Values of Alpha-fetoprotein of Maternal Serum in Normal Pregnancy

Kim, Mok Jin; Han, Kuk Sun; An, Jae Hong; Suh, Jeung Ho; Lee, Young Gi; Park, Yoon Kee; Lee, Tae Hyung

Abstract

Alphafetoprotein(AFP) is a glycoprotein synthesized by the fetus early in gestation by the yolk sac and later by the gastrointestinal tract and liver. The concentration of AFP is highest in fetal serum and amniotic fluid around 13th week, and 32nd week in maternal serum. Some conditions are associated with abnormal maternal serum AFP concentration. For examples, neural tube defects, omphalocele, renal anomalies are associated with elevated maternal serum AFP and fetal death, chromosomal trisomies are associated with low level of maternal serum AFP. So maternal serum AFP screening plays a significant role in assessing candidates for prenatal diagnosis and prenatal counselling in pregnant women. This study evaluates the normal ranges of AFP using enzyme immunoassay in normal pregnant women. We studied 500 normal pregnant women who visited the Department of Obstetrics & Gynecology, Yeungnam Medical Center, Yeungnam University during the period through January, 1993 to September, 1996. The group of the study were selected randomly at various gestational ages from 8 to 41 weeks. The results were summarized as follows: 1. The lowest level of AFP in our study group was 2.1ng/ml at 8 weeks of gestation. Thereafter serum alpha-fetoprotein concentrations rose rapidly to reach a peak value at 32nd week. 2. The mean levels of AFP in the primipara and multipara were 166.37+/-12.06ng/ml, and 223.78+/-14.00ng/ml, respectively, showing stastiscally significant difference between these two groups(p<0.01). 3. The mean levels of AFP between mothers who delivered male and female babies were 192.96+/-13.00ng/ml, and 194.29+/-13.84ng/ml, respectively, without statistically significant difference(p>0.05). 4. The normal ranges of maternal serum AFP according to each gestational week were evaulated.