Outcome of pregnancies associated with raised serum and normal amniotic fluid alpha fetoprotein concentrations.

Outcome of pregnancies associated with raised serum and normal amniotic fluid a fetoprotein concentrations Open neural tube defects are associated with raised concentrations of a fetoprotein in amniotic fluid and maternal serum. Raised maternal serum a fetoprotein concentrations have also been associated with fetal distress, intrauterine death, threatened abortion, multiple pregnancy, exomphalos, congenital nephrosis, Turner's syndrome, and low birthweight (preterm) infants. On analysing perinatal and maternal morbidity in south Gwent we noted that pregnancies in which a fetoprotein concentrations were high in serum but normal in amniotic fluid seemed to have an increased incidence of complications. We carried out a prospective study to investigate this phenomenon further. women were booked for delivery and 2913 were screened for neural tube defects at 16-18 weeks' gestation by estimation of serum a fetoprotein concentrations (Amersham radio-immunoassay technique). If the concentration was abnormal the estimation was repeated within one week when possible, and gestation was assessed ultrasonically. Amniocentesis was performed in those patients in whom the serum a fetoprotein concentration was high on two occasions (>95th centile for gestational age). Those patients with normal amniotic fluid concentrations were reassured and continued their pregnancies. The outcome of pregnancy in these women with normal amniotic fluid concentrations (n= 55) was compared with that in a group of controls comprising 165 consecutive women delivering in the delivery unit during the period of the study. The control group had normal serum a fetoprotein concentrations and did not undergo amniocentesis. The groups were compared for the incidences of severe pre-eclampsia, antepartum haemorrhage , preterm labour, induction, birth weight if less than 2500 g or less than the 10th centile for gestation, Apgar score, gestational age at delivery, fetal abnormalities, and neonatal mortality. They were also compared for maternal age, weight, height, parity, and social class assessed according to the husband's occupation. Comparison was with the x2 test or Fisher's exact test (two tailed) when indicated. Distributions and ranges of age, weight, parity, and social class were similar in both groups. No neural tube defects arose in either group, and fetal abnormalities that did occur were various and relatively minor, such as hypospadias. The incidences of preterm labour, low birth weight, fetal abnormalities, and perinatal mortality were significantly higher in the study group (table). Incidences of antepartum haemorrhage, assisted delivery, severe pre-eclampsia, low Apgar scores, and light for dates infants were also higher but did not reach significance. Three perinatal …