Objective: The interrelationships between maternal hormone levels and placental dysfunction in mothers bearing children with intrauterine growth retardation remain unclear. We have examined some endocrinological aspects of intrauterine growth retardation and, in particular, tested whether low levels of GH and IGF-I in maternal serum are associated with direct evidence of placental dysfunction.
Design: Prospective, descriptive and comparative.
Patients: Women with singleton pregnancies: 48 with a small for gestation fetus (SGA) (estimated fetal weight less than -1.5 standard deviation scores) and 28 with an appropriate for gestation fetus (AGA).
Measurements: Maternal serum GH, IGF-I, IGFBP-1 and 3 were determined, and fetal weight and umbilical artery pulsatility index (PI) was estimated by ultrasonography and Doppler ultrasound at 33 weeks gestational age.
Results: Serum IGF-I was lower in the SGA group (246 vs 297 micrograms/l, P = 0.03) but GH and IGFBP-1 and -3 did not differ between the groups. In the 16 SGA pregnancies with increased PI, IGF-I concentration was low (218 micrograms/l, quartiles 149-265), whereas in the 32 with normal PI, IGF-I was 269 micrograms/l, quartiles 219-382. Serum IGFBP-1 was increased in the high PI group compared to the normal PI group (161 micrograms/l vs 113, P = 0.05).
Conclusion: Maternal serum IGF-I concentration was lower in small for gestational age pregnancies with increased pulsatility of the umbilical artery blood flow, compared to small for gestational age pregnancies with normal umbilical blood flow, which in turn was close to the IGF-I concentration in appropriate for gestational age pregnancies. Growth hormone concentrations did not differ among the groups.