As contribution to a recent debate (James, 1998; Murphy et al., 1997, 1998) the proportion of twins following ovulation induction (OI) or assisted conception (AC) in 1994 in Oxfordshire and West Berkshire was estimate...
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As contribution to a recent debate (James, 1998; Murphy et al., 1997, 1998) the proportion of twins following ovulation induction (OI) or assisted conception (AC) in 1994 in Oxfordshire and West Berkshire was estimated, and by extrapolation the natural twinning rate in England and Wales was judged to have maintained a plateau phase since the 1970s. Similar figures for 1995 and 1996 from the same study, and hence a more stable local estimate, are now provided. The proportions, as before, were estimated from women's responses to a questionnaire within a case[hyphen]control study, with ascertainment from general practitioners' records or hospital case[hyphen]notes for non[hyphen]responders or for those excluded from the study originally. In 1994, 1995 and 1996 the proportion of twins following OI/AC was overall 27% (24%, 30% and 27% respectively). Restriction to the 87% locally resident made no difference. The national crude twinning rate for those years was overall 13·3 per 1000 maternities (12·8, 13·6 and 13·4 respectively).
This article clarifies the use of statistics to describe the success of infertility treatments, with specific emphasis on assisted reproductive technology. A discussion of the January 2000 Society for Assisted Reprodu...
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This article clarifies the use of statistics to describe the success of infertility treatments, with specific emphasis on assisted reproductive technology. A discussion of the January 2000 Society for Assisted Reproductive Technology/Centers for Disease Control report for procedures performed in 1997 is included. Limitations on the use of statistical analysis and the problem of multiple gestation are addressed. A glossary of terms is included for reference.
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