PubMed · 6843940
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K L Harkavy. 1983. Neonatal mortality statistics.. https://pubmed.ncbi.nlm.nih.gov/6843940/
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This review deals with retinopathy of prematurity (ROP), a disease characterized by retinovitreal neovascularization, eventually retinal detachment and blindness. Due to the increasing number of extremely premature newborns, it is becoming more frequent. ROP of all stages occurs in 25-35% of surviving premature newborns of gestational age up to approximately 35 weeks. Stages 3 or more occur in 5-10%, blindness in 3-5% of very immature babies. The incidence is inversely related to gestational age. Classification is internationally unified (ICROP) and describes 5 stages. Its pathogenesis has not yet been clarified. More or less proven risk factors are retinovascular immaturity, hyperoxia and possibly circulatory and respiratory instability. Prophylaxis consists in avoiding hyperoxia, and probably also in keeping the extremely premature newborn stable. Ophthalmologic examinations must be performed by ophthalmologists experienced in this field or under their direct responsibility and must be standardized. Treatment of ROP can be carried out at a certain stage by coagulation therapy.
OBJECTIVE: To establish reference ranges for recently developed assays of thyroid function in premature infants. METHODS: We measured serum free thyroxine (T4) by direct equilibrium dialysis and serum thyrotropin by a sensitive immunometric method in 104 preterm infants (25 to 36 weeks of gestational age) during the first week of life. RESULTS: The free T4 level correlated positively with gestational age (p < 0.0001; r2 = 0.09) and differed significantly between adjacent gestational age groups (p < 0.05). Free T4 concentrations (mean +/- SD) for the 25- to 27-, 28-to 30-, 31- to 33-, and 34- to 36-week groups were 18.0 +/- 5.2, 25.7 +/- 9.0, 30.9 +/- 9.0, 36.0 +/- 10.3 pmol/L (1.4 +/- 0.4, 2.0 +/- 0.7, 2.8 +/- 0.8 ng/dl), respectively. Two reference ranges for free T4 were determined, one for 25 to 30 weeks (6.4 to 42.5 pmol/L (0.5 to 3.3 ng/dl) and one for 31 to 36 weeks (16.7 to 60.5 pmol/L (1.3 to 4.7 ng/dl)). The logarithm of the value for thyrotropin correlated positively with gestational age (p < 0.001; r2 = 0.08); one reference range of 0.5 to 29 mU/L was determined for thyrotropin. CONCLUSION: This study extends information on thyroid function of preterm infants and establishes reference ranges for this population.
In humans, urine formation starts with the metanephros at the 10th week of gestation. Nephrogenesis progresses during gestation and is achieved around the 35th week. Clamping of the cord is the signal for a striking increase in renal function which reaches mature levels at the end of the first year of life. The integrity of several hormonal systems (the renin-angiotensin system, the prostaglandins) is mandatory for kidney growth and the development of renal function. The mechanisms underlying renal homeostasis are fragile and can easily be disturbed during respiratory and cardiovascular distress, or be affected by the administration of vasoactive agents. Thus, perinatal asphyxia or hypoxemia, as seen in respiratory distress syndrome or neonatal pulmonary hypertension induces intense renal vasoconstriction, with consequent oligoanuria. Congestive heart failure also results in renal hypoperfusion and sodium retention. Vasoactive agents and diuretics (indomethacin, tolazoline, furosemide) used to threat these conditions can result in renal vasoconstriction, renal hypoperfusion and failure. The pathogenesis and pathophysiology of neonatal renal disturbances being now better defined, a rational approach to the treatment of renal functional abnormalities during the neonatal period is possible.