§ These data are based on statistics collected within the Scottish Health Service on 98.6 per cent. of registered births in 1987. The information on infant deaths has been linked to the clinical information on births, by permission of the Registrar General for Scotland.
§ There are two measures of gestation available in our data. One is an estimate of gestation based on
|APPENDIX 1 TO ANNEX H|
|LIVE BIRTHS WITH EXTIMATED GESTATION LESS THAN 28 WEEKS: SCOTLAND 1987|
|ESTIMATED GESTATION||GESTATION ESTIMATED=CALCULATED||GESTATION ESTIMATED=CALCULATED +/= 1 WEEK||DISCREPANCIES GREATER THAN 1 WEEK BETWEEN MEASURES OF GESTATION||NO. ALL INFANTS|
|No.||No. Surviving to 1 year||Max Age at Death of Others*||No.||No. Surviving to 1 year||Max Age at Death of Others*||No.||No. Surviving to 1 year||Max Age at Death of Others*||No.||No. Surviving to 1 year||%||Max Age at Death of Others*|
§ information alvailable to the clinician, including menstrual history, clinical examination and ultrasound (estimated gestation). The second is the gestation calculated from the date of first day of the last menstrual period (calculated gestation). In clinical practice it is likely that the clinician's best estimate of gestation will be the one acted upon where there is a discrepancy between it and the calculated gestation. The gestation quoted in both definitions is in completed weeks.
§ In 1987 there were 187 live births with an estimated gestation of less than 28 weeks. In 85 (45 per cent.) the estimated gestation and the calculated gestation were the same. In 44 (24 per cent.) there was one week's difference between the estimated and calculated gestation. In 56 (31 per cent.) there was a discrepancy of more than one week between the two gestations, or the date of the last menstrual period (and therefore the calculated gestation) was unknown. The appended table shows these three groups separately and totalled.
§ The numbers of live births at each week's estimated gestation is given first. The number of infants who were still alive at the end of the first year of life is in the third column, and in the middle column is the age at death of the oldest infant to die within the first year of life. The ages at death are in completed units of time (H =hours, D =days, W =weeks and M =months).
§ There were no infants born alive below 22 weeks' gestation, and the longest time an infant born at 22 or 23 weeks' gestation survived was three days. The proportions of survivors to the end of the first year increased progessively from 22 per cent. at 24 weeks to 64 per cent. at 27 weeks.