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

Maheshwari, Abha; Pandey, Shilpi; Shetty, Ashalatha; Hamilton, Mark; Bhattacharya, Siladitya

doi:10.1016/j.fertnstert.2012.05.019

Cited by 466 publications

(366 citation statements)

References 27 publications

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“…In fresh donor cycles, recipients have hormone levels more comparable to those in a natural conception cycle, which may in part explain the improved rates of implantation, clinical pregnancy, and live births [38], as well as lower rates of LBW, SGA [8], and preterm birth [5]. Results of clinical studies and meta-analyses of IVF pregnancies indicate the risks for SGA, preterm birth, LBW, antepartum hemorrhage, and perinatal mortality are significantly reduced with frozen compared to those with fresh embryo transfers [2,[39][40][41][42]. The risk of prenatal bleeding, placental complications, and postpartum hemorrhage has been shown to be higher in both subfertile and IVF pregnancies compared to those conceived spontaneously [43][44][45].…”

Section: Discussionmentioning

confidence: 99%

Increased risk of large-for-gestational age birthweight in singleton siblings conceived with in vitro fertilization in frozen versus fresh cycles

Luke

Brown

Wantman³

et al. 2016

J Assist Reprod Genet

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Background Children born from fresh in vitro fertilization (IVF) cycles are at greater risk of being born smaller and earlier, even when limited to singletons; those born from frozen cycles have an increased risk of large-for-gestational age (LGA) birthweight (z-score ≥1.28). This analysis sought to overcome limitations in other studies by using pairs of siblings, and accounting for prior cycle outcomes, maternal characteristics, and embryo state and stage. LGAwas 9.2-9.8 and 14.2-15.4% in 1st and 2nd births in fresh cycles, and 13.1-15.8 and 20.8-21.0% in 1st and 2nd births in frozen cycles. The risk of LGAwas increased in frozen cycles (1st births, adjusted odds ratios (AOR) 1.74, 95% CI 1.45, 2.08; and in 2nd births when the 1st birth was not LGA, AOR 1.70, 95% CI 1.46, 1.98 for fresh/frozen and 1.40, 1.11, 1.78 for frozen/frozen). Conclusions Our results with siblings indicate that frozen embryo state is associated with an increased risk for LGA. The implications of these findings for childhood health and risk of obesity are unclear, and warrant further investigation.

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Section: Discussionmentioning

confidence: 99%

Increased risk of large-for-gestational age birthweight in singleton siblings conceived with in vitro fertilization in frozen versus fresh cycles

Luke

Brown

Wantman³

et al. 2016

J Assist Reprod Genet

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“…The influences of the culture media [21][22][23], culture period [24,25], hormonal protocols [26], and infertility [12,14,27] on the IVF singleton birth weight have already been considered. There are several studies confirming that IVF placentas differ from spontaneous placentas in their size, shape, weight, and abnormality rate [3,6,7,[28][29][30][31], and that placentation following FET differ from the placentation following fresh ET [3,6,7,13] In this study, we analyzed the connection of IVF procedure type and maternal background factors to LGA risk.…”

Section: Introductionmentioning

confidence: 99%

Independent factors influencing large-for-gestation birth weight in singletons born after in vitro fertilization

Korošec

Frangež

Steblovnik

et al. 2015

J Assist Reprod Genet

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Purpose Higher risk for birth of singletons being large for gestational age (LGA) has been revealed after in vitro fertilization (IVF) frozen-thawed embryo-transfer (FET). This phenomenon is now being investigated, since there is a speculation that these neonates could suffer from underlying epigenetic disturbances. The aim of the study was to expose independent LGA risk factors and to identify those connected to the IVF techniques. Methods Altogether, 4508 singleton pregnancies and births were included in the cohort case-matched study. Two hundred eleven singleton pregnancies and births after FET and 916 after fresh embryo transfer (ET) were included into two study groups. The IVF procedures were performed at the University Medical Centre Ljubljana between 2004 and 2011. For each IVF pregnancy, three matched consecutive controls after natural conception were included. Using logistic regression models, we observed LGA connection to maternal parameters (smoking, hypertension, parity, BMI, gestational diabetes, IVF conception, FET, double ET, and ICSI procedure).Results Singletons born after FET had a significantly higher risk for being LGA (p=0.032; OR 1.697; 95 % CI 1.047-2.752). BMI 25-30 was a significant independent risk factor for LGA in the IVF groups (FET p=0.041, OR 2.460, 95 % CI 1.030-5.857 and fresh ET p=0.003; OR 2.188, 95 % CI 1.297-3.691). ICSI and double ET had no significant effect on LGA occurrence. Conclusions Besides maternal BMI, FET is a significant independent LGA risk factor in IVF patients. Other observed factors (smoking, hypertension, multiparity, GDM, ICSI procedure, or number of embryos transferred) do not influence LGA risk significantly.

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“…Analyzing these results, the question arises as to why FET has a higher average delivery rate, compared to fresh ET? Why is it that with the advancing age of patients, this difference increases more?2 Why are there higher miscarriage rates after the ET of thawed blastocysts, compared to thawed early‐cleavage embryos?4 What is the reason that children born after FET have healthier babies and fewer complications than those who have been implanted with fresh embryos?5 …”

Section: Introductionmentioning

confidence: 99%

Theory about the Embryo Cryo‐Treatment

Vladimirov

Tacheva

Dı́ez

2017

Reprod Medicine & Biology

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BackgroundTo create hypothesis, which can give a logical explanation related to the benefits of freezing/thawing embryos. Cryopreservation is not only a technology used for storing embryos, but also a method of embryo treatment that can potentially improve the success rate in infertile couples.MethodsFrom the analysis of multiple results in assisted reproductive technology, which have no satisfactory explanation to date, we found evidence to support a ‘therapeutic’ effect of the freezing/thawing of embryos on the process of recovery of the embryo and its subsequent implantation.ResultsFreezing/thawing is a way to activate the endogenous survival and repair responses in preimplantation embryos. Several molecular mechanisms can explain the higher success rate of ET using thawed embryos compared to fresh ET in women of advanced reproductive age, the higher miscarriage rate in cases of thawed blastocyst ET compared to thawed ET at early cleavage embryo, and the higher perinatal parameters of born children after thawed ET. Embryo thawing induces a stress. Controlled stress is not necessarily detrimental, because it generates a phenomenon that is counteracted by several known biological responses aimed to repair mitochondrial damage of membrane and protein misfolding. The term for favorable biological responses to low exposures to stress is called hormesis.ConclusionsThis thesis will summarize the role of cryopreservation in the activation of a hormetic response, preserving the mitochondrial function, improving survival, and having an impact on the process of implantation, miscarriage, and the development of pregnancy.

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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

Cited by 466 publications

References 27 publications

Increased risk of large-for-gestational age birthweight in singleton siblings conceived with in vitro fertilization in frozen versus fresh cycles

Increased risk of large-for-gestational age birthweight in singleton siblings conceived with in vitro fertilization in frozen versus fresh cycles

Independent factors influencing large-for-gestation birth weight in singletons born after in vitro fertilization

Theory about the Embryo Cryo‐Treatment

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