PURPOSE: to verify the fetal heart rate (FHR) patterns of large for gestational age (LGA) fetuses in pregnancies at term complicated by pregestational diabetes. METHODS: fetal surveillance was performed weekly in 64 fetuses of mothers with pregestational diabetes. Inclusion criteria were: diagnosis of pregestational diabetes mellitus, single pregnancy, alive fetus, absence of fetal anomalies, and computerized cardiotocography performed at the 37th week of gestation. Exclusion criteria included: postnatal diagnosis of fetal anomalies and delivery not performed at the local hospital. The FHR patterns were studied with computerized cardiotocography and the parameters were analyzed according to a fetal weight as LGA (birth weight above percentile 90). The cardiotocography parameters included: basal FHR, episodes of high variation, episodes of low variation, and short-term variation. RESULTS: forty-two patients fulfilled the proposed criteria. Ten (23.8%) newborns were LGA. Normal criteria were met in all performed examinations. FHR accelerations (above 15 bpm) were present in 7 (70%) LGA cases and in 29 (90.6%) non-LGA (p=0.135). Accelerations were more frequent in the non-LGA group (1.5±1.3 accelerations/10 min) when compared to LGA group (0.8±0.9 accelerations/10min, p=0.04, Mann-Whitney test). The high variation episodes were detected in all cases. The mean FHR variation in these episodes was different in the LGA group (16.2±2.5 bpm) when compared to the non-LGA group (19.7±4.2 bpm, p=0.02, Mann-Whitney test). CONCLUSION: the FHR patterns of non-LGA (higher frequency of accelerations and higher FHR variation in the high variation episodes) reflect parameters commonly analyzed by traditional cardiotocography of a healthy fetus. This fact appears to confirm the patterns of better oxygen supply to the fetuses less compromised by diabetes in pregnancy.
Cardiotocography; Heart rate; fetal; Fetal macrosomia; Diabetes mellitus
