Maternal serum alpha-fetoprotein, fetal middle cerebral artery blood flow velocity and fetal haemoglobin in pregnancies at risk of fetal anaemia.

OBJECTIVES

To evaluate the relationships between maternal serum alpha-fetoprotein (MSAFP) levels and both middle cerebral artery (MCA) peak systolic velocity and fetal haemoglobin in women at risk of fetal anaemia.

METHODS

Forty-one measurements of MSAFP were carried out in 22 women at risk of fetal anaemia (16 alloimmunised patients and 6 cases of parvovirus infection) who were monitored by using MCA Doppler measurements. The relationships between MSAFP (MoM) and both MCA peak systolic velocity (z-scores) and fetal haemoglobin (MoM) were studied.

RESULTS

There were significant correlations between MSAFP and both MCA Doppler measurements (r = 0.56, p = 0.00017) and fetal haemoglobin (n = 13, r = -0.71, p = 0.006). MSAFP was higher in cases with fetal anaemia (n = 10) than in those with normal haemoglobin levels (n = 3) (1.7 +/- 0.4 vs 0.8 +/- 0.1 MoM; p = 0.006). In cases of alloimmunised pregnancies with fetal anaemia, MSAFP elevations preceded the presence of increased MCA Doppler velocity by 2.7 weeks (range 0-9 weeks).

CONCLUSION

MSAFP is significantly correlated with both MCA Doppler measurements and fetal haemoglobin. Elevations of MSAFP may appear earlier than MCA Doppler abnormalities in cases of fetal anaemia associated with red blood cell alloimmunisation.