Fresh embryo transfer versus frozen embryo transfer in in vitro fertilization cycles: a systematic review and meta-analysis

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.

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

“…In the final follicular phase, the subtle increases in progesterone levels are associated with advancements in the endometrium's ultrastructural morphology and echogenicity, and these levels seem to have a negative impact on embryo implantation [13,14]. These alterations may result in embryo-endometrium asynchrony, and they may decrease the implantation rates during ART treatments [6]. The live birth rates of patients undergoing IVF treatments may decrease when there is an increase in P levels on the day of final oocyte maturation [15].…”

Section: Discussionmentioning

confidence: 99%

Ratio of progesterone-to-number of follicles as a prognostic tool for in vitro fertilization cycles

Roque

Valle

Sampaio

et al. 2015

Self Cite

Purpose To establish a ratio of the P level to the number of follicles (P/F ratio) on the day of human chorionic gonadotropin (hCG) administration and to evaluate whether this ratio is associated with in vitro fertilization (IVF) outcome. Methods This study was conducted between January 2012 and June 2013. A total of 337 patients with cleavage-stage day-3 fresh embryo transfer with P levels ≤1.5 ng/mL on the day of hCG administration were included in the study. The main outcome was ongoing pregnancy rate. Result(s) The P/F ratio was calculated according to the equation (P[ng/mL]/number of follicles) on the day of final oocyte maturation. Using ROC, we established a cut-off level of 0.075 for the P/F ratio. The area under the curve (AUC) (0.756; 95 % confidence interval [CI]: 0.704-0.807) indicated that it was a good prognostic test. In group 1 (patients under 36 years old), the ongoing pregnancy rates were 57 and 30 % for patients with P/F ratios≤.075 and>.075, respectively, (p= 0.003). In group 2 (patients between 36 and 39 years old), the ongoing pregnancy rates were 58 % and 17 % (p=0.001) for patients with P/F ratios ≤.075 and>.075, respectively. In group 3 (patients≥40 years old), the ongoing pregnancy rates were 41.7 and 10.9 % (p=0.001) for patients with P/F ratios≤.075 and>.075, respectively. Conclusions The P/F ratio is a good prognostic test for predicting IVF outcome that can correlate the P level with ovarian response.

“…Therefore, previous studies comparing fresh embryo transfer (ET) with FET are limited due to the morphological differences in their study cohorts. Despite this fact, some studies have reported even higher pregnancy rates following a FET compared to fresh transfers [3,6,7]. In addition, with the advances and optimization made in cryopreservation methods [8], the quality of the frozen embryos and their reproductive potential are at least similar to those observed with fresh embryos [9].…”

Section: Introductionmentioning

confidence: 99%

Reproductive outcome is optimized by genomic embryo screening, vitrification, and subsequent transfer into a prepared synchronous endometrium

Rodriguez-Purata

Lee

Whitehouse

et al. 2016

Purpose The aim of this study is to compare implantation and live birth rates (LBR) between fresh euploid embryo transfers versus cryo-all cycles with a subsequent embryo transfer into a prepared endometrium. Material and Methods This is a retrospective cohort study. Patients who underwent an IVF cycle with PGS with trophectoderm biopsy from January 2011 to July 2015 were included. Patients were divided into three groups: "Fresh Only," "Frozen Embryo Transfer ('FET) Only," and "Fresh ET then FET." For "Fresh Only" group (n = 345), PGS results were received within 24 h. For "FET Only" group (n = 514), results were expected after 24 h, and embryos were cryopreserved after biopsy; only FET was performed in this group (no fresh transfer). For "FET with a previous fresh ET" (n = 139) group, patients underwent a fresh ET with a subsequent FET, in which the same cohort of embryos was utilized. The main outcome measures were pregnancy rate (PR), clinical PR, implantation rate (IR), LBR, and early pregnancy loss rate. Results IRs were statistically higher in the "FET Only" group when compared to the "Fresh Only" group (59.5 vs. 50.6 %, p < 0.01) and the "FET with a previous fresh ET" (59.5 vs. 50.6 %, p < 0.05). LBR was statistically significant in the "FET Only" group when compared to the "Fresh Only" group (57.6 vs. 46.5 %, p < 0.005) but not when compared to "FET with a previous fresh ET" group (57.6 vs. 47.7 %, p = 0.07). Conclusions This analysis suggests euploid embryos to be more likely to implant and achieve a LBR in a synthetic FET cycle than in a fresh cycle.