Haemoglobin F levels in sudden infant deaths.

Fetal haemoglobin levels have been measured prospectively in 135 autopsy cases of sudden, unexpected infant deaths (31 pre-term, 104 full term) using standard laboratory methods. These results have been compared with Hb F values from a normal control group of 570 living infants (145 pre-term, 425 full-term) with a post-conceptional age < 90 weeks. The gestational age was established for all live controls and sudden infant deaths. The results show that full-term (> 38 weeks gestational age) sudden infant death victims as a group have significantly elevated Hb F levels (chi 2 = 25.20, P < 0.001) when compared to the gestational age matched control group. Pre-term (< 38 weeks gestational age) SIDs show no significant differences from the pre-term control group (chi 2 = 1.20, n.s.) The division of the controls into pre- and full-term groups demonstrates major differences between the post-natal Hb F fall in pre- and full-term infants. Use of post-conceptional age as a growth marker does not produce comparability with full-term infants. Extensive controls were carried out to confirm the reliability of post-mortem Hb F assays, and comparability with in vivo estimation. No significant or systematic differences between pre- and post-mortem samples were identified, nor were any significant differences found on post-mortem storage up to 72 h.