Cohort profile: a national, population-based cohort of children born after assisted conception in the UK (1992–2009): methodology and birthweight analysis

Abstract

PurposeTo generate a large cohort of children born after assisted reproductive technology (ART) in the UK between 1992 and 2009, their naturally conceived siblings (NCS) and matched naturally conceived population (NCP) controls and linking this with health outcome data to allow exploration of the effects of ART. The effects of fresh and frozen embryo transfer on birth weight (BW) were analysed to test the validity of the cohort.ParticipantsChildren recorded on the Human Fertilisation and Embryology Authority (HFEA) register as being born after ART between 1992 and 2009, their NCS and matched NCP controls linked to Office for National Statistics birth registration dataset (HFEA-ONS cohort). This cohort was further linked to the UK Hospital Episode Statistics database to allow monitoring of the child’s post-natal health outcomes up to 2015 (HFEA-ONS-HES subcohort).Findings to dateThe HFEA-ONS cohort consisted of 75 348 children born after non-donor ART carried out in the UK between 1 April 1992 and 31 July 2009 and successfully linked to birth registration records, 14 763 NCS and 164 823 matched NCP controls. The HFEA-ONS-HES subcohort included 63 877 ART, 11 343 NCS and 127 544 matched NCP controls further linked to health outcome data. The exemplar analysis showed that children born after fresh embryo transfers were lighter (BW difference: −131 g, 95% CI: −140 to –123) and those born after frozen embryo transfers were heavier (BW difference: 35 g, 95% CI: 19 to 52) than the NCP controls. The within-sibling analyses were directionally consistent with the population control analyses, but attenuated markedly for the fresh versus natural conception (BW difference: −54 g; 95% CI: −72 to –36) and increased markedly for the frozen versus natural conception (BW difference: 152 g; 95% CI: 113 to 190) analyses.Future plansTo use this cohort to explore the relationship between ART conception and short-term and long-term health outcomes in offspring.

It is not worth postponing frozen embryo transfers after oocyte pickup: A retrospective cohort study based on propensity score matching

“…Apart from the clinical outcomes, another concern is the health of babies conceived by FET. A growing number of studies have shown that FET is associated with an increased risk of high birth weight and macrosomia ( 33 – 36 ). Does the length of interval between OPU and FET affects neonatal outcomes?…”

General health in a cohort of children conceived after assisted reproductive technology in the United Kingdom: a population-based record-linkage study

“…This study used a previously established cohort of children born to women who underwent ART in the United Kingdom between April 1, 1997 and July 31, 2009, their NCS, with 2 NCP controls per ART child matched for age, sex, and multiplicity (Supplemental Table 1). 17 A subgroup of ART children with NCS (sART) was also identified. Record linkage was used to link the Human Fertilisation and Embryology Authority (HFEA) register, the Office for National Statistics (ONS) birth registration dataset, and the Hospital Episode Statistics (HES) database (Supplemental Figures 1 and 2), with details of the linkage methodology previously reported.…”

“…Record linkage was used to link the Human Fertilisation and Embryology Authority (HFEA) register, the Office for National Statistics (ONS) birth registration dataset, and the Hospital Episode Statistics (HES) database (Supplemental Figures 1 and 2), with details of the linkage methodology previously reported. 17 All children conceived after ART in the United Kingdom but born outside of England, Wales, and Scotland; those born after ART to women who permanently lived outside the United Kingdom but traveled there for ART treatment; and those born in Northern Ireland were excluded because it would not be possible to link them to ONS birth records. In addition, siblings born outside of the study period (because their conception status could not be verified) and those born outside of England, Wales, and Scotland were also excluded.…”

“…The original cohort consisted of 63,877 ART children (of which 12,329 ART children had NCS [the sARTsubgroup]), 127,544 matched NCP controls, and 11,343 NCS. 17 The demographic characteristics of the study cohort have been summarized in Supplemental Table 1. 17 In total, 124,252 children contributed 1.6 million person-years of follow-up, with the mean follow-up period being 12.9 years (range, 0e19 years).…”

“…16 The objective of the current study was to assess the association of ART conception with future health by using a previously established cohort of children consisting of those born after ART in the United Kingdom between 1997 and 2009, their NCS, and matched NC population (NCP) controls linked to their hospital records up to March 31, 2016 to provide robust risk estimates and rates of hospital admissions in children born after ART, and to compare these findings to appropriately matched NCP controls and NCS. 17 In addition, comparisons of hospital admissions by type of ART treatment (in vitro fertilization [IVF] vs ICSI, embryo cryopreservation) were also performed.…”