Fetal middle cerebral artery Doppler to time second and subsequent fetal transfusions for red cell alloimmunisation.

母亲和未出生的婴儿血型不匹配会导致抗体的产生，这种抗体会破坏婴儿的红细胞，导致贫血。治疗包括在母亲子宫内向婴儿输血，这在怀孕期间经常需要重复几次。这项随机试验将评估超声波检查是否可以用于第二次或随后的胎儿输血，以及这对婴儿健康的影响。

Blood group incompatability between a mother and her unborn baby can result in the production of antibodies that can damage the baby's red blood cells, causing anaemia. Treatment involves a procedure to transfuse blood to the baby while in the mother's uterus, which often needs to be repeated several times during a pregnancy. This randomised trial will assess if an ultrasound examination can be used to time second or subsequent fetal transfusions, and the impact this has on infant health.