Factors influencing mortality and morbidity after clinically apparent intraventricular haemorrhage

In other conditions associated with placental oedema-such as the fetofetal transfusion syndrome, and hydrops fetalis due to rhesus isoimmunisation or congenital syphilis-low levels of the maternally synthesised immunoglobulin IgG have been found in the cord bloods of the infants.7 8 These findings suggest that placental transfer ofIgG is also reduced. We, like Chiang and Wei,7 found that the cord IgG levels were below the normal range for a white population (72-175 IU/ml). As studies have shown that mothers in tropical countries, and therefore their babies, tend to have higher levels of IgG, it is likely that the levels are even further outside the normal range for a Thai population. Unfortunately no data are available, but studies on unaffected infants and their mothers from Taiwan7 support this suggestion. The whole complex pathophysiology of oedema in the fetus and newborn infant needs further study. Alpha-thalassaemic hydrops fetalis is an example of the most extreme form of intrauterine oedema and provides a unique model for investigation of the underlying mechanisms of oedema formation. Now that rhesus isoimmunisation can be prevented (or its effects altered in utero), there is no other condition in which hydrops fetalis can be predicted and thus be accessible to study from early pregnancy.