Transformed alpha-fetoprotein (t-AFP) levels in women with threatened preterm labor.

Background/aims: To evaluate maternal serum transformed alpha-fetoprotein (MSt-AFP) levels, a new molecular conformation of AFP was used in cases of threatened preterm labor (TPL).

Methods: Prospective case-control study. Maternal serum levels of classical AFP and transformed AFP (t-AFP) were compared between 2 groups matched by gestational age: 25 women with TPL and 25 healthy pregnant women as controls.

Results: There was no significant difference in classical maternal serum AFP (MSAFP) levels between the 2 groups. In contrast, MSt-AFP levels were significantly lower in cases of TPL than in the control group [7.64 (1.78-29.06) vs. 33.38 (13.80-190.50) ng/ml; p = 0.006]. Similarly, the t-AFP:AFP ratio was also decreased in the TPL group [0.04 (0.004-0.12) vs. 0.16 (0.05-0.80); p = 0.008]. There was no significant correlation between MSAFP and MSt-AFP levels.

Conclusions: MSt-AFP levels are decreased in women with TPL.