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PubMed1981

Social and sensory environment of low birth weight infants in a special care nursery. An anthropological investigation.

Ten infants of 900 to 1500 gram birthweight and 28 to 32 weeks gestational age were observed for a total of 552 hours in an intensive care nursery. Auditory environment and tactile experience were recorded by tape recorder and observers' notes for a period of 24 consecutive hours at weekly intervals in each of the first 3 weeks of life. Besides regular recording of heart rate and motor activity, episodic events were also noted such as interaction with staff or parents, or periods of apnea. Results are primarily descriptive of this environment, denoting sound level of ground noise, kinds of sounds that penetrate the isolette, responses of the infants to these sounds, differences in auditory environment with different caretakers, and motor activity as related to auditory and tactile events. In response to questions of the usefulness of sensory stimulation programs for preterm infants, these descriptive results suggest some of the deficiencies and complexities of this life experience at this gestational age, and suggest some areas for further research as well as for clinical management of premature infants.

Female↗

PubMed2003

Use of alpha-blockers and the risk of hip/femur fractures.

OBJECTIVE: To study the association between use of alpha-blockers and risk of hip/femur fractures. DESIGN: Population-based case-control study. SETTING: General Practice Research Database. SUBJECTS: Cases were defined as men, aged 40 years and older with a first diagnosis for hip/femur fracture. Controls were matched 1 : 1 on gender, year of birth and general practitioner-practice. RESULTS: In all, 4571 cases and an equal number of controls were identified. Current use of alpha-blockers (prazosin, doxazosin, indoramin, terazosin, alfuzosin and tamsulosin) was compared with non-use of alpha-blockers. Current use of alpha-blockers on the index date was associated with an increased risk of hip/femur fracture [adjusted odds ratio (OR) 1.9, 95% confidence interval (CI): 1.1-3.0] in the overall analysis. The effect was particularly strong for first prescriptions within a treatment episode (adjusted OR 5.1, 95% CI: 1.0-31.7) and during the first month of treatment (adjusted OR 4.1, 95% CI: 0.7-23.9). Stratification according to indication of use showed that current use of alpha-blockers was not associated with hip/femur fracture in men with a diagnosis of benign prostatic hyperplasia (adjusted OR 1.0, 95% CI: 0.4-2.5), but was associated in men who used alpha-blockers for cardiovascular disease (adjusted OR 2.8, 95% CI: 1.4-5.4). CONCLUSION: Current use of alpha-blockers was associated with an increased risk of hip/femur fracture and with the start of a new treatment episode. The effect seemed to be confined to patients who used alpha-blockers for cardiovascular disease. Caution with respect to first-dose effects related to the initiation of a new episode of alpha-blocker treatment is advised.

Adrenergic alpha-Antagonists↗

PubMed1999

Trends in cervical intra-epithelial neoplasia in Iceland through 1995: evaluation of targeted age groups and screening intervals.

BACKGROUND: Targeted age groups and screening intervals are dependent on the age-specific prevalence of the preclinical disease and the length of the detectable pre-clinical phase. This study evaluates the UICC and EC recommendations regarding targeted age group and screening intervals based on the Icelandic screening experience. METHODS: The trends for cytologic preinvasive lesions were analyzed at first visit during the period 1966-1995, at second and later visits after a normal test(s) taken after 1985, and finally at any visit in 1991-1995. The frequency of histologic lesions was calculated for the birth cohort from the age of 60 and among women referred for colposcopic examination in 1994. RESULTS: The prevalence of preinvasive disease has increased significantly since 1980, and the rate of moderate to high-grade cytologic and histologic lesions begins increasing as early as 20 years of age. The rate of these lesions starts to accumulate at 24 to 36 months after a normal smear, but the rate decreases with the number of negative smears taken. Among correctly screened women the rate of histologically verified moderate to high-grade lesions and invasive disease is practically non-existent after the age of 60, while among the younger women cases with microinvasive disease start to appear within 2 to 3 years after a normal smear. CONCLUSION: Screening should start soon after age 20 with a screening interval of 2 to 3 years. The screening interval can probably be extended to 4 years at the age of 50 and stop at the age of 60 to 64 among regularly screened women.

Adult↗

PubMed1990

Weight gain during pregnancy in adolescence: predictive ability of early weight gain.

Pregnancy weight gains were examined at 4-week intervals from 12-36 weeks' gestation and total gain assessed at delivery in a cohort of 2008 pregnant women aged 18 or less at entry to prenatal care. As early as 12 weeks' gestation, there was a significant association between the amount of weight gained and infant birth weight measured at the time of delivery. At 16 weeks' gestation, gains below the 25th percentile were associated with an increased risk of low birth weight (LBW) (adjusted odds ratio 1.56; 95% confidence interval 1.01-2.43), and by 20 weeks' gestation, the risk of LBW was doubled (adjusted odds ratio 2.00; 95% confidence interval 1.34-2.99). Also at 16 weeks, there was a doubling in the risk of excessive fetal size or macrosomia (adjusted odds ratio 2.31; 95% confidence interval 1.31-4.10) associated with maternal weight gain above the 75th percentile. These results suggest that an increased risk of certain poor pregnancy outcomes is detectable late in the first or early in the second trimester. Consequently, weight gain monitoring may be important early in pregnancy.

Adolescent↗

PubMed1997

Age when maximum height is reached as a risk factor for breast cancer among young U.S. women.

We evaluated height as a potential risk factor for breast cancer in a case-control study of 747 young women diagnosed with invasive breast cancer before age 46 years and 961 control subjects recruited by random digit dialing. We found that total height attained did not affect a woman's risk of the disease. The age when a women reached her maximum height, however, was a risk factor for breast cancer. There was a trend of decreasing risk of breast cancer in relation to increasing age of height attainment, culminating in a 30% reduction in the risk of breast cancer for women who reached their maximum height when they were 18 years or older compared with women who reached their maximum height when they were 13 years old or less (odds ratio = 0.7; 95% confidence interval = 0.5-1.0). Although the age at menarche was correlated with the age at maximum height, the effect of age at maximum height persisted after adjustment for age at menarche. Previous studies have reported that age at menarche is an important determinant of risk, but this study indicates that age when maximum height is reached may be another, and possibly more important, landmark of puberty that is related to breast cancer risk. The physiologic basis for this claim may lie in the influence on breast development of exposure to growth hormone and insulin-like growth factor during puberty, and on a decreased time between the end of puberty and a woman's first livebirth, both of which are believed to affect a woman's risk of breast cancer.

Adolescent↗

PubMedDate not supplied

Breastfeeding among patients with congenital malformations.

BACKGROUND: This study was undertaken in order to 1) determine the frequency of infants with major congenital malformations who are breastfed and 2) identify factors associated with initiating and early weaning of breastfeeding. METHODS: We conducted a descriptive cohort study at a tertiary-care pediatric hospital. Subjects included infants <20 days of age with major congenital malformations. According to the feeding pattern, the following three groups were identified: exclusively breastfed (EB); alternating breast and formula (ABF), and exclusively formula (EF).Follow-up interviews were conducted on a monthly basis until the infants were 6 months of age. The feeding pattern was determined during each visit. Reasons for changing the breastfeeding pattern were explored. RESULTS: A total of 120 newborns were recruited. At the time of the first interview, 29.2% were EF, 47.5% EB, and 23.3% ABF. By 6 months of age, the feeding patterns were 8.6, 18.1, and 73.3%, respectively. Median length of breastfeeding was 3 months (range: 1-6 months). The maternal prenatal decision to breastfeed (odds ratio [OR] 0.11, 95% confidence interval [95% CI] 0.02-0.52) and attendance at prenatal breastfeeding sessions (OR 0.30, 95% CI 0.17-0.87) were associated with breastfeeding initiation. Conversely, mother-child separation (OR 3.07, 95% CI 1.36-7.01) and low birth weight (OR 2.98, 95% CI 1.36-6.48) were associated with a lack of breastfeeding. The mother's sensation of low milk production was the main reason to change or to stop breastfeeding. CONCLUSIONS: In this study, breastfeeding frequency and length among infants with congenital malformations during the first 6 months of life were lower than previously published reports of breastfeeding obtained from healthy infants. Healthcare professionals must encourage breastfeeding in these infants.

Breast Feeding↗

PubMed2001

The first signs of beta-cell autoimmunity appear in infancy in genetically susceptible children from the general population: the Finnish Type 1 Diabetes Prediction and Prevention Study.

Little is known about the timing of the etiological events and the preclinical process of type 1 diabetes during the first years of life in the general population. In this population-based prospective birth cohort study, the appearance of diabetes-associated autoantibodies as a sign of beta-cell autoimmunity and the development of type 1 diabetes were monitored from birth. Of 25,983 newborn infants, 2,448 genetically susceptible children were monitored for islet cell antibodies (ICA) at 3- to 6-month intervals. If an infant seroconverted to ICA positivity, all his/her samples were also analyzed for insulin autoantibodies (IAA), antibodies to the 65-kDa isoform of glutamic acid decarboxylase, and antibodies to the protein tyrosine phosphatase-related IA-2 molecule. Fifteen children of those who carried the high-risk genotype (2.7%) and 23 of those who carried the moderate-risk genotype (1.2%; P = 0.019) tested positive for ICA at least once. Among those who showed positivity for at least 2 antibodies during the observation period (25 of 38), IAA appeared as the first or among the first antibodies in 22 children (88%) and emerged earlier than the other antibodies (P < 0.019 or less). The first autoantibodies appeared in the majority of the children in the fall and winter (30 of 38 vs. 8 of 38 in the spring and summer, P < 0.001). These observations suggest that young children in the general population with a strong human-leukocyte-antigen-DQ-defined genetic risk of type 1 diabetes show signs of beta-cell autoimmunity proportionally more often than those with a moderate genetic risk. IAA emerge as the first detectable antibody more commonly than any other antibody specificity, implying that insulin may be the primary antigen in most cases of human type 1 diabetes associated with the DR4-DQB1*0302 haplotype. The seasonal variation in the emergence of the first signs of beta-cell autoimmunity suggests that infectious agents may play a role in the induction of such autoimmunity.

Autoantibodies↗

PubMed1996

Abortion and breast cancer risk.

The relationship between spontaneous and induced abortions and breast cancer risk was analyzed using data from a case-control study conducted between June 1991 and February 1994 in 6 Italian centers on 2,569 histologically confirmed incident breast cancer cases and 2,588 controls admitted to hospital for a wide range of acute, non-neoplastic, non-hormone-related diseases. One or more abortions were reported by 31% of cases and 32% of controls, corresponding to a multivariate odds ratio (OR) of 1.0 (95% confidence interval [CI], 0.8-1.1). No trend in risk was observed with increasing number of total abortions or spontaneous and induced abortions separately. No significant relationship was found between the risk of breast cancer and history of spontaneous or induced or total abortions in separate strata of age at diagnosis, number of children, time of abortion in relation to first birth and family history of breast cancer. When abortion was the outcome of the first pregnancy, the OR was 1.2 for spontaneous and 1.3 for induced abortion, in relation to women with birth as outcome of the first pregnancy, and 1.0 and 1.1, respectively, when the reference category was nulligravidae. Thus, our results indicate a lack of association between induced and spontaneous abortions and breast cancer risk.

Abortion, Induced↗

PubMed2003

[Dating biometry with crown-rump length, precision of a routine practice].

OBJECTIVE: The goal of this study was to determine the accuracy of an everyday practice for assessing gestational age by ultrasound and redefine the correction of gestational age policy. MATERIALS AND METHODS: This study used first trimester measurements taken during a three-year period. We considered all births from pregnancies that began by an in vitro fertilization procedure. We examined 143 consecutive files containing 257 measurements made by 72 different operators. We applied two reference curves to calculate the date the pregnancy began and the centiles of the prediction interval for +/- 7, +/- 5 and +/- 3 days. RESULTS: The prediction intervals for +/-7, +/-5, +/-3 days excluded 2%, 6%, and 25% respectively of the embryos from one of the two reference curves. These intervals were 1%, 5% and 20%, were better for the other curve. CONCLUSION: Correction of gestational age has to take into consideration variations in the embryo length. We correct the gestational age only if the difference with ultrasound assessment is more than one week.

Adult↗

PubMed1991

Birth order and breast cancer risk.

It has been hypothesized that prenatal exposure to maternal estrogens may be a risk factor for breast cancer in the offspring. In two recent studies, maternal estradiol levels in the first pregnancy have been compared to those in the second, and in both studies levels were higher in the first pregnancy. If both the hypothesis and the reported findings were true, women born as their mother's second child would be expected to have lower risk for breast cancer than first-born women. Data from 1,468 cases of breast cancer and 4,175 hospital controls from three previously published studies were modelled through multiple logistic regression to evaluate this possibility. The size of the woman's sibship was not related to breast cancer risk. On the other hand, second-born women had, as predicted, lower breast cancer risk than first-born women, although the difference was nominally significant only among premenopausal women. The relative risk for breast cancer, contrasting second-born to first-born women, and the corresponding 95 per cent confidence intervals, were 0.71 (0.54-0.94) among premenopausal women, 0.94 (0.76-1.17) among postmenopausal women, and 0.86 (0.73-1.02) among all women, controlling for menopausal status.

Birth Order↗

PubMed2006

New parents and mental disorders: a population-based register study.

CONTEXT: Studies on postpartum mental disorders among mothers have primarily focused on either depression or psychoses and have generally not included the broader spectrum of mental disorders. A few studies have found that some men have symptoms of depression after becoming fathers, but these studies have not documented whether this exceeds the morbidity among men in general. OBJECTIVES: To estimate the risk of postpartum mental disorders necessitating hospital admission or outpatient contact for mothers as well as fathers during a 1-year postnatal follow-up period after birth of first live-born child and to investigate whether parents in general differ from nonparents in the risk of admission with a mental disorder and how this difference varies with age. DESIGN, SETTING, AND PATIENTS: Register-based cohort formed by linking information from Danish health and civil service registers. A total of 2,357,942 Danish-born persons were followed up from their 15th birthday or January 1, 1973, whichever came later, until date of onset of the disorder in question, date of death, date of emigration from Denmark, or July 1, 2005, whichever came first. From 1973 to 2005, a total of 630,373 women and 547,431 men became parents for the first time, and during the first year after childbirth, these parents contributed 1,115,639 person-years at risk. MAIN OUTCOME MEASURE: First-time psychiatric hospital admission or outpatient contact 0 to 12 months after becoming a parent. RESULTS: A total of 1171 mothers and 658 fathers were admitted with a mental disorder to a psychiatric hospital during the first 12 months after parenthood, and the corresponding prevalence of severe mental disorders through the first 3 months after childbirth was 1.03 per 1000 births for mothers and 0.37 per 1000 births for fathers. Compared with women who had given birth 11 to 12 months prior, primiparous women had an increased risk of incident hospital admission with any mental disorder through the first 3 months after childbirth, with the highest risk 10 to 19 days postpartum (relative risk [RR], 7.31; 95% confidence interval [CI], 5.44-9.81). Among mothers, risk was also increased for psychiatric outpatient contacts through the first 3 months after childbirth, also with the highest risk occurring 10 to 19 days postpartum (RR, 2.67; 95% CI, 1.99-3.59). Unlike motherhood, fatherhood was not associated with any increased risk of hospital admission or outpatient contact. CONCLUSION: In Denmark, the risk of postpartum mental disorders among primiparous mothers is increased for several months after childbirth, but among fathers there is no excess of severe mental disorders necessitating admission or outpatient contacts.

Adult↗

PubMed2001

Two interactive genes responsible for a new inherited cataract (RCT) in the mouse.

We discovered a mutant mouse, RCT (Rinshoken cataract), with a new congenital cataract in strain SJL/J. The opacity of the lens associated with microphthalmia could be observed visually at 3 to 3.5 months of age. Marked degeneration of the lens, including loss of the fine structure of the lens fibers and swelling of epithelial cells with vacuoles of various sizes in the cortex, but no other defects except photoreceptor degeneration in the retina, was detected. Histological change in the lens was first observed at 2 days after birth. No sex-related differences were detected, and normal phenotypes in the F1 progeny of RCT and normal mice indicated that the cataract was recessive. The chromosomal location of the causative gene was determined by interval mapping by using intersubspecific backcross progeny of RCT and MSM/Ms, an inbred strain from the Japanese wild mouse Mus musculus molossinus. Backcross progeny were divided into three groups according to phenotype: mice (1) with an early-onset cataract, which can be detected visually as in RCT mice, (2) with a late-onset cataract, which can be detected histologically but not visually, and (3) with a normal lens. Three phenotypes were found to be expressed by allele combinations of two recessive genes, rct and mrct (a modifier of rct). The rct locus essential for the onset of the cataract was tightly linked to D4Mit278 on Chromosome (Chr) 4 with no recombination. The mrct locus was closely linked to D5Mit239 (chi2 = 66.3, P << 0.00001) on Chr 5.

Animals↗

PubMed2004

Natural history of multicystic kidney conservatively managed: a prospective study.

We report the long-term clinical results of conservative management of children with unilateral multicystic dysplastic kidneys (MCDK). Between 1989 and 2002, 43 children with MCDK detected by prenatal ultrasonography were prospectively followed. At birth, ultrasonography confirmed the prenatal findings in all cases. Patients underwent a radioisotope scan and micturating cystogram in order to confirm the diagnosis and to exclude other uropathies. Follow-up ultrasound (US) examinations were performed at 6-month intervals during the first 2 years of life and yearly thereafter. The mean follow-up time was 42 months (range 12-156 months). Two children developed hypertension during follow-up. In total 257 US scans were performed. The mean number of US scans per patient was 6 (range 3-10). US scans demonstrated partial involution of the MCDK in 30 (70%) cases and complete involution in 8 (19%). The absolute MCDK length remained almost unchanged in 5 children (11%). The estimated median time of complete involution of the MCDK was 122 months [95% confidence interval (CI)=86-158 months]. A total of 33 (76.7%) contralateral kidneys underwent compensatory hypertrophy, reaching a renal length above the 95th percentile during follow-up. The estimated median time for the occurrence of compensatory hypertrophy was 30 months (95% CI=15-45 months). In conclusion, the natural history of MCDK is usually benign but patients must have long-term follow-up with US scans and blood pressure measurements.

Disease Progression↗

PubMed2005

["Designer baby" changed to French for "double hope baby"].

Scientific advances during the last decades regarding potential intervention on embryos arouse many questions in society to prepare the ground concerning the limits that should be set for these practices. For the first time in 1994, a parliamentary proceeding allowed the definition of a French model of bioethics through laws of the same name. These laws, among others, authorized in a well and strictly defined setting the practice of preimplantation genetic diagnosis (PGD). Because of technical progress concerning PGD, new questions arose, especially concerning the accomplishment of designer babies. The French Chamber of Representatives came in with a new law that banishes the concept of designer babies and replaces it with another concept: double hope babies, in French "bébé du double espoir". A first hope of a pregnancy giving birth to a healthy child and the second being that this child conceived with the aid of PGD could help treat an elder brother. Because of the issuing of two specific laws in a ten years interval, France occupies a privileged place in a Europe where bioethical issues continue to be debated, particularly PGD.

Bioethics↗

PubMed2002

The effects of analgesia in the vulnerable infant during the perinatal period.

Although our knowledge of pain and its management in the perinatal period has increased, little is known about the first hours and days of life when major physiologic transition events occur. Prematurity and critical illnesses further complicate analgesic use during this time. Increased morbidity and mortality have been shown in infants receiving placebo infusions after surgery compared with infants with analgesia, highlighting the negative consequences of pain in infants. Opioids can help promote hemodynamic stability, promote respirator synchrony, and decrease the incidence of grade III & IV intraventricular hemorrhage in ventilated preterm neonates. Long-term follow-up studies suggest improved behavioral and cognitive outcomes in children given morphine infusions during NICU confinement. The necessity of fetal analgesia is dictated by the ability of the fetus to feel pain and by the adverse effects of noxious stimuli on future sensory development. Effects of drugs given to the pregnant woman on the (preterm) newborn might be influenced by decreased or absent transplacental transport, compression of the umbilical cord during delivery, or diminished blood flow in the placenta in pre-eclamptic women, resulting in higher serum concentrations. Pharmacokinetics and drug metabolism change in the last trimester, and pain sensitivity may be altered after 32 weeks of gestation. Consequently, dose and dose interval may vary considerably between neonates and within an individual during the first days of life. This subpopulation is not homogenous, and drug doses in a term neonate with a postnatal age of 2 weeks may be quite different from those at birth and are certainly different from those in a premature neonate. Size must be disentangled from age-related factors when examining developmental pharmacokinetic parameters. There are no longitudinal studies published investigating the pharmacokinetic properties of any analgesic more than once per infant. Polymorphisms of the genes encoding for the enzymes involved in the metabolism of analgesics or in genes involved in receptor expression may contribute to the large interindividual pharmacokinetic parameter variability. Polymorphism of the human mu opioid receptor has not yet satisfactorily explained pharmacodynamic variability.

Analgesia↗

PubMed2002

Comparison of perinatal health of children born from IVF in Finland in the early and late 1990s.

BACKGROUND: The purpose of this study was to investigate whether perinatal health outcomes changed during the 1990s with the increasing use of IVF. METHODS: Data were from the Finnish Medical Birth Register for periods 1991-1993 and 1998-1999. Outcomes of IVF infants and other infants were compared, both overall and separately for singleton and multiple births, by adjusting for mothers' background variables by logistic regression. RESULTS: The IVF multiple birth rate, especially the number of triplets, declined from the first (1991-1993) to the second (1998-1999) time-period. The outcomes for IVF newborns improved, especially for multiple births. After adjusting for mothers' background variables, the odds ratios for preterm birth and low birthweight decreased among singletons from 2.2 [95% confidence interval (CI) 1.8-2.8] to 1.8 (CI 1.5-2.1) and from 2.4 (CI 1.9-3.1) to 1.7 (CI 1.4-2.1) respectively and more among multiples from 2.4 (CI 2.0-2.9) to 1.5 (CI 1.2-1.7) and from 1.9 (CI 1.6-2.3) to 1.1 (CI 1.0-1.3) respectively. Still, overall the outcomes for IVF infants remained poorer than those for other infants. A correlation was found between increased use of antenatal services and improved outcomes, but causality cannot be assumed. CONCLUSION: A trend of improved perinatal health of multiple IVF children was found, mainly due to a decrease in higher order multiple births.

Adult↗

PubMed1998

Reproductive health outcomes among female flight attendants: an exploratory study.

Recent studies have suggested that female flight attendants may experience increased rates of spontaneous abortion. We conducted a survey of female flight attendants who were pregnant at any time between January 1, 1990, and December 31, 1991 (n = 418) using a mailed self-administered interest survey (response rate, 60 %) and follow-up questionnaire regarding reproductive outcomes and potential risk factors for adverse outcomes (response rate, 64%). The cumulative hazard of spontaneous abortion was 17% when maternal age, smoking, alcohol use, and prior spontaneous abortions were control led for, using a Cox life-table regression model. Of the female flight attendants who worked outside the home, 47 of 321 (15%) experienced a spontaneous abortion, compared with 6 of 73 (8%) who did not work outside the home during the pregnancy period (odds ratio [OR] = 1.91, 95 % confidence interval [CI] = 0.78-4.66). Flight attendants who experienced a spontaneous abortion during their first pregnancy during the study period reported working significantly more flight hours per month during their pregnancy (74 hours per month) than did flight attendants who delivered a live birth (64 hours per month) (Student's t = -3.30, P = 0.002). We conclude that although the results of this study must be considered preliminary because of the relatively low overall response rate (38%), we did not find an overall increased risk for spontaneous abortion among flight attendants, compared with other working women (10%-20%). Women who continue working as flight attendants during pregnancy and those who work relatively higher numbers of flight hours during pregnancy may, however, be at increased risk for spontaneous abortion, compared with flight attendants who do not perform such work.

Abortion, Spontaneous↗

PubMed1980

Serum levels of thyrotropin, thyroxine, 3,3',5-triiodothyronine and 3,3',5'-triiodothyronine (reverse T3) in the first six days of life.

Serum concentrations of thyrotropin (TSH), thyroxine (T4), 3,3',5-triiodothyronine (T3), and 3,3',5'-triiodothyronine (rT3) were determined in blood samples from 140 full-term healthy newborns, 110 appropriate weight and 30 large-for-gestational age, aged 1 to 6 days, delivered vaginally and breast-fed. Serum TSH levels decreased progressively from the 1st to the 4th day; serum T4 levels increased, with a peak on the 2nd day, and then progressively decreased until the 6th day; serum T3 levels increased to a maximum value on the 2nd day and then decreased to a minimum on the 5th day; serum rT3 levels increased during the 1st day and the level remained constant from the 2nd to the 4th day and later decreased slightly. The decrease of T3 was more pronounced than that of T4, while rT3 remained at high levels until the 4th day. Dividing the data into narrower intervals of time, it was possible to show that the maximum value of TSH was followed first by a net increase in serum T3, then in T4, and lastly in rT3 ant T3 levels. These data indicate that the rapid increase after birth of serum T3 levels is prevalently TSH-dependent; the following increase in serum levels of T3 and the increase in rT3 are prevalently T4-dependent. This study provides data concerning physiological changes in TSH and thyroid hormones in serum from a large number of infants, during the first week of life. They should be useful for the understanding of thyroid function in early postnatal life.

Age Factors↗