Narrow intra-individual variation of maternal thyroid function in pregnancy based on a longitudinal study on 132 women.

Background: Adaptive alterations in maternal physiology cause changes in thyroid hormone levels throughout pregnancy, and precise biochemical evaluation is thus highly dependent on gestation-specific reference intervals and expected intra-individual variation.

Objective: The aim of the study was the assessment of the intra-individual variation as well as the longitudinal course of thyroid hormones during normal pregnancy and factors that influence the normal reference range for thyroid function. For this purpose, a longitudinal statistical model was applied.

Acquired cryptorchidism is frequent in infancy and childhood.

Accurate prevalence data for acquired cryptorchidism are currently sparse and systematic prospective studies have not yet been reported. Our aim was to determine the prevalence of testicular ascent in childhood. In a prospective longitudinal population-based child cohort from Copenhagen, Denmark (1997-2007), testicular position was examined according to a standardised protocol in a total of 1072 boys, at birth (n = 1051), at 3 months (n = 983), 18 months (n = 888), 36 months (n = 790) and again once between 4 1/2 and 10 years of age (n = 509).

From mother to child: investigation of prenatal and postnatal exposure to persistent bioaccumulating toxicants using breast milk and placenta biomonitoring.

The exposure levels of placenta and paired breast milk samples to selected organochlorine compounds and pesticides from Danish and Finnish samples have been investigated. p,p'-DDE is the dominant pollutant, beta-HCH, hexachlorobenzene, endosulfan-I, dieldrin, oxychlordane, cis-heptachlor epoxide and p,p'-DDT being the other major constituents. Their concentrations are linearly correlated between milk and placenta in similar patterns for Danish and Finnish samples.

Serum insulin-like growth factor-I (IGF-I) and growth in children born after assisted reproduction.

Context: Concern has been raised about the safety of assisted reproduction techniques for the offspring.

Objectives: The objective of the study was to investigate postnatal growth and growth factors in children born after intra-cytoplasmatic sperm injection (ICSI) and in vitro fertilization (IVF).

Design: The study had two cohorts: a population-based longitudinal infant cohort 0-36 months [236 ICSI, 173 IVF, 1530 naturally conceived (NC)], and a cross-sectional child cohort at 5 yr (68 ICSI, 67 IVF, 70 NC).

Larger testes and higher inhibin B levels in Finnish than in Danish newborn boys.

Context: Recent studies showed that male reproductive health problems, such as cryptorchidism, hypospadias, testicular cancer, and low sperm quality, are more prevalent in Denmark than in Finland.

Objectives: We hypothesized that, if fetal testicular dysgenesis contributed to these observations, differences in gonadal development and the hypothalamus-pituitary-testis axis would already be detectable perinatally. Thus, we investigated healthy newborn boys in both countries.

Human breast milk contamination with phthalates and alterations of endogenous reproductive hormones in infants three months of age.

Unlabelled: Phthalates adversely affect the male reproductive system in animals. We investigated whether phthalate monoester contamination of human breast milk had any influence on the postnatal surge of reproductive hormones in newborn boys as a sign of testicular dysgenesis.

Design: We obtained biologic samples from a prospective Danish-Finnish cohort study on cryptorchidism from 1997 to 2001.

Hormonal changes in 3-month-old cryptorchid boys.

Context: Hormonal dysregulation has been suggested to be one of many etiological factors of cryptorchidism.

Objectives: The objective of this study was to assess the hypothalamic-pituitary-testicular axis in cryptorchid boys during the postnatal hormonal surge.

Design: This was a prospective, longitudinal, population-based study.

Postnatal penile length and growth rate correlate to serum testosterone levels: a longitudinal study of 1962 normal boys.

Objective: Infant boys show a brief activation of their hypothalamic-pituitary-gonadal axis shortly after birth, the physiological significance of which is poorly understood. The objective of the study was to investigate the correlation between endogenous testosterone levels and penile size and growth.

Design: Prospective, longitudinal population-based study taking place at two large primary obstetric centres at the University Hospitals of Copenhagen, Denmark, and Turku, Finland.

Kidney growth in 717 healthy children aged 0-18 months: a longitudinal cohort study.

Kidney size is an important parameter in the evaluation of children with renal disease. However, reference materials for kidney size in healthy children have been limited beyond the neonatal period. We performed a longitudinal cohort study of 717 healthy children born at term with normal birth weight.

Intrauterine growth retardation and consequences for endocrine and cardiovascular diseases in adult life: does insulin-like growth factor-I play a role?

Low birth weight has been associated with an increased incidence of ischaemic heart disease (IHD) and type 2 diabetes. Endocrine regulation of fetal growth by growth hormone (GH) and insulin-like growth factor (IGF)-I is complex. Placental GH is detectable in maternal serum from the 8th to the 12th gestational week, and rises gradually during pregnancy where it replaces pituitary GH in the maternal circulation.

Increase in maternal placental growth hormone during pregnancy and disappearance during parturition in normal and growth hormone-deficient pregnancies.

Objective: The purpose of this study was to evaluate placental growth hormone levels in maternal circulation throughout pregnancy in normal and growth hormone-deficient women with the use of a specific assay and to determine the clearance of placental growth hormone from maternal circulation after birth.

Study Design: Seventeen healthy pregnant women and 1 patient with growth hormone deficiency substituted with recombinant growth hormone during pregnancy participated in a longitudinal study from early pregnancy until birth with repetitive blood sampling and measurement of placental growth hormone levels throughout pregnancy. Furthermore, serial blood samples were drawn before, during, and after elective caesarean deliveries in 5 healthy women to calculate the half-life of placental growth hormone.

Gender difference in breast tissue size in infancy: correlation with serum estradiol.

Breast tissue in newborn infants is considered to be physiologic and mainly related to exposure to maternal hormones in utero or through breast-feeding. However, controversy exists as to whether breast tissue in later infancy is under the influence of endogenous hormones. Children at 2-4 mo of age have a surge of reproductive hormones, including estradiol, which may affect the mammary gland.

Longitudinal study of serum placental GH in 455 normal pregnancies: correlation to gestational age, fetal gender, and weight.

Placental GH is thought to be responsible for the rise in maternal IGF-I during pregnancy and is considered to be important for fetal growth. In this prospective longitudinal study of healthy pregnant women, we investigated determinants of placental GH in maternal serum. Serum was obtained from 455 women with normal singleton pregnancies at approximately 19 and 28 wk gestation.