Infertility. Trends in the incidence of births and multiple births and the factors that determine the probability of multiple birth after IVF treatment

Author: Engmann Lawrence  

Publisher: Oxford University Press

ISSN: 1460-2350

Source: Human Reproduction, Vol.16, Iss.12, 2001-12, pp. : 2598-2605

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Abstract

BACKGROUND: We aimed to review trends in the probability of birth and multiple birth before and after the legal restriction limiting the maximum allowable number of embryos transferred, and to examine factors that determine the probability of multiple birth following IVF treatment. METHODS: We analysed data relating to 7170 IVF and 530 intracytoplasmic sperm injection cycles reaching embryo transfer undertaken by 4417 women at a single tertiary referral assisted conception centre in the UK between 1984 and 1997. Probability of birth, and of proportion of multiple births among those who gave birth, was explored using logistic regression analysis. RESULTS: Between 1984 and 1997 there was a significant increase in probability of birth but no change in the probability of multiple birth. The trend in probability of birth was almost wholly explained by the significant increase in number of embryos created per cycle. Pooling all the data, risk factors for increased chance of birth and multiple birth were: younger age (<35 years),="" diagnoses="" other="" than="" tubal="" infertility,="" fewer="" than="" three="" previous="" unsuccessful="" cycles,="" previous="" ivf="" live="" birth="" and="" a="" large="" number="" of="" embryos="" created.="" given="" these="" factors,="" increasing="" the="" number="" of="" embryos="" transferred="" did="" not="" increase="" the="" chance="" of="" a="" birth,="" but="" did="" increase="" the="" chance="" of="" a="" multiple="" birth.="" conclusions:="" the="" probability="" of="" birth="" has="" increased="" and="" the="" probability="" of="" multiple="" birth="" has="" remained="" unchanged,="" despite="" legislation="" limiting="" the="" number="" of="" embryos="" transferred="" in="" the="" uk.="" efforts="" should="" be="" made="" to="" reduce="" the="" incidence="" of="" multiple="" births="" by="" transferring="" fewer="" embryos,="" especially="" in="" the="" presence="" of="" good="" prognostic="" factors="" for="" birth.="">