Objective: To determine if maternal alpha fetoprotein (AFP) is elevated in lupus pregnancy and, if so, whether it is associated with treatment or outcome.
Methods: Maternal serum AFP values were obtained once during Weeks 16.3 to 31.7 in 54 pregnancies followed prospectively. AFP was measured by the Maryland State Health Department, who reported the AFP level and a corrected value, multiple of the median (AFP MOM), adjusted for weight, gestational age, and insulin dependent diabetes. Controls were 1001 consecutive samples measured by the same laboratory.
Results: AFP MOM was higher in lupus pregnancies (1.425 +/- 0.73 vs 1.169 +/- 0.50, p = 0.001), as were the unadjusted AFP levels (lupus 68.26 +/- 42.2, control 52.49 +/- 27.25, p = 0.001). Of lupus pregnancies 7.4 vs 2.6% of control pregnancies had an abnormal AFP MOM (p = 0.06). The 4 patients with abnormal AFP-MOM, using the 2.3 cutoff, were taking more prednisone (27.25 +/- 18.54 mg vs 10.85 +/- 12.29 mg, p = 0.02), were more likely to have delivered preterm (31.50 +/- 36.31 weeks, p = 0.02), and were more likely to have a high anticardiolipin (aCL) antibody during the pregnancy (p = 0.03).
Conclusion: AFP is higher in lupus than in control pregnancies, without any increase in neural tube or other birth defects. An abnormal maternal serum AFP level is associated with higher prednisone dose, preterm delivery and aCL. Patients and obstetricians need to be aware that an elevated maternal AFP in lupus pregnancy is not necessarily due to a birth defect, and may be predictive of preterm delivery.