Obstetric and perinatal outcomes after either fresh or thawed frozen embryo transfer

an analysis of 112,432 singleton pregnancies recorded in the Human Fertilisation and Embryology Authority anonymized dataset

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

OBJECTIVE: To explore obstetric and perinatal outcomes in singleton pregnancies occurring as a result of fresh and thawed frozen embryo transfer using anonymized Human Fertilisation and Embryology Authority data.

DESIGN: Retrospective cohort study.

SETTING: Not applicable.

PATIENT(S): Singleton births after IVF/intracytoplasmic sperm injection cycles in the United Kingdom (1991-2011).

INTERVENTION(S): A total of 112,432 cycles (95,911 fresh and 16,521 frozen) were analyzed using multivariate logistic regression to explore associations between type of embryo transferred (frozen vs. fresh) and obstetric and perinatal outcomes. Relative risks (RRs) and their 99.5% confidence intervals (CIs) were calculated using Stata 14 MP, adjusting for potential confounders.

MAIN OUTCOME MEASURE(S): Birth weight.

RESULT(S): The adjusted RR (99.5% CI) of low birth weight [0.73 (0.66-0.80)] and very low birth weight [0.78 (0.63-0.96)] were all lower after frozen embryo transfer; however, RR of having a high birth weight baby was higher [1.64 (1.53-1.76)]. There was no difference in RR of preterm birth [0.96 (0.88-1.03)], very preterm birth [0.86 (0.70-1.05)], and congenital anomalies [0.86 (0.73-1.01)].

CONCLUSION(S): The findings of low birth and very low birth weight after thawed frozen embryo transfer are consistent with the literature and provide reassurance regarding the outcome of pregnancies after frozen embryo transfers. However, they highlight the possibility of high birth weight in these babies. Because these results are based on observational data, further evidence from randomized, controlled trials is needed before elective cryopreservation of all embryos is practiced in preference to the current practice of transfer of fresh embryos.

Original languageEnglish
Pages (from-to)1703-1708
Number of pages6
JournalFertility and Sterility
Volume106
Issue number7
Early online date24 Sep 2016
DOIs
Publication statusPublished - 7 Dec 2016

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Embryology
Embryo Transfer
Fertilization
Obstetrics
Pregnancy
Birth Weight
Very Low Birth Weight Infant
Premature Birth
Embryonic Structures
Parturition
Confidence Intervals
Intracytoplasmic Sperm Injections
Cryopreservation
Low Birth Weight Infant
Pregnancy Outcome
Cohort Studies
Randomized Controlled Trials
Retrospective Studies
Logistic Models
Datasets

Keywords

  • frozen replacement cycles
  • ICSI
  • IVF
  • obstetric outcomes
  • perinatal outcomes

Cite this

@article{9cea7a9c5710488088e4ef981cb6c32f,
title = "Obstetric and perinatal outcomes after either fresh or thawed frozen embryo transfer: an analysis of 112,432 singleton pregnancies recorded in the Human Fertilisation and Embryology Authority anonymized dataset",
abstract = "OBJECTIVE: To explore obstetric and perinatal outcomes in singleton pregnancies occurring as a result of fresh and thawed frozen embryo transfer using anonymized Human Fertilisation and Embryology Authority data.DESIGN: Retrospective cohort study.SETTING: Not applicable.PATIENT(S): Singleton births after IVF/intracytoplasmic sperm injection cycles in the United Kingdom (1991-2011).INTERVENTION(S): A total of 112,432 cycles (95,911 fresh and 16,521 frozen) were analyzed using multivariate logistic regression to explore associations between type of embryo transferred (frozen vs. fresh) and obstetric and perinatal outcomes. Relative risks (RRs) and their 99.5{\%} confidence intervals (CIs) were calculated using Stata 14 MP, adjusting for potential confounders.MAIN OUTCOME MEASURE(S): Birth weight.RESULT(S): The adjusted RR (99.5{\%} CI) of low birth weight [0.73 (0.66-0.80)] and very low birth weight [0.78 (0.63-0.96)] were all lower after frozen embryo transfer; however, RR of having a high birth weight baby was higher [1.64 (1.53-1.76)]. There was no difference in RR of preterm birth [0.96 (0.88-1.03)], very preterm birth [0.86 (0.70-1.05)], and congenital anomalies [0.86 (0.73-1.01)].CONCLUSION(S): The findings of low birth and very low birth weight after thawed frozen embryo transfer are consistent with the literature and provide reassurance regarding the outcome of pregnancies after frozen embryo transfers. However, they highlight the possibility of high birth weight in these babies. Because these results are based on observational data, further evidence from randomized, controlled trials is needed before elective cryopreservation of all embryos is practiced in preference to the current practice of transfer of fresh embryos.",
keywords = "frozen replacement cycles, ICSI, IVF, obstetric outcomes, perinatal outcomes",
author = "Abha Maheshwari and Raja, {Edwin Amalraj} and Siladitya Bhattacharya",
note = "A.M. reports funding from the National Institute for Health Research (NIHR); speaker fees for educational meetings; travel and accommodation reimbursement as an invited speaker at national and international conferences; and royalties from a textbook on infertility. E.A.R. reports funding from government agencies; and travel and meeting expenses supported by the institution. S.B. reports funding from government agencies (NIHR, Scottish Chief Scientist Office); royalties from a textbook on infertility; travel and accommodation as invited speaker at national and international conferences; and financial support to department/institution for seminars and to colleagues for travel, accommodation and attendance at conferences.",
year = "2016",
month = "12",
day = "7",
doi = "10.1016/j.fertnstert.2016.08.047",
language = "English",
volume = "106",
pages = "1703--1708",
journal = "Fertility and Sterility",
issn = "0015-0282",
publisher = "ACADEMIC PRESS INC ELSEVIER SCIENCE",
number = "7",

}

TY - JOUR

T1 - Obstetric and perinatal outcomes after either fresh or thawed frozen embryo transfer

T2 - an analysis of 112,432 singleton pregnancies recorded in the Human Fertilisation and Embryology Authority anonymized dataset

AU - Maheshwari, Abha

AU - Raja, Edwin Amalraj

AU - Bhattacharya, Siladitya

N1 - A.M. reports funding from the National Institute for Health Research (NIHR); speaker fees for educational meetings; travel and accommodation reimbursement as an invited speaker at national and international conferences; and royalties from a textbook on infertility. E.A.R. reports funding from government agencies; and travel and meeting expenses supported by the institution. S.B. reports funding from government agencies (NIHR, Scottish Chief Scientist Office); royalties from a textbook on infertility; travel and accommodation as invited speaker at national and international conferences; and financial support to department/institution for seminars and to colleagues for travel, accommodation and attendance at conferences.

PY - 2016/12/7

Y1 - 2016/12/7

N2 - OBJECTIVE: To explore obstetric and perinatal outcomes in singleton pregnancies occurring as a result of fresh and thawed frozen embryo transfer using anonymized Human Fertilisation and Embryology Authority data.DESIGN: Retrospective cohort study.SETTING: Not applicable.PATIENT(S): Singleton births after IVF/intracytoplasmic sperm injection cycles in the United Kingdom (1991-2011).INTERVENTION(S): A total of 112,432 cycles (95,911 fresh and 16,521 frozen) were analyzed using multivariate logistic regression to explore associations between type of embryo transferred (frozen vs. fresh) and obstetric and perinatal outcomes. Relative risks (RRs) and their 99.5% confidence intervals (CIs) were calculated using Stata 14 MP, adjusting for potential confounders.MAIN OUTCOME MEASURE(S): Birth weight.RESULT(S): The adjusted RR (99.5% CI) of low birth weight [0.73 (0.66-0.80)] and very low birth weight [0.78 (0.63-0.96)] were all lower after frozen embryo transfer; however, RR of having a high birth weight baby was higher [1.64 (1.53-1.76)]. There was no difference in RR of preterm birth [0.96 (0.88-1.03)], very preterm birth [0.86 (0.70-1.05)], and congenital anomalies [0.86 (0.73-1.01)].CONCLUSION(S): The findings of low birth and very low birth weight after thawed frozen embryo transfer are consistent with the literature and provide reassurance regarding the outcome of pregnancies after frozen embryo transfers. However, they highlight the possibility of high birth weight in these babies. Because these results are based on observational data, further evidence from randomized, controlled trials is needed before elective cryopreservation of all embryos is practiced in preference to the current practice of transfer of fresh embryos.

AB - OBJECTIVE: To explore obstetric and perinatal outcomes in singleton pregnancies occurring as a result of fresh and thawed frozen embryo transfer using anonymized Human Fertilisation and Embryology Authority data.DESIGN: Retrospective cohort study.SETTING: Not applicable.PATIENT(S): Singleton births after IVF/intracytoplasmic sperm injection cycles in the United Kingdom (1991-2011).INTERVENTION(S): A total of 112,432 cycles (95,911 fresh and 16,521 frozen) were analyzed using multivariate logistic regression to explore associations between type of embryo transferred (frozen vs. fresh) and obstetric and perinatal outcomes. Relative risks (RRs) and their 99.5% confidence intervals (CIs) were calculated using Stata 14 MP, adjusting for potential confounders.MAIN OUTCOME MEASURE(S): Birth weight.RESULT(S): The adjusted RR (99.5% CI) of low birth weight [0.73 (0.66-0.80)] and very low birth weight [0.78 (0.63-0.96)] were all lower after frozen embryo transfer; however, RR of having a high birth weight baby was higher [1.64 (1.53-1.76)]. There was no difference in RR of preterm birth [0.96 (0.88-1.03)], very preterm birth [0.86 (0.70-1.05)], and congenital anomalies [0.86 (0.73-1.01)].CONCLUSION(S): The findings of low birth and very low birth weight after thawed frozen embryo transfer are consistent with the literature and provide reassurance regarding the outcome of pregnancies after frozen embryo transfers. However, they highlight the possibility of high birth weight in these babies. Because these results are based on observational data, further evidence from randomized, controlled trials is needed before elective cryopreservation of all embryos is practiced in preference to the current practice of transfer of fresh embryos.

KW - frozen replacement cycles

KW - ICSI

KW - IVF

KW - obstetric outcomes

KW - perinatal outcomes

U2 - 10.1016/j.fertnstert.2016.08.047

DO - 10.1016/j.fertnstert.2016.08.047

M3 - Article

VL - 106

SP - 1703

EP - 1708

JO - Fertility and Sterility

JF - Fertility and Sterility

SN - 0015-0282

IS - 7

ER -