The transition from fetus to neonate--an endocrine perspective

The transition from fetus to neonate involves three phases: late gestation, parturition and the processes needed to establish independent homoeostatic regulation after separation from the placenta. These phases are regulated by a series of fetal and placental endocrine events. Glucocorticoids have an important role in the preparation for birth, including involvement in lung and cardiac development, and the maturation of enzymes in a variety of pathways. Fetal cortisol production is, in turn, also under hormonal control. Parturition is a complex process, which is still poorly understood in humans. The final steps are largely dependent on the effect of prostaglandin F2 alpha on the myometrium associated with increased oxytocin activity. The transition to birth is accompanied by changes in respiration, circulation, glucose homoeostasis, and the onset of independent oral feeding and thermoregulation. Several examples of endocrine components of the transition from fetal to neonatal life are reviewed here: the role of prostanoids, the onset of thermogenesis, and changes in the thyroid hormone and growth hormone axes. The effects of hormone levels on prematurity and growth retardation are also discussed.     

Endocrinology in preadolescents and adolescents. I. Hormonal changes during normal puberty.

Hormonal changes during puberty have been well described: rise of gonadotropins followed by the rise of gonadal secretions at ages 10 to 16 years. The most striking new data are in fact concerning events that occur before puberty, first during the first months of life, second at age 7 years. The first event consists of a rise of gonadal steroids, which gives a hormonal impring that might be important for the future of the child. The second event concerns the prepubertal maturation of the androgenic zone of the adrenal cortex and the increasing secretion with age of the adrenal androgens. The mechanism of onset of both events is poorly explained. What causes the rise of gonadal steroids during infancy is unknown. Which pituitary factor, in addition to ACTH, stimulates the corticoadrenal androgenic zone, and which mechanism regulates its secretion remain unknown.     

Amniotic fluid and plasma concentrations of pregnancy-associated plasma protein-A (PAPP-A) throughout pregnancy: comparison with other fetoplacental products

The development of a sensitive radioimmunoassay has enabled measurements of pregnancy-associated plasma protein-A (PAPP-A) to be performed from early pregnancy. The present paper compares the plasma concentrations of PAPP-A with the levels of two trophoblastic proteins, human placental lactogen (hPL) and the beta-subunit of human chorionic gonadotrophin (beta-hCG), with a steroid of fetoplacental origin, total oestriol (total E3), and with a fetal protein, alpha-fetoprotein (AFP). PAPP-A was also measured in amniotic fluid and in maternal urine. In contrast with the secretion of the other substances studied, which either reach a plateau or even decrease during the last 4 weeks of pregnancy, PAPP-A steadily increased in the maternal circulation from 7 to 40 weeks gestation. It is proposed that PAPP-A production is either not related to placental mass or that PAPP-A is not of trophoblastic origin. The increase of PAPP-A in amniotic fluids parallels the increase in maternal blood; virtually no PAPP-A is excreted in urine.     

Bronchial artery embolization: monitoring with somatosensory evoked potentials. Work in progress

Surgery remains the treatment of choice for massive and recurrent hemoptysis. In some instances, however, immediate surgical intervention is contraindicated. In these situations, bronchial artery embolization (BAE) has proved to be a successful definitive treatment for non-surgical candidates and a palliative therapy in patients requiring hemodynamic stabilization prior to surgery. The most serious complication of BAE is spinal cord ischemia. This relates directly to the potential anastomotic connections between the bronchial circulation and the anterior spinal artery. Somatosensory evoked potentials (SSEPs) have been used in the past to monitor spinal cord ischemia during procedures that threaten the vascularity of the spinal cord. The authors report two cases in which SSEPs were employed to monitor spinal cord ischemia during bronchial artery embolization.     

Effect of Community-based Behavior Change Communication on Delivery and Newborn Health Care Practices in a Resettlement Colony of Delhi

Background:

Neonatal morbidity and mortality in India continue to be high. Among other reasons, newborn care practices are major contributors for such high rates.

Objective:

To assess the effect of behavior change communication (BCC) package among pregnant women regarding neonatal care.

Materials and Methods:

Semistructured and pretested schedule was used to interview 200 multigravidas on various aspects of neonatal care. Based on the preliminary data, BCC package was designed and implemented in intervention block in the community. Follow-up was done to find out change in their behavior.

Statistical Analysis:

Data were analyzed using Epi info and Fischer exact test and chi-square test were applied in the baseline data. A P value of less than 0.05 was considered significant. Effect of the BCC package is given in terms of relative risk.

Results:

BCC package increased 1.76 times higher number of deliveries conducted by trained dais in intervention group. There was significant improvement in using sterile cord tie (P = 0.01), applied nothing to the cord (P < 0.0001) and giving bath to their baby within 6 h of birth (P = 0.02) in intervention group as compared to nonintervention group. Significant difference was found between the two groups with regard to breastfeeding practices of baby. Harmful practices were reduced in the intervention group. Significant improvement was found in intervention group as compared to nonintervention group with regard to knowledge of danger signals, physiological variants, management of breastfeeding-related problems, and awareness of skin-to-skin technique for the management of hypothermic baby.

Conclusion:

Inadequate knowledge and adverse practices regarding neonatal care among mothers in study areas were found. BCC package had favorable impact on behavior of mothers for neonatal care in intervention group.     

Response from lieberman and colleagues

Respond on comments on Lieberman's article: Cyclosiloxanes Produce Fatal Liver and Lung Damage in Mice. Environ Health Perspect 107:161-165     

Normal sexual maturation

Puberty represents a period of important changes which lead to sexual maturation and active functions of reproduction. Sequences of the somatic and hormonal changes are presented both in boys and girls. Mean ages of onset of puberty are 10.9 and 11.2 in girls and boys, respectively. Menarche occurs at a mean age of 13.4 years and may be related to a critical weight. In boys, testicular growth above 4 cm2 or 4 ml is the first clinical sign of gonadal pubertal maturation. In girls, the first sign is the budding of the breast. At onset of puberty, the hypothalamus resumes a marked pulsatile secretion of gonadotropin-releasing hormone, leading to an increased secretion of pituitary gonadotropins which in turn stimulate the gonadal functions, i.e. the secretion of testosterone or estradiol and maturation of the spermatogenesis or the ovarian follicle. Neuroendocrine factors which probably control the onset of puberty are numerous: adrenergic or dopamine neurotransmitters, endogenous opioids, melatonin from the pineal gland. Gonadal maturation (gonadarche) is preceded in the infant by a postnatal surge of luteinizing hormone and at age 7-8 years by an adrenal maturation called adrenarche.