Cryptorchidism or undescended testis is the single most common genitourinary disease in male neonates. In most cases, the testes will descend spontaneously by 3 months of age. If the testes do not descend by 6 months of age, the probability of spontaneous descent thereafter is low. About 1%–2% of boys older than 6 months have undescended testes after their early postnatal descent. In some cases, a testis vanishes in the abdomen or reascends after birth which was present in the scrotum at birth. An inguinal undescended testis is sometimes mistaken for an inguinal hernia. A surgical specialist referral is recommended if descent does not occur by 6 months, undescended testis is newly diagnosed after 6 months of age, or testicular torsion is suspected. International guidelines do not recommend ultrasonography or other diagnostic imaging because they cannot add diagnostic accuracy or change treatment. Routine hormonal therapy is not recommended for undescended testis due to a lack of evidence. Orchiopexy is recommended between 6 and 18 months at the latest to protect the fertility potential and decrease the risk of malignant changes. Patients with unilateral undescended testis have an infertility rate of up to 10%. This rate is even higher in patients with bilateral undescended testes, with intra-abdominal undescended testis, or who underwent delayed orchiopexy. Patients with undescended testis have a threefold increased risk of testicular cancer later in life compared to the general population. Self-examination after puberty is recommended to facilitate early cancer detection. A timely referral to a surgical specialist and timely surgical correction are the most important factors for decreasing infertility and testicular cancer rates.

Survivors of neonatal bronchopulmonary dysplasia (BPD) have persistent respiratory, neurodevelopmental, and growth impairment over the first few years of life and later childhood, which represents an emerging burden for health systems. Therefore, there is an increasing need for a new definition and grading system of BPD that predicts long-term outcomes of high-risk infants who need timely and proper intervention to improve outcomes. We compared new definitions of BPD (National Institute of Child Health and Human Development [NICHD] 2018 and Neonatal Research Network [NRN] 2019) to the original NICHD 2001 definition at 3 years of age using a nationwide cohort of extreme preterm infants. New definitions and severity grading were clearly related to respiratory, neurodevelopmental, and growth impairments at 3 years of age and at 18–24 months corrected age (CA), whereas the original NICHD 2001 definition was not. Furthermore, the negative effect of BPD on growth was ameliorated at 3 years of age compared to 18–24 months CA. However, the negative effect of BPD in neonates on the respiratory system and neurodevelopment persisted at 3 years of age. These new definitions should be adopted to identify high-risk infants and improve long-term outcomes by exact diagnosis and BPD severity classification.

Following the first successful trial of surfactant replacement therapy for preterm infants with respiratory distress syndrome (RDS) by Fujiwara in 1980, several animal-derived natural surfactants and synthetic surfactants have been developed. Synthetic surfactants were designed to overcome limitations of natural surfactants such as cost, immune reactions, and infections elicited by animal proteins contained in natural surfactants. However, first-generation synthetic surfactants that are protein-free have failed to prove their superiority over natural surfactants because they lack surfactant protein (SP). Lucinactant, a second-generation synthetic surfactant containing the SP-B analog, was better or at least as effective as the natural surfactant, suggesting that lucinactant could act an alternative to natural surfactants. Lucinactant was approved by the U. S. Food and Drug Administration in March 2012 as the fifth surfactant to treat neonatal RDS. CHF5633, a second-generation synthetic surfactant containing SP-B and SP-C analogs, was effective and safe in a human multicenter cohort study for preterm infants. Many comparative studies of natural surfactants used worldwide have reported different efficacies for different preparations. However, these differences are believed to due to site variations, not actual differences. The more important thing than the composition of the surfactant in improving outcome is the timing and mode of administration of the surfactant. Novel synthetic surfactants containing synthetic phospholipid incorporated with SP-B and SP-C analogs will potentially represent alternatives to natural surfactants in the future, while improvement of treatment modalities with less-invasive or noninvasive methods of surfactant administration will be the most important task to be resolved.

New definitions for bronchopulmonary dysplasia (BPD) have recently been suggested, and an accurate diagnosis, including severity classification with proper definition, is crucial to identify high-risk infants for appropriate interventions. To determine whether recently suggested BPD definitions can better predict long-term outcomes of BPD in extremely preterm infants (EPIs) than the original BPD definition, BPD was classified with severity 1, 2, and 3 using three different definitions: definition A (original), National Institute of Child Health and Human Development (NICHD) definition in 2001; definition B, the modified NICHD 2016 definition (graded by the oxygen concentration and the respiratory support at 36 weeks’ postmenstrual age [PMA]); and definition C, the modified Jensen 2019 definition (graded by the respiratory support at 36 weeks’ PMA). We evaluated 1050 EPIs using a national cohort. Whereas EPIs with grade 2 or 3 BPD as per definition A did not show any increase in the risk, EPIs with BPD diagnosed by definition B and C showed significantly increased risk for poor outcomes, such as respiratory mortality and morbidities, neurodevelopmental delay, and growth restriction at 18–24 months of corrected age. The recently suggested definition and severity grading better reflects long-term childhood morbidities than the original definition in EPIs.

Thyroid dysfunction is common in preterm infants. Congenital hypothyroidism causes neurodevelopmental impairment, which is preventable if properly treated. This study was conducted to describe the characteristics of thyroid dysfunction in very low birth weight infants (VLBWIs), evaluate risk factors of hypothyroidism, and suggest the reassessment of thyroid function with an initially normal thyroid-stimulating hormone (TSH) as part of a newborn screening test. VLBWIs (January 2010 to December 2012) were divided into two groups according to dysfunction-specific thyroid hormone replacement therapy, and associated factors were evaluated. Of VLBWIs, 246 survivors were enrolled. Only 12.2% (30/246) of enrolled subjects exhibited thyroid dysfunction requiring thyroid hormone replacement. Moreover, only one out of 30 subjects who required thyroid hormone treatment had abnormal thyroid function in the newborn screening test with measured TSH. Most of the subjects in the treatment group (22/30) exhibited delayed TSH elevation. Gestational age, Apgar score, antenatal steroids therapy, respiratory distress syndrome, patent ductus arteriosus, sepsis, intraventricular hemorrhage, postnatal steroids therapy, and duration of mechanical ventilation did not differ between the two groups. Birth weight was smaller and infants with small for gestational age were more frequent in the treatment group. Physicians should not rule out suggested hypothyroidism, even when thyroid function of a newborn screening test is normal. We suggest retesting TSH and free thyroxine in high risk preterm infants with an initially normal TSH level using a newborn screening test.