Majid Mirmiran

PHYSIOLOGICAL EFFECTS OF KANGAROO CARE IN VERY SMALL PRETERM INFANTS

Kangaroo care for preterm infants has great benefits for the parents and for the parent-infant bonding process. A clinical observational study was conducted in which several physiological variables were collected, including among others transcutaneous oxygen pressure, heart rate, respiratory rate, occurrence of apneic attacks, breathing pattern (studied with power spectrum analysis), behavioral states and rectal temperature, during kangaroo care in small preterm infants. Kangaroo-care did not significantly affect any of these physiological variables comparing the period of 1 h before, 1 h during and 1 h after kangaroo care. We conclude that kangaroo care is a safe method, even for very small nonstabilized preterm infants.

Fetal and maternal diurnal rhythms during the third trimester of normal pregnancy : Outcomes of computerized analysis of continuous twenty-four-hour fetal heart rate recordings

OBJECTIVE We quantified the presence of diurnal rhythms in various computerized fetal heart rate parameters in normal pregnancies to assess their clinical relevance. STUDY DESIGN Modified cosine analysis was applied to the outcomes of computerized analysis of continuous 24-hour fetal heart rate recordings in 26 normal pregnancies. Diurnal rhythms in maternal heart rate and plasma hormones were assessed in 15 and 17 pregnancies, respectively. Correlations between maternal and fetal rhythms were calculated. RESULTS A significant diurnal rhythm in basal heart rate was present in 73% of the fetuses and was closely related to the maternal heart rate rhythm. Diurnal rhythms in heart rate variability, accelerations, and activity were present in only 30% to 50% of the fetuses. CONCLUSIONS The mother entrains fetal diurnal rhythms. The normal variability in neural development may account for the absence of diurnal rhythms in some fetuses.

Movement, imaging and neurobehavioral assessment as predictors of cerebral palsy in preterm infants.

Objective:To study the relative efficacy of three early predictors of cerebral palsy.Method:One Hundred and thirty infants with birth weight <1500 g were recruited. Video recordings of spontaneous general movements were made at 36 and 52 weeks postconceptional age. Magnetic resonance imaging and the neurobehavioral assessment of the preterm infant were done at 36 weeks postconceptional age. Follow-up neurological examination and Bayley assessments were made at 18 months corrected age to make early identification of cerebral palsy.Results:Magnetic resonance imaging gave the best specificity and accuracy of 91 and 84% respectively. General movements at 52 weeks showed an improved specificity and accuracy over performance at 36 weeks postconceptional age. The negative predictive value for all methods tested was between 90 and 97%. Combining the results of magnetic resonance imaging and the neurobehavioral assessment improved the sensitivity of prediction to 80%, suggesting that a holistic approach to early detection of cerebral lesions is preferable to a single test.Conclusions:The majority of infants who appeared to behave within normal limits and exhibit normal brain structure in the newborn period were classified as neurologically intact at follow-up.

Chapter 15 Perinatal development of human circadian rhythms

The early development of circadian rhythms in primates, including man, was reviewed. Continuous 24-h recordings were carried out for maternal and fetal circadian rhythms during gestation as well as in preterm infants. Several propositions were made based on these new findings: 1. The fetal biological clock is an endogenous clock capable of generating circadian rhythms and responding to maternal entraining signals long before the moment of birth. 2. Through the fetal biological clock, maternal circadian rhythms influence the fetal overt rhythms. 3. Maternal rhythms influence the fetus, and fetal rhythms feed back to the mother (via the placenta). Disruption of this fetal-maternal interaction during gestation leads to: a. disturbances of maternal and fetal circadian rhythms; b. disappearance of circadian rhythms at the time of birth; c. a gestational period which is either too short or too long (see also Honnebier and Swaab, 1973); d. delayed or impaired maturation of the circadian rhythms of the infant.

Circadian and Sleep Development in Preterm Infants Occurs Independently From the Influences of Environmental Lighting

This study investigated the effect of intermediate nursery illumination on circadian rhythm and sleep development of preterm infants. Preterm infants were randomly assigned to one of two intermediate nursery rooms: a dimly lighted room, the dim (control) group, or a day-night lighted room, the cycled (intervention) group. Continuous rectal temperature and sleep were recorded at 36 wk postconceptional age (before discharge) and at 1 and 3 mo corrected age at home. Forty infants, 21 in the dim group and 19 in the cycled group, were recorded. The clinical demographic data and neonatal scores were similar between groups before the intervention. Circadian rhythms and sleep showed significant development with age, but there was no environmental lighting effect. Circadian and sleep organization seems to develop endogenously in preterm infants.

Neurobehavioral assessment predicts differential outcome between VLBW and ELBW preterm infants

OBJECTIVE:To evaluate the impact of birth weight on development of very low birth weight (VLBW) infants using the Neurobehavioral Assessment of the Preterm Infant (NAPI) before hospital discharge, and to show the relation to follow-up outcomes at 12, 18 and 30 months of age.STUDY DESIGN:In total, 113 preterm infants were assessed with the NAPI at 36 weeks postmenstrual age. Later, neurodevelopment was examined using the Bayley Infant Neurodevelopmental Screener (BINS) at 12 months and the Bayley Scales of Infant Development, at 18 and 30 months. The cohort was divided into two groups, based on birth weight, extremely low birth weight (ELBW) (<1000 g) and VLBW (1000 to 1500 g).RESULTS:ELBW infants showed significantly lower NAPI scores compared with VLBW infants at 36 weeks. The predischarge NAPI scores correlated with the 12, 18 and 30 months scores when the ELBW infants continue to have lower performance than the VLBW infants. In all, 14 infants developed cerebral palsy. These infants had significantly lower NAPI, BINS and Bayley scores compared with all other preterm infants.CONCLUSION:NAPI before discharge provides clinically meaningful information related to later neurodevelopmental outcome.

Can magnetic resonance spectroscopy predict neurodevelopmental outcome in very low birth weight preterm infants

Objective:To determine if metabolite ratios at near-term age predict outcome in very low birth weight preterm infants at 18 to 24 months adjusted age.Study Design:Thirty-six infants (birth weight ⩽1510 g, gestational age ⩽32 weeks) were scanned at a postmenstrual age (PMA) of 35 to 43 weeks from July 2001 to September 2003. Multivoxel proton spectroscopic data were acquired and metabolite ratios were calculated in regions of the thalamus and basal ganglia. Bayley Scales of Infant Development were assessed between 18 and 24 months corrected age.Result:Metabolic ratios showed no significant correlation with developmental outcome. A correlation was seen between N-acetylaspartate (NAA)/choline (Ch) and PMA in thalamus and basal ganglia.Conclusion:Metabolite ratios from near-term proton magnetic resonance spectroscopy (MRS) were not predictive of Bayley scores at 18 to 24 months adjusted age. There was a positive correlation between NAA/Ch and PMA, which supports previous work by others for the importance of developmental changes in the MRS with age.

Fewer spontaneous arousals during prone sleep in preterm infants at 1 and 3 months corrected age

Objective:This study was performed to determine if there were fewer spontaneous arousals in prone sleep than in supine sleep.Study design:Home polysomnography/video recordings were done during daytime naps in 14 preterm infants: four at corrected age of 1 month, nine at both 1 and 3 months, and one only at 3 month. A body movement lasting 3 to 60 s during sleep was used as an indicator of spontaneous arousals.Results:Most arousals had a heart rate increase and change in respiration pattern. The mean duration of the intervals between successive arousals in active and quiet sleep was significantly longer in prone at 1 and 3 months of age. The duration of arousals was significantly shorter at 3 months corrected age compared with one month corrected age during active sleep. The duration of arousals was shorter during quiet sleep at one month compared with active sleep.Conclusion:There were fewer spontaneous arousals that is, longer interval between successive arousals in prone, which may, in part, explain the increase in risk of Sudden Infant Death Syndrome.

Development of macronutrient composition of very preterm human milk

The effects of gestational age at delivery (GA), postnatal age (PNA) and post-menstrual age (PMA = PNA + GA, an indicator of autonomous developmental processes not affected by the moment of birth) on macronutrient composition of very preterm milk were studied. Total N, fat, lactose and carbohydrate concentrations, energy density and 24 h volume were determined in 282 24 h milk samples collected at weekly intervals (days 7-55 of lactation) from seventy-nine women delivering their babies between 25 and 29 weeks of gestation. GA related differences were found for carbohydrate concentration only: carbohydrate concentration was lower with increasing GA. PNA was related to a decrease in total N and an increase in lactose concentration. PMA was not related to milk composition. Our data indicate that PNA strongly influences the development of the composition of very preterm human milk, while GA affects carbohydrate content with a negligible effect on the nutritional value of the milk. We conclude that in accordance with current opinion in paediatrics, human milk is the best source of nutrients even for very preterm (< 30 weeks GA) infants.

Effects of prone and supine position on sleep characteristics in preterm infants

The purpose of this study was to address the influence of sleep position on sleep characteristics in preterm infants. We studied 16 infants at a mean post‐conceptional age of 36.5 weeks. Infants were successfully recorded with videopolysomnograph in the supine and prone position. Between the two positions, there were no significant differences in percentage of active sleep and quiet sleep (QS), the occurrence of arousal, and the incidence of apnea. The first QS after the feeding was longer in the prone position. The sleep position could affect sleep characteristics but not respiratory characteristics in preterm infants.