Gestational diabetes alters the fetal heart rate variability during an oral glucose tolerance test: a fetal magnetocardiography study.

OBJECTIVE: Gestational diabetes mellitus (GDM) potentially harms the child before birth. We previously found GDM to be associated with developmental changes in the central nervous system. We now hypothesise that GDM may also impact on the fetal autonomic nervous system under metabolic stress like an oral glucose tolerance test (OGTT). DESIGN: We measured heart rate variability (HRV) of mothers and fetuses during a three-point OGTT using fetal magnetocardiography (fMCG). SETTING: Measurements were performed in the fMEG Centre in Tübingen. POPULATION: After exclusion of 23 participants, 13 pregnant women with GDM and 36 pregnant women with normal glucose tolerance were examined. METHODS: All women underwent the same examination setting with OGTT during which fMCG was recorded three times. MAIN OUTCOME MEASURE(S): Parameters of heart rate variability were measured. RESULTS: Compared with mothers with normal glucose regulation, mothers with GDM showed increased heart rate but no significant differences of maternal HRV. In contrast, HRV in fetuses of mothers with GDM differed from those in the metabolically healthy group regarding standard deviation normal to normal beat (SDNN) (P = 0.012), low-frequency band (P = 0.008) and high-frequency band (P = 0.031). These HRV parameters exhibit a decrease only in GDM fetuses during the second hour of the OGTT. CONCLUSIONS: These results show an altered response of the fetal autonomic nervous system to metabolic stress in GDM-complicated pregnancies. Hence, disturbances in maternal glucose metabolism might not only impact on the central nervous system of the fetus but may also affect the fetal autonomic nervous system. TWEETABLE ABSTRACT: Metabolic stress reveals a different response of fetal autonomic nervous system in GDM-complicated pregnancies.

Functional brain development in growth-restricted and constitutionally small fetuses: a fetal magnetoencephalography case-control study.

OBJECTIVE: Fetal magnetoencephalography records fetal brain activity non-invasively. Delayed brain responses were reported for fetuses weighing below the tenth percentile. To investigate whether this delay indicates delayed brain maturation resulting from placental insufficiency, this study distinguished two groups of fetuses below the tenth percentile: growth-restricted fetuses with abnormal umbilical artery Doppler velocity (IUGR) and constitutionally small-for-gestational-age fetuses with normal umbilical artery Doppler findings (SGA) were compared with fetuses of adequate weight for gestational age (AGA), matched for age and behavioural state. DESIGN: A case-control study of matched pairs. SETTING: Fetal magnetoencephalography-Center at the University Hospital of Tuebingen. POPULATION: Fourteen IUGR fetuses and 23 SGA fetuses were matched for gestational age and fetal behavioural state with 37 healthy, normal-sized fetuses. METHODS: A 156-channel fetal magentoencephalography system was used to record fetal brain activity. Light flashes as visual stimulation were applied to the fetus. The Student's t-test for paired groups was performed. MAIN OUTCOME MEASURE: Latency of fetal visual evoked magnetic responses (VER). RESULTS: The IUGR fetuses showed delayed VERs compared with controls (IUGR, 233.1 ms; controls, 184.6 ms; P = 0.032). SGA fetuses had similar evoked response latencies compared with controls (SGA, 216.1 ms; controls, 219.9 ms; P = 0.828). Behavioural states were similarly distributed. CONCLUSION: Visual evoked responses are delayed in IUGR fetuses, but not in SGA. Fetal behavioural state as an influencing factor of brain response latency was accounted for in the comparison. This reinforces that delayed brain maturation is the result of placental insufficiency.

Fetal magnetocardiography (fMCG) to monitor cardiac time intervals in fetuses at risk for isoimmune AV block.

OBJECTIVE: The objective of this report is to detect cardiac time intervals (CTIs) in fetuses exposed to SSA/Ro-SSB/La antibodies in relation to gestational age (GA) and fetal weight and compared them with a control cohort. METHODS: Fetal magnetocardiography (fMCG) recordings were conducted on a biomagnetic device dedicated to obstetrical measurement starting in the second trimester. Fetal cardiac time intervals of 87 healthy fetuses of normal gestation (control group) were compared to 11 fetuses exposed to maternal SSA/Ro-SSB/La antibodies (study group). RESULTS: fCTIs were analyzed starting at 17 weeks of GA. Atrial and ventricular depolarization times increased with GA in both groups. PQ segments were significantly longer in the study group (50.8 ms vs. 60.2 ms; p < 0.001) independent of GA or fetal weight. PQ segment prolongation was more obvious in the study group prior to 30 weeks of GA. CONCLUSION: PQ segment prolongation can be interpreted as early AV-node involvement caused by maternal SSA/Ro-SSB/La antibodies. The age dependency of the PQ segment should be taken into account in further studies.