Biomedical subjects

M Pillai

Publications and source records attributed to M Pillai.

23 records · Page 2Linked to original sources

PubMed1990

The development of fetal heart rate patterns during normal pregnancy.

Characteristics of the fetal heart rate (FHR) were studied longitudinally throughout the second and third trimesters in 43 low-risk singleton fetuses. The second trimester was characterized by an FHR pattern showing minimal differences between quiet and active intervals of fetal behavior. Few movements were accompanied by accelerations of small magnitude. Brief decelerations of variable magnitude exceeded the number of accelerations, and their frequency declined with advancing maturity. The percentage of body movements accompanied by FHR acceleration, the amplitude of these accelerations, and the rate of rise in heart rate increased with gestational age. Up to 30 weeks, the characteristics of the baseline FHR were similar in both periods of fetal rest and activity, with the baseline variability becoming significantly greater with advancing gestation. However, during quiet cycles of fetal behavior after 30 weeks, the baseline variability became progressively narrower, so that in late pregnancy different behavioral states could be determined reliably from characteristics of the baseline FHR alone.

Embryonic and Fetal Development↗

PubMed1990

The importance of the behavioural state in biophysical assessment of the term human fetus.

We have examined how the different behavioural states exhibited by 78 healthy fetuses at term influence the result of the non-stress test (NST) and biophysical profile score (BPS). In association with state 1F the average recording time to obtain a satisfactory NST and BPS was 27.0 and 26.3 min respectively, and 52.6% and 44.0% respectively failed to achieve a 'normal' result. In contrast, satisfactory results were always obtained in the two active states (2F and 4F), and the average time was 3-5 min. Mature fetuses spend on average one third of the time in state 1F, and knowledge of its characteristics is therefore important, for the interpretation of biophysical tests. Our results suggest that continuation of biophysical recording for at least 40 min is necessary before an unreactive NST or low BPS should be regarded as suspicious. We suggest that interpretation of the NST and BPS should be made in the light of knowledge of normal patterns of behavioural development rather than using an arbitrarily defined scoring system.

Amniotic Fluid↗

PubMed1990

Hiccups and breathing in human fetuses.

Serial recording in 45 low risk fetuses throughout the second and third trimesters showed that hiccups were the predominant diaphragmatic movement before 26 weeks' gestational age and that there was a significant negative correlation with gestational age. There was a pronounced reduction between 24 and 26 weeks, which was the result of a decrease in the number of episodes of hiccups rather than a change in the duration of episodes. In contrast, fetal breathing was positively correlated with gestational age, the greatest increase in breathing occurring between 26 and 32 weeks' gestation. This was the result of both an increase in the number and duration of episodes. From the time that rest-activity cycles of behaviour could be determined in recordings, both breathing and hiccups were dependent on behavioural state or cycle, occurring predominantly during active episodes. This association between quiet and active behaviour and breathing did not alter with increasing gestational age, and the variables in fetal behavioural state became increasingly closely linked. The importance of prolonged and repeated recording, and also the need to take account of other variables in fetal behaviour, before any sinister conclusions can be drawn about the absence of fetal breathing is emphasised.

Diaphragm↗

PubMed1990

Behavioural states in normal mature human fetuses.

Behaviour was studied by real time ultrasound in a group of 80 low risk fetuses between 36 and 42 weeks' gestation. There was close linkage of fetal eye movements, somatic movements and heart rate pattern reflecting three different states. Quiescence (state 1F) was characterised by no eye movements, no somatic movements except for the occasional startle, and a fetal heart rate pattern with little baseline variability. There were two active states: state 2F characterised by continuous eye movements, frequent bursts of somatic movements, and wide baseline variability with accelerations with movement, and state 4F characterised by continuous eye movements with almost continuous somatic movements and a sustained tachycardia. These fulfilled criteria for three of four behavioural states previously described in human fetuses. Cycling of quiescent and active states occurred in 77 (96%) of the fetuses within 100 minutes of starting the recording. 2F was the commonest behavioural state, being seen 58% of the time. 1F was seen 30% of the time, and 4F 9% of the time. During the remaining 3% of observation time the behavioural state was indeterminate.

Eye Movements↗

PubMed1990

Development of human fetal behavior: a review.

Most of the movements described during the course of gestation have already emerged before 16 weeks, and the presence of diurnal variation in human fetal behavior has been demonstrated from as early as 20 weeks gestation. Up to 26 weeks quiet intervals rarely exceed 5 min. After this age quiet intervals progressively increase in duration so that behavior appears cyclically rather than randomly distributed. Increasing linkage of the state variables results in identifiable fetal behavioral states from around 36 weeks. During the last trimester fetal activities are cycle- or state-dependent, so that prolonged, and often repeated, recording of behavior is necessary before any sinister conclusions can be drawn.

Circadian Rhythm↗