Analysis of fetal breathing movements at 30-38 weeks of gestation

A Proposed Phonography-Based Measurement of Fetal Breathing Movement Using Segmented Structures with Frequency Splitting

This paper proposes a detection method of fetal breathing movement (FBM) as an important data of fetal well-being. To analyze the chaotic nature of the individual episodes, the frequency band has been split into single test frequencies in order to find its starting point (SP) as a signal free (quiet) zone. Computing some features of the signal the sound will be distinguishable from the disturbing signals as hiccups, body's rotation and limb movements or even additional noises of maternal heart beats. The SPs of the episodes are characterized by an approximation process in order to select the real ones.Clinical relevance- The method is an irradiation free measurement, carried out on the maternal abdomen. Furthermore, connected with the fetal phonocardiographic (fPCG) monitoring the method offers a non-invasive way for FBM detection applicable also at home. More than 50 pregnancies were examined with the proposed method for at least for 20-min with synchronous measurements by the proposed phonographic device and a 3D ultrasound machine in the third trimester.

Automatic identification of fetal breathing movements in fetal RR interval time series

Fetal breathing movements are associated with respiratory sinus arrhythmia (RSA). We present an algorithm which processes RR interval time series in the time and frequency domain, identifying spectral peaks with characteristics consistent with fetal RSA. Tested on 50 data sets from the second and third trimester, the algorithm had a sensitivity of 96.1%, false positive rate 35.7%, false negative rate 3.9%. The characteristics of automatically and visually identified episodes were very similar and corresponded the expected changes over gestation. The method is suited for easy and reliable identification of fetal breathing movements.

Behavior of pulmonary venous flow during fetal respiratory movements

OBJECTIVE

To test the hypothesis that fetal pulmonary venous flow pulsatility index is lower during fetal respiratory movements than in apnea.

DESIGN

Case control. SETTINGS/PATIENTS: Twenty-two normal fetuses of mothers without systemic disease were examined in apnea (controls) and in the presence of fetal respiratory movements (cases). Fetuses were examined by prenatal Doppler echocardiography with color flow mapping. The pulsatility index of the pulmonary vein was obtained by placing the pulsed Doppler sample volume over the right upper or left lower pulmonary vein, and calculating the ratio (maximum velocity [systolic or diastolic]-presystolic velocity/mean velocity).

RESULTS

Mean gestational age was 28.9 +/- 2.9 weeks. During fetal apnea, mean systolic, diastolic, and presystolic velocities were, respectively, 0.35 +/- 0.08 m/s, 0.26 +/- 0.07 m/s, and 0.09 +/- 0.03 m/s. In the presence of fetal respiratory movements, mean systolic, diastolic, and presystolic velocities were, respectively, 0.33 +/- 0.1 m/s, 0.28 +/- 0.08 m/s, and 0.11 +/- 0.04 m/s. Pulsatility index pulmonary vein in apnea was 1.25 +/- 0.23 (1.69 to 0.82), and during fetal respiratory movements it was 0.97 +/- 0.2 (1.53 to 0.61).

CONCLUSION

We showed a significant reduction in impedance of pulmonary venous flow, represented by pulmonary vein pulsatility index, during fetal respiratory movements, reflecting modifications of the left atrial dynamics and enhancement of left ventricular compliance.

Photogrammetry of fetal breathing movements during the third trimester of pregnancy: observations in normal and abnormal pregnancies

OBJECTIVE

To evaluate parameters of fetal breathing movements-displacement of the fetal abdominal wall during inspiration and expiration, time of inspiration and expiration and speed of inspiration and expiration-between 30 and 36 weeks' gestation in normal pregnancies, and in those complicated by gestational diabetes or maternal hypertension.

METHODS

Three categories of pregnancy were investigated: 49 were normal, 16 had pregnancy-induced diabetes and 10 were hypertensive. According to their gestational age, the patients were divided into two groups: Group A between 30 and 32 weeks' gestation and Group B between 33 and 36 weeks. Using photogrammetry and a computer-operated algorithm, six parameters of fetal breathing movements were investigated.

RESULTS

There were significant differences in the various fetal parameters measured among the three categories of pregnant women. Up until 32 weeks of gestation, the displacements during inspiration and expiration were larger, the speeds of inspiration and expiration were higher, and the times for inspiration and expiration were shorter in the diabetic and hypertensive groups than in the normal group. In the later period, between 33 and 36 weeks, fetuses of pregnancy-induced diabetic patients showed the lowest inspiration and expiration times and the highest speeds of inspiration and expiration.

CONCLUSIONS

Photogrammetry in conjunction with a computer-operated algorithm can be used to assess fetal breathing movements. There are significant differences in fetal breathing movements between normal pregnancies and those that are complicated by gestational diabetes or hypertension.

Scaling analysis of paces of fetal breathing, gross-body and extremity movements

Using detrended fluctuation analysis (DFA), we studied the scaling properties of the time instances (occurrence) of the fetal breathing, gross-body, and extremity movements scored on a second by second basis from the recorded ultrasound measurements of 49 fetuses. The DFA exponent α of all the three movements of the fetuses varied between 0.63 and 1.1. We found an increase in α obtained for the movement due to breathing as a function of the gestational age while this trend was not observed for gross-body and extremity movements. This trend was argued as the indication of the maturation of lung and functional development of respiratory aspect of the fetal central nervous system. This result may be useful in discriminating normal fetuses from high-risk fetuses.

Maternal breath-holding and the valsalva maneuver: methods to overcome fetal breathing movements during Doppler sonography

Fetal breathing movements (FBM) hinder Doppler measurements in the fetus. The aim of the present study was to establish whether FBM are overcome by the mother holding her breath for a few seconds or performing the Valsalva maneuver (VM). This prospective study included a group of 120 consecutive patients showing FBM. In 78 patients (65%), FBM were observed only at the beginning of the examination and then stopped spontaneously. In the other 42 patients, FBM were still present during and at the end of the general examination. These patients were considered for the evaluation. In a first step, the mother was asked to hold her breath for 5 s. If FBM continued, the procedure was repeated. If this also failed, the Valsalva maneuver was performed. In the presence of fetal apnea, flow velocity measurements were taken from the umbilical artery. Nine patients (21%) halted FBM with the first attempt at maternal breath-holding, four patients (10%) with the second attempt and 22 patients (52%) on using the VM. FBM was arrested within a maximum of 94 s after breath-holding or the VM. No reaction to any of the procedures was observed in seven patients (17%). Breath-holding alone or in combination with the Valsalva maneuver has been shown to be effective in overcoming the problem of FBM during prenatal Doppler examination in most cases.