A LONGITUDINAL-STUDY OF MATERNAL SERUM VASCULAR ENDOTHELIAL GROWTH-FACTOR IN EARLY-PREGNANCY

Using a competitive radioimmunoassay to measure total immunoreactive v ascular endothelial growth factor (VEGF), we describe for the first ti me longitudinal changes in serum VEGF in early pregnancy. The measurem ents were obtained from 26 women following the transfer of cryopreserv ed embryos; 18 singleton and eight twin pregnancies were identified by ultrasound at 6 weeks gestation and subsequently delivered as live bi rths. Subjects did not have corpora lutea and exogenous hormone suppor t was provided for the first 70 days of pregnancy. Serum VEGF increase d approximately 30 days after embryo transfer and thereafter continued to rise in both singleton and twin pregnancies over a period of 20-40 days after which concentrations remained elevated. The longitudinal p rofile of serum VEGF concentrations was characterized by a logistic cu rve for singleton and twin pregnancies; the profile of VEGF concentrat ions in the twin pregnancies was significantly higher than in the sing leton pregnancies (P < 0.0001), Profiles of the longitudinal concentra tions of serum human chorionic gonadotrophin (HCG), oestradiol and pro gesterone were created by polynomial regression for singleton and twin pregnancies, The VEGF profiles were positively correlated with the pr ofiles of HCG (r = 0.34, P = 0.02) and oestradiol (r = 0.36, P = 0.07) but not progesterone (r = 0.16, P = 0.32). Serum VEGF concentrations in the singleton thawed embryo pregnancies were compared with gestatio n-matched normal singleton pregnancies with corpora lutea, Concentrati ons of VEGF were significantly (P = 0.004) greater in the pregnancies with corpora lutea although this difference became less marked with ad vancing gestation. In addition to its important role in angiogenesis, we speculate that VEGF is involved in mechanisms which control the mat ernal cardiovascular adaptation to pregnancy.