Open AccessPregnancy‐Specific β 1 Glycoprotein, SP 1 in Maternal Serum During Uncomplicated Single Pregnancies
Author(s) -
Tamsen L.,
Inganäs M.,
Johansson S. G. O.,
Kjessler B.,
Schoultz B.
Publication year - 1984
Publication title -
acta obstetricia et gynecologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.401
H-Index - 102
eISSN - 1600-0412
pISSN - 0001-6349
DOI - 10.3109/00016348409155521
Subject(s) - medicine , pregnancy , ovulation , geometric mean , zoology , gynecology , endocrinology , biology , hormone , statistics , genetics , mathematics
Abstract. Pregnancy‐specific β 1 ‐glycoprotein (SP 1 ) levels in uncomplicated single pregnancies were measured by radio‐immunoassay from the time of ovulation until the 8th week of pregnancy in 129 blood samples from 78 women. SP 1 was detectable in all samples examined from 34 days after the last menstrual period (LMP), and thereafter the SP 1 level increased rapidly with time and 38 to 40 days after LMP the geometric mean SP 1 concentration was 90 μg/l. From pregnancy weeks 8 to 41, SP 1 levels were measured by nephelo‐metry in 1 255 blood samples from 1 255 women. A 95% reference range was established using logarithmic transformation. There was a steady increase in the SP 1 concentration until the last month of pregnancy, in which a tendency to level off was seen, the geometric mean levels ranging from 149 to 170 mg/1. The day‐to‐day variation was studied during 5 consecutive days in 10 women. No significant variation was found. The diurnal variation was studied in blood samples taken every 4th hour during a 24‐hour period form 10 women. A significant decrease was found at midnight and at 4 a.m. The elimination rate of SP 1 from serum was studied in 10 women following labor. Elimination was non‐linear and the time taken for SP 1 to decrease to 50% ranged from 24 to 50 hours. No correlation was found between the concentration of SP 1 and parity, maternal age, or the sex of the infant. The SP 1 concentration was significantly lower in heavier women (> 70 kg) than in lighter women (≤ 70 kg). In some weeks of late pregnancy the SP 1 level showed a correlation to placen‐tal weight and birth weight of the infant.