers in Europe and more variability in treatment modalities resulting in a rising contribution to the birth rates in most participating countries is shown.
Abstract: Study question: What are the European trends and developments in ART and IUI in 2014 as compared to previous years? Summary answer: The 18th ESHRE report on ART shows a continuing expansion of both treatment numbers in Europe and more variability in treatment modalities resulting in a rising contribution to the birth rates in most participating countries. What is known already: Since 1997, ART data generated by national registries have been collected, analysed by the European IVF-monitoring (EIM) Consortium and reported in 17 manuscripts published in Human Reproduction. Study design, size, duration: Continuous collection of European data by the EIM for ESHRE. The data for treatments performed in 2014 between 1 January and 31 December in 39 European countries were provided by national registries or on a voluntary basis by clinics or professional societies. Participants/materials, setting, methods: From 39 countries and 1279 institutions offering ART services, a total of 776 556 treatment cycles, involving 146 148 with IVF, 362 285 with ICSI, 192 027 with frozen embryo replacement (FER), 15 894 with PGT, 56 516 with egg donation (ED), 292 with IVM and 3404 with frozen oocyte replacement (FOR) were reported. European data on IUI using husband/partner's semen (IUI-H) and donor semen (IUI-D) were reported from 1364 institutions offering IUI in 26 countries and 21 countries, respectively. A total of 120 789 treatments with IUI-H and 49 163 treatments with IUI-D were included. Main results and the role of chance: In 14 countries (17 in 2013), where all institutions contributed to their respective national registers, a total of 291 235 treatment cycles were performed in a population of ~208 million inhabitants, corresponding to 1925 cycles per million inhabitants (range: 423-2978 per million inhabitants). After treatment with IVF the clinical pregnancy rates (PR) per aspiration and per transfer were marginally higher in 2014 than in 2013, at 29.9 and 35.8% versus 29.6 and 34.5%, respectively. After treatment with ICSI the PR per aspiration and per transfer were also higher than those achieved in 2013 (28.4 and 35.0% versus 27.8 and 32.9%, respectively). After FER with own embryos the PR continued to rise, from 27.0% in 2013 to 27.6% in 2014. After ED a similar trend was observed with PR reaching 50.3% per fresh transfer (49.8% in 2013) and 48.7% for FOR (46.4% in 2013). The delivery rates (DR) after IUI remained stable at 8.5% after IUI-H (8.6% in 2013) and at 11.6% after IUI-D (11.1% in 2013). In IVF and ICSI together, 1, 2, 3 and ≥4 embryos were transferred in 34.9, 54.5, 9.9 and in 0.7% of all treatments, respectively (corresponding to 31.4%, 56.3, 11.5% and 1% in 2013). This evolution in embryo transfer strategy in both IVF and ICSI resulted in a singleton, twin and triplet DR of 82.5, 17.0 and 0.5%, respectively (compared to 82.0, 17.5 and 0.5%, respectively, in 2013). Treatments with FER in 2014 resulted in a twin and triplet DR of 12.4 and 0.3%, respectively (versus 12.5 and 0.3% in 2013). Twin and triplet DR after IUI were 9.5 and 0.3%, respectively, after IUI-H (in 2013:9.5 and 0.6%) and 7.7 and 0.3% after IUI-D (in 2013: 7.5 and 0.3%). Limitation, reasons for caution: The method of data collection and reporting varies among European countries. The EIM receives aggregated data from various countries with variable levels of completeness. Registries from a number of countries have failed to provide adequate data about the number of initiated cycles and deliveries. As long as incomplete data are provided, the results should be interpreted with caution. Wider implications of the findings: The 18th ESHRE report on ART shows a continuing expansion of treatment numbers in Europe. The number of treatments reported, the variability in treatment modalities and the rising contribution to the birth rates in most participating countries point towards the increasing impact of ART on reproduction in Europe. Being the largest data collection on ART, the report gives detailed information about ongoing developments in the field. Study funding/competing interest(s): The study has no external funding and all costs are covered by ESHRE. There are no competing interests.

409 citations

Cites background from "Perinatal outcomes of children born..."

  • ...Singleton pregnancies after ART are prone to a higher risk of obstetric complications, including prematurity (Wennerholm et al., 2013; Sunkara et al., 2015; Qin et al., 2016), but pregnancy outcome does not depend on the number of retrieved oocytes (Magnusson et al....

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Journal Article•
Assisted reproductive technology.

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Sauer Mv
01 Aug 1994-Western Journal of Medicine
TL;DR: Assisted reproductive technology (ART) is the technology used to achieve pregnancy in procedures such as fertility medication, artificial insemination, in vitro fertilization and surrogacy.
Abstract: Assisted reproductive technology (ART) is the technology used to achieve pregnancy in procedures such as fertility medication, artificial insemination, in vitro fertilization and surrogacy. It is reproductive technology used primarily for infertility treatments, and is also known as fertility treatment. It mainly belongs to the field of reproductive endocrinology and infertility, and may also include intracytoplasmic sperm injection (ICSI) and cryopreservation. Some forms of ART are also used with regard to fertile couples for genetic reasons (preimplantation genetic diagnosis). ART is also used for couples who are discordant for certain communicable diseases; for example, HIV to reduce the risk of infection when a pregnancy is desired.

357 citations

Journal Article•DOI•
Is frozen embryo transfer better for mothers and babies? Can cumulative meta-analysis provide a definitive answer?

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Abha Maheshwari, Shilpi Pandey1, Edwin Amalraj Raja2, Ashalatha Shetty, Mark Hamilton, Siladitya Bhattacharya2 •
University of Nottingham1, University of Aberdeen2
01 Jan 2018-Human Reproduction Update
TL;DR: The results of this cumulative meta-analysis of obstetric and perinatal complications in singleton pregnancies following the transfer of frozen thawed and fresh embryos generated through in-vitro fertilisation confirm that the decreased risks of small for gestational age, low birth weight and preterm delivery and increased risks of large for Gestational age and high birth weight associated with pregnancies conceived from frozen embryos have been consistent in terms of direction and magnitude of effect over several years.
Abstract: BACKGROUND Initial observational studies and a systematic review published 5 years ago have suggested that obstetric and perinatal outcomes are better in offspring conceived following frozen rather than fresh embryo transfers, with reduced risks of preterm birth, small for gestational age, low birth weight and pre-eclampsia. More recent primary studies are beginning to challenge some of these findings. We therefore conducted an updated systematic review and cumulative meta-analysis to examine if these results have remained consistent over time. OBJECTIVE AND RATIONALE The aim of this study was to perform a systematic review and cumulative meta-analysis (trend with time) of obstetric and perinatal complications in singleton pregnancies following the transfer of frozen thawed and fresh embryos generated through in-vitro fertilisation. SEARCH METHODS Data Sources from Medline, EMBASE, Cochrane Central Register of Clinical Trials DARE and CINAHL (1984–2016) were searched using appropriate key words. Observational and randomised studies comparing obstetric and perinatal outcomes in singleton pregnancies conceived through IVF using either fresh or frozen thawed embryos. Two independent reviewers extracted data in 2 × 2 tables and assessed the methodological quality of the relevant studies using CASP scoring. Both aggregated as well as cumulative meta-analysis was done using STATA. OUTCOMES Twenty-six studies met the inclusion criteria. Singleton babies conceived from frozen thawed embryos were at lower relative risk (RR) of preterm delivery (0.90; 95% CI 0.84–0.97) low birth weight (0.72; 95% CI 0.67–0.77) and small for gestational age (0.61; 95% CI 0.56–0.67) compared to those conceived from fresh embryo transfers, but faced an increased risk (RR) of hypertensive disorders of pregnancy (1.29; 95% CI 1.07–1.56) large for gestational age (1.54; 95% CI 1.48–1.61) and high birth weight (1.85; 95% CI 1.46–2.33). There was no difference in the risk of congenital anomalies and perinatal mortality between the two groups. The direction and magnitude of effect for these outcomes have remained virtually unchanged over time while the degree of precision has improved with the addition of data from newer studies. WIDER IMPLICATIONS The results of this cumulative meta-analysis confirm that the decreased risks of small for gestational age, low birth weight and preterm delivery and increased risks of large for gestational age and high birth weight associated with pregnancies conceived from frozen embryos have been consistent in terms of direction and magnitude of effect over several years, with increasing precision around the point estimates. Replication in a number of different populations has provided external validity for the results, for outcomes of birth weight and preterm delivery. Meanwhile, caution should be exercised about embarking on a policy of electively freezing all embryos in IVF as there are increased risks for large for gestational age babies and hypertensive disorders of pregnancy. Therefore, elective freezing should ideally be undertaken in specific cases such as ovarian hyperstimulation syndrome, fertility preservation or in the context of randomised trials.

338 citations

Cites background or methods from "Perinatal outcomes of children born..."

  • ...This was defined as birth weight greater than 2 standard deviations of the mean for that gestation (Pelkonen et al., 2010; Wennerholm et al., 2013; Ishihara et al., 2014; Pinborg et al., 2014) or more than the 90th centile (Kato et al., 2012; Li et al., 2014) or birth weight more than 22% of…...

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  • ...…and Tremellen, 2013; Li et al., 2014), beyond 21 weeks (Ishihara et al., 2014); beyond 22 weeks (Pelkonen et al., 2010, 2014; Kato et al., 2012; Wennerholm et al., 2013; Opdahl et al., 2015) and beyond 28 weeks (Wennerholm et al., 1997; Wikland et al., 2010; Liu et al., 2013) and only live…...

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  • ..., 2014); beyond 22 weeks (Pelkonen et al., 2010, 2014; Kato et al., 2012; Wennerholm et al., 2013; Opdahl et al., 2015) and beyond 28 weeks (Wennerholm et al....

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  • ...…7 days of life (Kato et al., 2012); death after 28 weeks of gestation up to the first 7 days of life (Pelkonen et al., 2010, Wikland et al., 2010, Liu et al., 2013, Wennerholm et al., 2013, Li et al., 2014); or death after 20 weeks, later terminations and all neonatal deaths (Shih et al., 2008)....

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  • ...Data were collected after medical records review Controls were matched for age and parity 10.5/11 Wennerholm et al. (2013) Reterospective Matched cohort study Retrospective Nordic population-based cohort study of all singletons conceived after FET in Denmark, Norway and Sweden until December 2007…...

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Journal Article•DOI•
Assisted reproductive technology and the risk of pregnancy-related complications and adverse pregnancy outcomes in singleton pregnancies: a meta-analysis of cohort studies

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Jiabi Qin1, Xiaoying Liu1, Xiaoqi Sheng, Hua Wang, Shiyou Gao •
Central South University1
01 Jan 2016-Fertility and Sterility
TL;DR: The ART singleton pregnancies are associated with higher risks of adverse obstetric outcomes and Obstetricians should manage these pregnancies as high risk.

317 citations

References
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Journal Article•DOI•
Intrauterine growth curves based on ultrasonically estimated foetal weights.

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Karel Marsal1, P H Persson1, T Larsen2, Håkan Lilja3, Anders Selbing4, B Sultan3 •
Lund University1, University of Copenhagen2, University of Gothenburg3, Linköping University4
01 Jul 1996-Acta Paediatrica
TL;DR: New growth curves are presented based on data from four Scandinavian centres for 759 ultrasonically estimated foetal weights in 86 uncomplicated pregnancies, revealing better the true distribution of SGA foetuses and neonates and are suggested for use in perinatological practice.
Abstract: Available standard intrauterine growth curves based on birthweights underestimate foetal growth in preterm period. New growth curves are presented based on data from four Scandinavian centres for 759 ultrasonically estimated foetal weights in 86 uncomplicated pregnancies. Mean weight of boys exceeded that of girls by 2-3%. A uniform SD value of 12% of the mean weight was adopted for the standard curves as the true SD varied non-systematically between 9.1 and 12.4%. Applied to an unselected population of 8663 singleton births, before 210 days of gestation, 32% of birthweights were classified as small-for-gestational age (SGA; i.e. below mean - 2 SD); the corresponding figures were 11.1% for gestational ages between 210 and 258 days, and 2.6% for ages of 259 days or longer. The new growth curves reveal better the true distribution of SGA foetuses and neonates, and are suggested for use in perinatological practice.

1,647 citations

"Perinatal outcomes of children born..." refers methods in this paper

  • ...Marsal’s formula was used to calculate SGA and LGA, which was defined as a birthweight of less than 22 standard deviations (SD) or greater than +2SD, respectively, according to the reference value with adjustment for gestational age and sex (Marsal et al., 1996)....

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  • ...We have used Marsal’s formula to calculate LGA, which defines a birthweight of greater than +2SD, according to the reference value with adjustment for gestational age and gender (Marsal et al., 1996)....

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Journal Article•DOI•
Large offspring syndrome in cattle and sheep.

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Lorraine E. Young1, Kevin D. Sinclair, Ian Wilmut1•
The Roslin Institute1
01 Sep 1998-Reviews of Reproduction
TL;DR: Four different situations have been identified that result in the large offspring syndrome: in vitro embryo culture, asynchronous embryo transfer into an advanced uterine environment, nuclear transfer and maternal exposure to excessively high urea diets.
Abstract: Bovine and ovine embryos exposed to a variety of unusual environments prior to the blastocyst stage have resulted in the development of unusually large offspring which can also exhibit a number of organ defects. In these animals, the increased incidence of difficult parturition and of fetal and neonatal losses has limited the large-scale use of in vitro embryo production technologies commonly used in humans and other species. Four different situations have been identified that result in the syndrome: in vitro embryo culture, asynchronous embryo transfer into an advanced uterine environment, nuclear transfer and maternal exposure to excessively high urea diets. However, programming of the syndrome by all of these situations is unpredictable and not all of the symptoms described have been observed universally. Neither the environmental factors inducing the large offspring syndrome nor the mechanisms of perturbation occurring in the early embryo and manifesting themselves in the fetus have been identified.

912 citations

"Perinatal outcomes of children born..." refers background in this paper

  • ...For example, in vitro culture methods and composition of culture media may induce large offspring syndrome in ruminants (Young et al., 1998)....

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Journal Article•DOI•
Why do singletons conceived after assisted reproduction technology have adverse perinatal outcome? Systematic review and meta-analysis

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Anja Pinborg1, U.B. Wennerholm2, L.B. Romundstad3, Annika Loft1, Kristiina Aittomäki4, Viveca Söderström-Anttila, K.G. Nygren5, J. Hazekamp, Christina Bergh2 •
Copenhagen University Hospital1, Sahlgrenska University Hospital2, Norwegian University of Science and Technology3, Helsinki University Central Hospital4, Karolinska Institutet5
01 Mar 2013-Human Reproduction Update
TL;DR: Subfertility is a major risk factor for adverse perinatal outcome in ART singletons, however, even in the same mother an ART singleton has a poorer outcome than the non-ART sibling; hence, factors related to the hormone stimulation and/or IVF methods per se also may play a part.
Abstract: Background Assisted reproduction technology (ART) is used worldwide, at increasing rates, and data show that some adverse outcomes occur more frequently than following spontaneous conception (SC). Possible explanatory factors for the well-known adverse perinatal outcome in ART singletons were evaluated. Methods PubMed and Cochrane databases from 1982 to 2012 were searched. Studies using donor or frozen oocytes were excluded, as well as those with no control group or including Results The search returned 1255 articles and 65 of these met the inclusion criteria. The following were identified as predictors for PTB in singletons: SC in couples with time to pregnancy (TTP) > 1 year versus SC singletons in couples with TTP ≤ 1 year [adjusted odds ratio (AOR) 1.35, 95% confidence interval (CI) 1.22, 1.50]; IVF/ICSI versus SC singletons from subfertile couples (TTP > 1 year; AOR 1.55, 95% CI 1.30, 1.85); conception after ovulation induction and/or intrauterine insemination versus SC singletons where TTP ≤ 1 year (AOR 1.45, 95% CI 1.21, 1.74); IVF/ICSI singletons versus their non-ART singleton siblings (AOR 1.27, 95% CI 1.08, 1.49). The risk of PTB in singletons with a 'vanishing co-twin' versus from a single gestation was AOR of 1.73 (95% CI 1.54, 1.94) in the narrative data. ICSI versus IVF (AOR 0.80, 95% CI 0.69-0.93), and frozen embryo transfer versus fresh embryo transfer (AOR 0.85, 95% CI 0.76, 0.94) were associated with a lower risk of PTB. Conclusions Subfertility is a major risk factor for adverse perinatal outcome in ART singletons, however, even in the same mother an ART singleton has a poorer outcome than the non-ART sibling; hence, factors related to the hormone stimulation and/or IVF methods per se also may play a part. Further research is required into mechanisms of epigenetic modification in human embryos and the effects of cryopreservation on this, whether milder ovarian stimulation regimens can improve embryo quality and endometrial conditions, and whether longer culture times for embryos has a negative influence on the perinatal outcome.

566 citations

Journal Article•DOI•
Evidence of impaired endometrial receptivity after ovarian stimulation for in vitro fertilization: a prospective randomized trial comparing fresh and frozen-thawed embryo transfer in normal responders

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Bruce S. Shapiro1, Said T. Daneshmand1, Forest C. Garner1, Martha Aguirre, C. Hudson, S. Thomas •
University of Nevada, Reno1
01 Aug 2011-Fertility and Sterility
TL;DR: The clinical pregnancy rate per transfer was significantly greater in the cryopreservation group than in the fresh group, which strongly suggest impaired endometrial receptivity in fresh ET cycles after ovarian stimulation, when compared with FET cycles with artificialendometrial preparation.

555 citations

"Perinatal outcomes of children born..." refers background in this paper

  • ...ORIGINAL ARTICLE Reproductive epidemiology Perinatal outcomes of children born after frozen-thawed embryo transfer: a Nordic cohort study from the CoNARTaS group Ulla-Britt Wennerholm1,†*, Anna-Karina Aaris Henningsen2,†, Liv Bente Romundstad3,4, Christina Bergh1, Anja Pinborg2, Rolv Skjaerven5,6, Julie Forman7, Mika Gissler8,9, Karl Gösta Nygren10, and Aila Tiitinen11 1Department of Obstetrics and Gynaecology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Sahlgrenska University Hospital, East SE-416 85, Gothenburg, Sweden, 2Fertility Clinic, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark, 3Department of Obstetrics and Gynecology, Fertility Clinic, St Olav’s University Hospital, Trondheim, Norway, 4Department of Public Health, Norwegian University of Science and Technology, Trondheim, Norway, 5Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway, 6Medical Birth Register of Norway, National Institute of Public Health, Bergen, Norway, 7Department of Biostatistics, University of Copenhagen, Copenhagen, Denmark, 8THL, National Institute for Health and Welfare, Helsinki, Finland, 9Nordic School of Public Health, Gothenburg, Sweden, 10Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden and 11Department of Obstetrics and Gynecology, Helsinki University Central Hospital, Helsinki, Finland *Correspondence address....

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  • ...…Karl Gösta Nygren10, and Aila Tiitinen11 1Department of Obstetrics and Gynaecology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Sahlgrenska University Hospital, East SE-416 85, Gothenburg, Sweden, 2Fertility Clinic, Rigshospitalet, Copenhagen University…...

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  • ...Results from randomized trials (Aflatoonian et al., 2010; Shapiro et al., 2011, 2012) and a meta-analysis (Roque et al., 2013) have indicated a significantly higher clinical pregnancy rate after cryopreservation compared with fresh cycles....

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Journal Article•DOI•
Fresh embryo transfer versus frozen embryo transfer in in vitro fertilization cycles: a systematic review and meta-analysis.

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Matheus Roque1, K. Lattes1, Sandra Serra1, Ivan Solà2, Selmo Geber3, Ramon Carreras1, Miguel A. Checa1 •
Autonomous University of Barcelona1, Cochrane Collaboration2, Universidade Federal de Minas Gerais3
01 Jan 2013-Fertility and Sterility
TL;DR: There is evidence that IVF outcomes may be improved by performing FET compared with fresh embryo transfer, and this could be explained by a better embryo-endometrium synchrony achieved with endometrium preparation cycles.

450 citations

"Perinatal outcomes of children born..." refers background in this paper

  • ..., 2011, 2012) and a meta-analysis (Roque et al., 2013) have indicated a significantly higher clinical pregnancy rate after cryopreservation compared with fresh cycles....

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  • ...The pregnancy and live birth rates after cryopreservation have increased and are now described to be close to or even higher (Roque et al., 2013) compared with fresh cycles....

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  • ...Results from randomized trials (Aflatoonian et al., 2010; Shapiro et al., 2011, 2012) and a meta-analysis (Roque et al., 2013) have indicated a significantly higher clinical pregnancy rate after cryopreservation compared with fresh cycles....

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Related Papers (5)
Impact of frozen-thawed single-blastocyst transfer on maternal and neonatal outcome: an analysis of 277,042 single-embryo transfer cycles from 2008 to 2010 in Japan

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01 Jan 2014-Fertility and Sterility
Osamu Ishihara, Ryuichiro Araki, Akira Kuwahara, Atsuo Itakura, Hidekazu Saito, G. David Adamson 
Obstetric and perinatal outcomes in singleton pregnancies resulting from the transfer of frozen thawed versus fresh embryos generated through in vitro fertilization treatment: a systematic review and meta-analysis

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01 Aug 2012-Fertility and Sterility
Abha Maheshwari, Shilpi Pandey, Ashalatha Shetty, Mark Hamilton, Siladitya Bhattacharya 
Why do singletons conceived after assisted reproduction technology have adverse perinatal outcome? Systematic review and meta-analysis

[...]

01 Mar 2013-Human Reproduction Update
Anja Pinborg, U.B. Wennerholm, L.B. Romundstad, Annika Loft, Kristiina Aittomäki, Viveca Söderström-Anttila, K.G. Nygren, J. Hazekamp, Christina Bergh 
Fresh embryo transfer versus frozen embryo transfer in in vitro fertilization cycles: a systematic review and meta-analysis.

[...]

01 Jan 2013-Fertility and Sterility
Matheus Roque, K. Lattes, Sandra Serra, Ivan Solà, Selmo Geber, Ramon Carreras, Miguel A. Checa 
Evidence of impaired endometrial receptivity after ovarian stimulation for in vitro fertilization: a prospective randomized trial comparing fresh and frozen-thawed embryo transfer in normal responders

[...]

01 Aug 2011-Fertility and Sterility
Bruce S. Shapiro, Said T. Daneshmand, Forest C. Garner, Martha Aguirre, C. Hudson, S. Thomas