Table 1 : Descriptive summary of studies utilising non-invasive fetal electrocardiogram for NIEA analysis
Year | Paper | Study population | Inclusion criteria | Definition of IUGR | Acquisition method | Signal acquisition | Signal processing |
|---|---|---|---|---|---|---|---|
1981 | Karinemi et al. | Case control study | N = 65 from normal pregnancies with no fetal acidosis at birth. n = 68 with IUGR. n = 84 with post dates pregnancies | BPD < 5% | NIFECG using HP 8030A Cardiotocograph | Recorded manually on magnetic tape and digitalized at a 1000 samples per second)a | R-R intervals detected no description provided)a. DI sampled over 5 min. Upper rejection limit of 5 bpm was utilised |
1982 | Brambati et al. | Case control study | N = 26 of fetuses suspected to be small for dates | Small for dates by ultrasound or clinical exam (no explanation given) BW < 10% postnatally. | NIFECG- system not specified | N/A | MECG subtraction method utilised. Signal delayed by 180 ms and 50 complexes averaged |
1986 | Pardi et al. | Prospective cohort study | 25 to 41 weeks of gestation. n = 68. Fetuses with malformations excluded | AC < 5% | NIFECG- system not specified | N/A | MECG subtraction method utilised. Signal delayed by 180 ms and 50 complexes averaged |
2012 | Graatsma et al. | Prospective cohort study | 20–42 weeks of gestation. Control (n = 90),IUGR (n = 30) | EFW ≤10% and BW ≤10% corrected for GA | NIFECG. Monica AN24. 5 electrodes utilised | Recorded with a sample frequency of 1000 Hz. Duration = 7 h | In depth analysis available from Pieri et al.b MECG subtraction method utilised. 50 FECG complexes averaged |
2015 | Stampalija et al. | Case control study | 26–34 weeks. IUGR n = 22, Control n = 37. Singleton pregnancies | AC < 5% | NIFECG. Monica healthcare. 5 electrodes utilised transabdominally | 40 min recording. Sample frequency of 900 Hz | MECG subtraction method as filter. FECG complexes averaged over a 2 s window. PRSA applied to entire trace STV measured using Dawes Redman criteria |
2016 | Stampalija et al. | Case control study | 25–40 weeks. IUGR (n = 66). Control (n = 79) Singleton pregnancies | AC < 5% | NIFECG. Monica healthcare. 5 electrodes utilised transabdominally | 37 min. | R-R wave pulse intervals were calculated with an accuracy of 1 ms. MECG subtraction method as filter. FECG complexes averaged over a 2 s window. PRSA applied to entire trace |
2016 | Fuchs et al. | Prospective case control study | 28–42 weeks. IUGR = 93, IUGR with brain sparing = 37 and 324 healthy pregnancies | EFW < 5% and only asymmetrical IUGR considered. BW was < 10% and ponderal index < 10% at birth | NIFECG. KOMPOREL system. 6 electrodes on maternal abdomen, | 30 min recording. No further information provided | No information provided |
2016 | Fuchs et al. | Prospective case control study | 28–40 weeks. IUGR with normal CPR (n = 110), IUGR with decreased CPR (n = 29) and normal pregnancies (n = 549) | EFW < 5% and only asymmetrical IUGR considered. BW was < 10% and ponderal index < 10% at birth | NIFECG. KOMPOREL system. 6 electrodes on maternal abdomen, | 30 min recording. No further information provided | No information provided |
2017 | Velayo et al. | Human- case control study | 20–34 weeks IUGR n = 15, Control n = 20. Singleton pregnancies | EFW and AC < 10% | NIFECG 14 electrodes transabdominally | 20 min recordings Bipolar recording. Sampling every 1 ms at 1 kHz | 1-100 Hz band pass filtering. FECG signal averaging carried out. |