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PubMed1992

Maternal hypothyroxinemia and brain development: I. A hypothetical control system governing fetal exposure to maternal thyroid hormones.

Maternal hypothyroxinemia consequent on endemic iodine deficiency is associated with an increased incidence of neurological disorders in the offspring. Such correlations were originally postulated as reflecting direct effects of elemental iodine on fetal brain development during early pregnancy, it being generally believed that maternal thyroid hormones do not cross the placenta in significant amount in consequence of the presence of elevated concentrations of TBG in maternal blood. However TBG possesses the capacity to enhance T4 transport to particular target organs during pregnancy. This realization led us to hypothesize a) that maternal T4 is transported to the fetus, and is of crucial importance to early fetal development, and b) that TBG forms part of a control system specifically designed to maintain at an optimal level the T4 environment to which the developing fetus is exposed. Subsequent studies in rats demonstrated that maternal T4 traverses the placenta in significant amounts prior to the development of the fetal thyroid. Other studies have led us to suggest that one or more isoforms of HCG may be implicated in a feed-back system interacting with the hypothalamic/pituitary system governing maternal thyroid hormone secretion. Though our experimental work has primarily focused on the effects of thyroid hormones on the fetal brain, we believe it to be likely that fetal exposure to maternal hormones is under placental control, and that other components of this putative system are worthy of study.

Animals↗
PubMed1995

[Impact of the introduction of a partogram on maternal and perinatal mortality. Study performed in a maternity clinic in Niameny, Niger].

Maternal mortality remains one of the major problems in public health today especially in developing countries where maternal mortality is estimated to be between 500 and 1000 deaths for 100,000 live births. In 1987, the safe motherhood initiative was launched with the objective of reducing maternal mortality by 50% within ten years. One of the methods introduced to reduce the high incidence of maternal and neonatal mortality in developing countries, is the partogram, a visual means used in evaluating a normal delivery. It acts as an early warning system, allowing for the early detection of abnormal evolution in labour as well for the mother as for the foetus. This instrument was introduced in all the maternity wards in Niger in 1990 by the Ministry of Public Health. A study was conducted in one of the maternities of the capital to ascertain the effectiveness of this new instrument to both the mother during labor and the newborn child. 1299 women in labor, primi-and multiparous, participated in the study. Two groups were formed: one consisted of women that delivered prior to the introduction of the partogram, the second group was comprised of women who delivered after its introduction. The results of this study have shown that the introduction of the partogram: reduces the amount of time that a women is in labor, improves the follow-up care the pregnant woman receives, results in a more timely decision made by the health official, and consequently, a prompt referral to a specialised center. The authors estimate that, if used correctly, the introduction of this instrument can have along with other appropriate measures, a considerable impact in the reduction of maternal and neonatal mortality.

Adult↗
PubMed2000

Maternal oxygen administration for suspected impaired fetal growth.

BACKGROUND: Fetal hypoxaemia is often a feature of fetal growth impairment. It has been suggested that perinatal outcome after suspected impaired fetal growth might be improved by giving mothers continuous oxygen until delivery. OBJECTIVES: The objective was to assess the effects of maternal oxygen therapy in suspected impaired fetal growth on fetal growth and perinatal outcome. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Controlled Trials Register. SELECTION CRITERIA: Acceptably controlled trials comparing maternal oxygen therapy with no oxygen therapy in suspected impaired fetal growth. DATA COLLECTION AND ANALYSIS: Eligibility and trial quality was assessed. MAIN RESULTS: Two studies involving 62 women were included. Oxygenation compared with no oxygenation was associated with a lower perinatal mortality rate (relative risk 0.41, 95% confidence interval 0.21 to 0.78). However higher gestational age in the oxygenation groups may have accounted for the difference in mortality rates. REVIEWER'S CONCLUSIONS: There is not enough evidence to evaluate the benefits and risks of maternal oxygen therapy for suspected impaired fetal growth.

Female↗
PubMed1992

Ovine maternal and fetal renal vasopressin receptor response to maternal dehydration.

OBJECTIVE: Arginine vasopressin secretion increases in response to increased plasma osmolality or hypovolemia. Dehydration-induced increases in plasma arginine vasopressin levels have been shown to down-regulate arginine vasopressin V2 receptors in adult rat kidneys. Our study determined ovine maternal and fetal renal arginine vasopressin receptor characteristics and receptor response to maternal dehydration. STUDY DESIGN: Eight pregnant ewes (113 +/- 1 days) were dehydrated for 72 hours; eight animals served as controls. Renal medullary tissue was isolated from maternal and fetal kidneys, and arginine vasopressin receptor characteristics determined with saturation and competition assays using tritiated arginine vasopressin, arginine vasopressin, and arginine vasopressin analogs. RESULTS: Euhydrated maternal and fetal renal medullary arginine vasopressin receptor dissociation constant (3.0 +/- 0.3 and 1.9 +/- 0.3 nmol/L) and maximal binding capacity (149 +/- 15 and 111 +/- 33 fmol/mg protein) values were similar. Pharmacologic profiles with selective agonists indicated a predominance of V2 receptors. Dehydration significantly increased maternal and fetal plasma osmolalities (304 +/- 2 to 320 +/- 2; 296 +/- 1 to 319 +/- 3 mOsm/kg water, respectively) and arginine vasopressin levels (3.8 +/- 1.4 to 29.3 +/- 4.6; 4.4 +/- 1.0 to 16.9 +/- 5.0 pg/ml, respectively) but had no effect on arginine vasopressin receptor binding. CONCLUSION: Specific, saturable, single-site tritiated arginine vasopressin binding is present in ovine maternal and fetal renal medullary membranes. Ovine maternal and fetal renal arginine vasopressin receptors do not down-regulate in response to dehydration-induced elevations in plasma arginine vasopressin levels.

Animals↗
PubMed2006

Maternal N-acetylcysteine suppresses fetal inflammatory cytokine responses to maternal lipopolysaccharide.

OBJECTIVE: Evidence suggests that maternal infections may induce fetal inflammatory responses. Because cytokine actions may be mediated by oxidative stress, we determined whether N-acetylcysteine, an antioxidant, can blunt fetal inflammatory responses to maternal lipopolysaccharide. STUDY DESIGN: Sprague Dawley near-term rats (n = 16) received intraperitoneal lipopolysaccharide (100 microg/kg) at 30 minutes and saline solution or N-acetylcysteine (300 mg/kg) at 150 minutes. An additional group received N-acetylcysteine before and after lipopolysaccharide administration. At 6 hours, rats were killed, and fetal and maternal blood cytokines were determined. RESULTS: After maternal lipopolysaccharide administration, fetal blood interleukin-6 markedly increased (3 +/- 2 to 1265 +/- 574 pg/mL); N-acetylcysteine that was given before or before and after lipopolysaccharide administration reduced fetal interleukin-6 response to control levels. A similar trend was observed for interleukin-1beta. No effect of N-acetylcysteine on fetal interleukin-10 levels was observed. CONCLUSION: Maternal N-acetylcysteine inhibits fetal cytokine responses to maternal lipopolysaccharide, even when given 2 hours after lipopolysaccharide injection. These results suggest that N-acetylcysteine may protect the fetus from sequelae of maternal inflammation.

Acetylcysteine↗
PubMed1996

Maternal concentrations and fetal-maternal concentration differences of plasma amino acids in normal and intrauterine growth-restricted pregnancies.

OBJECTIVES: Our purpose was to determine whether maternal amino acid concentration changes during gestation in pregnancies with intrauterine growth restriction as in normal pregnancies and to verify whether these changes are related to changes in fetal-maternal differences. STUDY DESIGN: Amino acid concentrations were measured in 5 nonpregnant women, in 11 second-trimester and 10 third-trimester pregnant women with appropriate-for-gestational-age fetuses, and in 23 pregnant women with intrauterine growth restriction. Umbilical venous amino acids were measured at the time of fetal blood sampling. The severity of intrauterine growth restriction was assessed by Doppler velocimetry and fetal heart rate and by evaluation of oxygenation and acid-base balance. RESULTS: In normal pregnant women the maternal concentration of most amino acids was significantly lower in both the second and third trimesters compared with nonpregnant women. In intrauterine growth restriction the maternal concentrations of most essential amino acids were significantly higher than in appropriate-for-gestational-age pregnancies. This observation, coupled with lower fetal amino acid concentrations in intrauterine growth restriction, leads to significantly lower fetal-maternal differences. CONCLUSIONS: Normal pregnant women have a significant decrease in amino acid concentrations compared with nonpregnant women, whereas in intrauterine growth restriction maternal amino acids are reduced less, Significantly lower fetal-maternal concentration differences are present in intrauterine growth restriction, independent of the degree of severity.

Adult↗
PubMed1995

Continuous maternal glucose infusion during labor: effects on maternal and fetal glucose and lactate levels.

Fetal and neonatal glucose and lactate levels and acid-base balance after continuous maternal infusion of 5% dextrose at 180 mL/h (9 g/h) was compared with 0.9% saline solution in a prospective, randomized study from selected monitored labors. An infusion of 5% dextrose produced significantly increased glucose levels in maternal (p < 0.01), cord artery (p < 0.01), and cord vein (p < 0.001) blood. An increased maternal insulin level was also present (p < 0.05), but no differences in cord insulin levels were observed. beta-Hydroxybutyrate was lower in maternal (p < 0.05) and cord vein (p < 0.01), but not in cord artery blood, after maternal dextrose infusion. No significant changes occurred in blood lactate levels between the two groups in either mother, fetus, cord, or neonate. Acid-base balance in cord blood did not differ between the two groups. Maternal infusion of 5% dextrose at 180 mL/h (9 g/h), compared with saline solution, produces higher glucose levels in both mother and fetus, but increased insulin concentrations only in the mother. Dextrose infusion also lowers beta-hydroxybutyrate in maternal and cord vein blood. No differences were seen in lactate levels or cord acid-base balance. Both regimens seem safe according to risks for lactacidosis and neonatal hypoglycemia in the normoxemic, normal size fetus.

3-Hydroxybutyric Acid↗
PubMed2004

Maternal dominance, maternal condition, and offspring sex ratio in ungulate mammals.

Trivers and Willard's suggestion that natural selection favors maternal control of offspring sex ratio in relation to maternal condition has been much debated. The theoretical plausibility of the idea, under some conditions, is firmly established, and there is strong empirical support for conditional sex allocation in some taxa. However, the extent to which this hypothesis can be applied to mammals, particularly ungulates, has been more controversial. We used meta-analysis to review published studies of the Trivers-Willard hypothesis within ungulates and to assess the overall level of empirical support for the hypothesis. Overall, data from 37 studies of 18 species suggested a weak but significant positive correlation between maternal condition and sex ratio (r=+0.09). However, average effect size differed markedly between different categories of studies. Studies using measures of maternal condition that were taken preconception and on the basis of behavioral dominance provided strong evidence for a relationship between maternal condition and the sex ratio (r=+0.17-0.25). In contrast, studies that used morphological or physiological measures of condition that were measured postconception provided little or no evidence for a relationship between maternal condition and sex ratio (r=+0.05-0.06). There are several reasons to suggest that data collected postconception and relying on morphological measures of condition are less likely to capture variables that cause selection for biased sex allocation. In addition, we found that the relationship between sex ratio and maternal condition depended on life-history characteristics; relationships were stronger when sexual size dimorphism was more male biased and when gestation periods were longer. Overall, our analyses suggest that data from ungulates are consistent with the Trivers-Willard hypothesis but only when appropriate measures are used.

Animals↗
PubMed2003

LD mapping of maternally and non-maternally derived alleles and atopy in FcepsilonRI-beta.

Polymorphisms in the beta chain of the high affinity receptor for IgE (Fc epsilon RI-beta, MS4A2) are consistently associated with traits underlying asthma and atopy (immunoglobulin E-mediated allergy). However, the causal variants and haplotypes underlying disease have not yet been identified. Maternal effects, with association confined to maternally derived alleles, have been shown in some studies but not in others. We have therefore extended the known sequence and systematically detected polymorphisms across an 18.1 Kb genomic region that includes Fc epsilon RI-beta. Association testing in two panels of subjects showed the presence of single-nucleotide polymorphisms (SNPs) affecting prick skin tests and specific IgE responses in several clusters. Stepwise analyses indicated that the clusters represent independent effects. Interferon regulatory factor 2 (IRF-2) sites were altered by significantly associated SNPs in two regions. Strong association to maternally derived alleles was seen in one panel of subjects and not in the other. Maternal and non-maternally derived associations tended to share the same SNP clusters, but associations were stronger in the presence of maternal effects. Two regions of increased CpG concentration were identified in Fc epsilon RI-beta. One of these approximated a SNP cluster that showed strong association and maternal effects, providing a potential substrate for epigenetic effects.

Alleles↗
PubMedDate not supplied

Maternal effects and the evolution of behavioral and morphological characters: a literature review indicates the importance of extended maternal care.

Using literature data on reciprocal crosses, I estimated the influence of maternal effects on morphological and behavioral traits and compared these effects between mammals, birds, insects with homogametic females, and butterflies. In birds and in both groups of insects, no detectable difference between the reciprocal hybrids was observed on average, showing that in these groups, the contribution of maternal effects to the difference between the parental lines is at least rather small. In contrast to the other groups, mammals showed a significant and large influence of maternal effects on the examined characters. The large maternal effects in mammals are probably due to the extended period of parental care during gestation and lactation. It is concluded that maternal effects contributing to differences between parental lines are only widespread and important in mammals. It should be noted that these results do not show that maternal effects are absent in other animals. In the three examined groups, maternal effects may only evolve much more slowly than traits influenced by nuclear genes.

Animals↗
PubMed2004

Induction of calbindin-D9k messenger RNA and protein by maternal exposure to alkylphenols during late pregnancy in maternal and neonatal uteri of rats.

Environmental chemicals are proposed to possess hormone-like properties, such as mimicking natural hormones, inhibiting the action of hormones, and inducing abnormal gene expression. Among environmental chemicals, the alkylphenol products (APs), octylphenol (OP) and nonylphenol (NP), are derived from alkylphenol ethoxylates and have been reported to be environmentally persistent. Thus, in the present study, we examined the effect of two APs, OP and NP, on the expression of Calbindin-D(9k) (CaBP-9k) following maternal exposure during late pregnancy in maternal and fetal uteri. Treatment with a high dose (600 mg/kg body weight [BW]) of OP and NP resulted in an induction of CaBP-9k mRNA at Day 5 of lactation, as did a single treatment with diethylstilbestrol (DES) and 17beta-estradiol (E2) in maternal uteri. The expression of CaBP-9k mRNA was also induced following treatment with a high dose (600 mg/kg BW) of OP, transferred from the mother, exposed to fetuses during late pregnancy, and persisted through Day 5 of lactation. It is of interest that treatments with high doses of OP (400 and 600 mg/kg BW) reduced the expression of maternal estrogen receptor alpha (ERalpha) mRNA, as E2 did. However, all doses of NP resulted in an inhibition of neonatal ERalpha, while only the high does of OP (600 mg/kg BW) induced the reduction of neonatal ERalpha mRNA expression, as E2 did. Parallel to mRNA, the expression of CaBP-9k protein was significantly induced by treatment with a high dose of OP and NP. In conclusion, maternal exposure to APs, OP and NP, during late pregnancy increased the expressions of CaBP-9k mRNA and protein in maternal and neonatal uteri. These results suggest that the absorption and distribution of environmental estrogenic compounds in maternal and neonatal uteri are extremely rapid, and these chemicals can easily pass though the placenta during pregnancy to affect functions of neonatal reproductive tissues.

Animals↗
PubMed1994

Effect of Salmonella endotoxin administered to the pregnant sheep at 133-142 days gestation on fetal oxygenation, maternal and fetal adrenocorticotropic hormone and cortisol, and maternal plasma tumor necrosis factor alpha concentrations.

We studied the effects of maternal exposure to endotoxin on pregnancy outcome, stimulation of the hypothalamo-hypophyseal-adrenal axes (HHAA) of ewes and their fetuses, and maternal production of tumor necrosis factor alpha (TNF alpha), a central mediator in the pathogenesis of bacterial endotoxemia. Either endotoxin (lipopolysaccharide, LPS) from Salmonella typhimurium or saline was administered to pregnant sheep (n = 10) at 137.6 +/- 3.5 days gestational age by slow i.v. infusion at 1 microgram.kg-1 total dose over a 3-h period. Fetuses of ewes treated with LPS became hypoxemic by 2.5 h after initiation of LPS infusion. Maternal ACTH increased and peaked during LPS administration to levels approximately 10-fold greater in treated than in control ewes. In contrast, fetal ACTH levels were maximum at 6-12 h. Maternal and fetal cortisol levels were significantly different from control levels by 1 and 12 h, respectively. Maternal plasma TNF alpha peaked (6-7-fold over baseline) at 1-2 h after initiation of LPS administration and steadily declined over the following 48 h. Four of 5 treated ewes either delivered or their fetuses died within 28 h. In summary, infusion of LPS caused fetal hypoxemia and stimulated both fetal and maternal HHAA followed by preterm labor by 28 h after infusion in 4 of 5 ewes. Three of the fetuses died in utero. Maternal plasma TNF alpha rose rapidly, but the specific role it may play in initiation of preterm labor remains to be elucidated.

Adrenocorticotropic Hormone↗
PubMed2004

Does maternal immunoglobulin E decrease with increasing order of live offspring? Investigation into maternal immune tolerance.

BACKGROUND: Identifying the protective effect of a higher number of siblings is a significant finding in understanding the aetiology of allergic sensitization, asthma, eczema, and hayfever. Knowledge about causes behind the sibling effect may allow us to prevent atopic manifestations. OBJECTIVE: We tested the hypothesis that rising order of live offspring increases maternal immune tolerance (immune non-reactivity) against allergens. To this end, we investigated whether maternal IgE levels are associated with the number of live offspring. METHODS: In a cohort of 1456 newborns recruited between January 1989 and February 1990 on the Isle of Wight, UK, we determined maternal and cord serum IgE, and the order of live offspring. The data were analysed by means of linear and path analysis. RESULTS: Maternal and cord serum IgE were available in 820 mother-infant pairs with birth order information. We found that the number of live offspring significantly reduces maternal IgE. The decline was more prominent in mothers with atopy (n=268). The geometric means of IgE after the first, second, and third or higher delivery were 74.4, 66.6, and 43.0 kU/L, respectively. Findings of path analysis suggest a significant direct effect of birth order on maternal IgE, but no direct effect of birth order on cord serum IgE. CONCLUSION: The findings support that maternal immune tolerance against allergens may increase with increasing order of live offspring and thus pass on a lower risk of developing atopy in children of higher birth order.

Adult↗
PubMed1992

Maternal serum screening for Down's syndrome: the effect of routine ultrasound scan determination of gestational age and adjustment for maternal weight.

OBJECTIVE: To investigate the effect of using a routine ultrasound estimate of gestational age and maternal weight adjustment on maternal serum alpha-fetoprotein (AFP), unconjugated oestriol (uE3) and human chorionic gonadotrophin (hCG) levels in antenatal screening for Down's syndrome. DESIGN: Women with a singleton pregnancy without Down's syndrome were screened using the three serum markers and an estimate of gestational age based on 'dates' (time since first day of the last menstrual period) and one based on an ultrasound scan examination was recorded together with maternal weight. SETTING: Women attending the Homerton Hospital, Hackney, for their antenatal care between February 1989 and January 1990. SUBJECTS: 2113 women with a singleton pregnancy without Down's syndrome. RESULTS: The use of ultrasound to estimate gestational age (usually based on the biparietal diameter of the fetal skull) led to a significant reduction in the variance of each marker at a given week of pregnancy. The level of each marker was negatively associated with maternal weight, so that adjustment for weight also led to a reduction in variance. These data on gestational age and maternal weight, taken together with published data on pregnancies associated with Down's syndrome, indicate that the routine use of ultrasound to estimate gestational age will increase the detection rate from 58% to 67% while maintaining the false-positive rate at 5%, or reduce the false-positive rate from 5.7% to 3.1% while maintaining the detection rate at 60%. Routine maternal weight adjustment for the serum marker levels was much less useful, increasing the detection rate by about 0.5% for a given false-positive rate, or reducing the false-positive rate about 0.1% for a given detection rate. CONCLUSION: An ultrasound gestational age estimate available at the time of Down's syndrome screening confers a substantial advantage to screening performance with a further small benefit resulting from maternal weight adjustment, which is worth adopting if it can be done without difficulty or extra cost.

Biomarkers↗
PubMed1994

The association of maternal social class with maternal diet and the dimensions of babies in a population of London women.

Records of the diets of 513 London mothers towards the end of the first trimester of pregnancy have been reported previously to show the maternal nutritional intakes associated with birthweight in the optimum range, which may be assumed to approximate to basic maternal needs for reproduction. The diets associated with low birthweight and small head size were also recorded and were found to be inferior. The present paper shows social class gradients for baby size and 35 essential dietary components, providing an indication of which basic maternal nutritional needs were not always met. There was no social class gradient for intake of total energy, or the energy carriers carbohydrate and fat. There were, however, statistically highly significant social class gradients for intake of protein, seven minerals and six B-vitamins, all of which were also highly significantly correlated with birthweight. Maternal intake of these 14 components of diet fell progressively as birthweight fell, but only for the mothers of smaller babies below 3270g, the median for the study. Further increase of maternal intakes of any nutrient by mothers whose babies were above median did not apparently further increase birthweight. The social and medical problem presented by maternal nutrition is that of a minority of women who enter pregnancy with qualitatively inadequate nutritional status. This minority is found in all social classes but increases from social class I to V, and further still among single mothers. The women comprising this minority eat foods not meeting basic maternal needs for a range of nutrients characteristic of whole grains, vegetables and fruit and dairy produce, which may partly be explained by their high cost.

Alcohol Drinking↗
PubMed2001

Relationships between placental GH concentration and maternal smoking, newborn gender, and maternal leptin: possible implications for birth weight.

The control of fetal growth depends on multiple hormones, including both IGF-I and placental GH (PGH) in the mother, and IGF-I rather than pituitary GH (pitGH) in the fetus. Leptin, which is produced by adipocytes and syncitiotrophoblast cells, has also been thought to influence fetal growth by an as yet unknown mechanism. This study assessed the relationships between the GH-IGF-I axis in mothers and newborns, and maternal smoking, neonate gender, and maternal and fetal leptin. We collected blood in 87 mothers at the onset of labor and cord blood immediately after birth in their 87 healthy full-term newborns. GH concentrations were log(10) transformed, and data were expressed as the geometric mean (-1, +1 tolerance factor). PGH was lower in the 30 smoking mothers, as compared with the 57 nonsmoking mothers [18.2 (11.5; 28.6) vs. 27.0 (15.1; 48.2) microg/liter, P < 0.01]. Cord blood IGF-I was lower in neonates from smoking mothers (90 +/- 44 vs. 135 +/- 65 microg/liter, mean +/- SD, P < 0.01), consistent with their lower birth weight percentile (P < 0.01). A gender effect was observed for PGH, which was higher when the newborn was female, and for newborn pitGH and newborn leptin, which were, respectively, lower and higher in females, even after adjustment for birth weight and maternal smoking category (P < 0.05 for all comparisons). Multiple regression analyses identified maternal leptin as a negative predictor of PGH (P < 0.05) and newborn leptin as a positive predictor of newborn IGF-I (P < 0.05). Maternal smoking is associated to decreased maternal PGH and cord blood IGF-I concentrations. A sexual dimorphism for PGH, newborn pitGH, and newborn leptin exists at the time of birth, but its physiological significance remains to be studied. The relationships between maternal leptin and PGH and between cord blood leptin and IGF-I are consistent with the hypothesis that leptin could contribute to the control of fetal growth.

Birth Weight↗
PubMedDate not supplied

[Birth weight and maternal characteristics at the Maternity of Campinas along 25 years]

OBJECTIVE: To study the secular trends of birthweight and maternal characteristics at the Maternity of Campinas, São Paulo, Brazil, from 1971 to 1995. METHODS: The authors studied 18,262 newborns in the Maternity of Campinas. Birthweight and maternal characteristics were analyzed comparing changes occurred every 5 years. The data were analyzed by chi-square test, analysis of variance, multivariate logistic regression, and population attributable risk. RESULTS: The results showed a positive trend for birthweight only in the period between 1976 and 1980 (P<0.05). The frequency of low birthweight was constant, remaining around 8.0%, but towards the end of the studied period, it started to be predominantly seen among preterm newborns. The frequency of favorable weight was below 70.0%. The authors observed an increase in the number of pregnant adolescents, pregnant women working outside home, unmarried mothers, cesarean sections, frequency of preterms, and decrease of parity (P<0.05). The maternal characteristics associated with low birthweight were: unmarried status, maternal age of 17 years old or less, maternal age of 35 years or more, public medical-hospital assistance, nonwhite skin color, primiparity, multiparity, and female newborns. In the 90s, 44.3% of low birthweight was attributed to preterm newborns. CONCLUSIONS: Even with a positive development of the general conditions considered important to improve population s health, birthweight has not increased, probably as a reflex of other changes that held back this advance.

Journal Article↗
PubMed1986

Maternal suprachiasmatic nuclei are necessary for maternal coordination of the developing circadian system.

During late fetal and early neonatal life, the maternal circadian system coordinates the timing of a circadian clock in the hypothalamic suprachiasmatic nuclei (SCN) to the prevailing light-dark cycle. The role of the maternal SCN in the process of maternal coordination was investigated in rats. Complete lesions of the maternal SCN on day 7 of gestation disrupted rhythms of SCN glucose utilization in fetuses and pineal N-acetyltransferase activity in 10-d-old pups. This disruption was probably due to the desynchronization of individually oscillating fetal SCN, because individual pups born to and reared by SCN-lesioned dams under constant conditions exhibited normal circadian rhythms in drinking behavior. Cross-foster studies showed that the maternal circadian system can coordinate developing circadian rhythmicity during either the pre- or postnatal period. The results indicate that the maternal SCN are a necessary component of the mechanism of maternal coordination during both the pre- and postnatal periods.

Acetyltransferases↗