Maternal zinc supplementation during pregnancy affects autonomic function of Peruvian children assessed at 54 months of age.

Maternal prenatal zinc supplementation improved fetal autonomic regulation in a nutrient-deficient population in Peru. To evaluate whether differences in autonomic regulation existed in early childhood, we studied 165 children from a zinc supplementation trial (80% of original sample) as part of a comprehensive evaluation at age 54 mo. Electrocardiogram (ECG) data were collected from the children at rest and while they underwent a cognitive testing battery following a standardized protocol. Of these, 79 were born to mothers receiving 25 mg/d zinc in addition to 60 mg/d iron and 250 µg/d folic acid during pregnancy, and 86 were born to mothers receiving iron and folic acid only. Derived cardiac measures included heart period (HP), range, HP variability (HPV), mean square of successive differences (MSSD), and a measure of vagal tone (V). Children in the zinc supplementation group had greater HP (i.e. slower heart rate), greater range, higher time-independent (HPV) and time-dependent (MSSD) variability in HP, and higher V (P < 0.05) during baseline. Analyses conducted across the cognitive testing period revealed similar effects of prenatal zinc supplementation on cardiac patterns. Concurrent child zinc plasma concentration was also associated with longer HP, greater variability, and marginally higher range and V (P < 0.10). Differences in cardiac patterns due to prenatal zinc supplementation were detectable in children at 54 mo of age during conditions of both rest and challenge, indicating that supplementing zinc-deficient pregnant women has beneficial long-term consequences for neural development associated with autonomic regulation.

Maternal gestational zinc supplementation does not influence multiple aspects of child development at 54 mo of age in Peru.

BACKGROUND: Zinc is necessary for central nervous system development, and maternal zinc status has been associated with developmental differences in offspring. OBJECTIVE: The objective was to evaluate differences in cognitive, social, and behavioral function in Peruvian children at 54 mo of age whose mothers participated during pregnancy in a zinc supplementation trial. DESIGN: We attempted to follow up 205 children from a prenatal zinc supplementation trial and present data on 184 (90%) children-86 whose mothers took 25 mg zinc/d in addition to 60 mg iron and 250 microg folic acid and 98 whose mothers took iron and folic acid only. Following a standardized protocol, we assessed children's intelligence, language and number skills, representational ability, interpersonal understanding, and adaptive behavior and behavioral adjustment. We also assessed aspects of the mother (eg, age, education, verbal intelligence, stresses, and social support in parenting) and the home environment [HOME (Home Observation for the Measurement of the Environment) inventory]. RESULTS: No differences were observed between any of the tests used to characterize cognitive, social, or behavioral development (P > 0.05). Child sex, parity, or treatment compliance did not modify the effects of supplementation on any outcomes. CONCLUSION: The addition of zinc to prenatal supplements did not influence developmental outcomes in Peruvian children when assessed at 4.5 y of age.

Nutritional influences on maternal autonomic function during pregnancy.

The objective of this study was to identify influences on longitudinal changes in autonomic function during pregnancy. We studied 195 low-income Peruvian women who were subjects in a randomized controlled trial of zinc supplementation and fetal neurobehavioral development. Maternal cardiorespiratory status and electrodermal activity were assessed at 20, 24, 28, 32, 36, and 38 weeks' gestation over a 50-min session. At baseline (10-16 weeks), and at 28 and 36 weeks' gestation, mass and height, arm and calf circumferences, and skinfold thicknesses were assessed, and blood was taken to measure hemoglobin, hematocrit, and plasma zinc concentration. Measures of heart period (HP), respiratory period (RP), respiratory sinus arrhythmia (RSA), skin conductance level (SCL), and mean arterial pressure (MAP) were analyzed using longitudinal models. Having a hemoglobin concentration <10.5 g.dL-1 at 28 weeks was associated with shorter HP and RP and lower RSA, and change in hemoglobin from baseline to 36 weeks was associated with decreased SCL. Further, 3 measures were associated with variation in fat or fat-free mass in the calf; RSA was negatively associated with changes in calf muscle area over pregnancy, while changes in calf fat area were positively associated with MAP and SCL. Variability in autonomic function during the second half of pregnancy is associated with hematologic status and changes in lower limb body composition across pregnancy.

Prenatal development of intrafetal and maternal-fetal synchrony.

Fetal and maternal data were monitored serially at 6 gestational ages from 20 to 38 weeks in 195 Peruvian fetuses. Digitized data included fetal heart rate and motor activity, as well as maternal heart rate and electrodermal conductance. Time series analysis evaluated the development of synchrony in 2 streams of fetal functioning and between mothers and fetuses. Intrafetal synchrony between heart rate and motor activity developed in an orderly fashion, with peak cross-correlation approaching an asymptote at 5 s at 28 weeks. Synchrony was not observed between fetal heart rate and maternal measures. Fetal motor activity exhibited synchrony with both maternal electrodermal and heart rate activity. Implications for revealing fundamental properties of neural development prior to birth are discussed.

Fetal neurobehavioral development: a tale of two cities.

Longitudinal neurobehavioral development was examined in 237 fetuses of low-risk pregnancies from 2 distinct populations--Baltimore, Maryland, and Lima. Peru--at 20, 24, 28, 32, 36, and 38 weeks gestation. Data were based on digitized Doppler-based fetal heart rate (FHR) and fetal movement (FM). In both groups. FHR declined while variability, episodic accelerations, and FM-FHR coupling increased, with discontinuities evident between 28 and 32 weeks gestation. Fetuses in Lima had higher FHR and lower variability, accelerations, and FM-FHR coupling. Declines in trajectories were typically observed 1 month sooner in Lima, which magnified these disparities. Motor activity differences were less consistent. No sex differences in fetal neurobehaviors were detected. It is concluded that population factors can influence the developmental niche of the fetus.

Randomized controlled trial of prenatal zinc supplementation and fetal bone growth.

BACKGROUND: Maternal zinc deficiency is relatively common in developing countries, but its consequences for fetal growth are not established. OBJECTIVE: The goal was to examine whether improvement in maternal gestational zinc status is positively associated with fetal growth as assessed by ultrasonography. DESIGN: We conducted a double-masked, randomized trial among 242 pregnant Peruvian women in an impoverished shantytown in Lima, Peru. At 10-16 wk of gestation, the women were randomly assigned to receive daily supplements containing 60 mg Fe and 250 microg folic acid, with or without 25 mg Zn. We measured fetal head circumference, biparietal diameter, abdominal circumference, and femur diaphysis length at 20, 24, 28, 32, 36, and 38 wk of gestation. Fetal measures were analyzed longitudinally to evaluate differences in trends of fetal growth by supplement type, and within-subject correlations were taken into account. RESULTS: Femur diaphysis length was greater in fetuses whose mothers received zinc supplements (P < 0.05), and the difference tended to increase with gestational age. No significant differences by supplement type were observed for the other anatomical sites measured. CONCLUSIONS: The observed positive effect of prenatal zinc on fetal femur diaphysis length is consistent with the results of experimental studies in animals and in vitro. The supplementation effect represents an upward shift in mean femur diaphysis length at term of about one-quarter of the reference SD. These findings suggest the potential importance of maternal zinc status for fetal bone growth in humans and illustrate the value of ultrasonography for evaluating the effect of prenatal nutritional interventions on components of fetal growth.