Heme oxygenase (HO) is the rate-limiting enzyme in the heme catabolic pathway, which degrades heme into equimolar amounts of carbon monoxide, free iron, and biliverdin. Its inducible isoform, HO-1, has multiple protective functions, including immune modulation and pregnancy maintenance, showing dynamic alteration during perinatal periods. As its contribution to the development of perinatal complications is speculated, two functional polymorphisms of the HMOX1 gene, (GT)n repeat polymorphism (rs3074372) and A(-413)T single nucleotide polymorphism (SNP) (rs2071746), were studied for their association with perinatal diseases. We systematically reviewed published evidence on HMOX1 polymorphisms in perinatal diseases and clarified their possible significant contribution to neonatal jaundice development, presumably due to their direct effect of inducing HO enzymatic activity in the bilirubin-producing pathway. However, the role of these polymorphisms seems limited for other perinatal complications such as bronchopulmonary dysplasia. We speculate that this is because the antioxidant or anti-inflammatory effect is not directly mediated by HO but by its byproducts, resulting in a milder effect. For better understanding, subtyping each morbidity by the level of exposure to causative environmental factors, simultaneous analysis of both polymorphisms, and the unified definition of short and long alleles in (GT)n repeats based on transcriptional capacity should be further investigated.

This study aimed to investigate the long-term changes in awareness of and knowledge about mother-to-child infections across 6 years in Japan. A questionnaire survey was conducted at our facility from October 2012 to January 2018, and the study periods were divided into 4 phases comprising 16 months each. A multiple-choice questionnaire assessed participants’ awareness of the following 13 pathogens of mother-to-child infections: cytomegalovirus (CMV), Toxoplasma gondii (T. gondii), hepatitis B virus, rubella virus, herpes simplex virus, parvovirus B19, hepatitis C virus, human immunodeficiency virus, human T cell leukemia virus type-1, measles virus, varicella-zoster virus, Chlamydia trachomatis, and Treponema pallidum. For the selected four pathogens (i.e., CMV, rubella virus, T. gondii, and parvovirus B19), the questionnaire also evaluated participants’ knowledge of transmission routes, the most susceptible time of infection that could yield severe fetal disease during pregnancy, the maximum frequency of fetal infection in cases of maternal infection, and methods to prevent maternal infection. In total, 1433 pregnant Japanese women were included in this study. There was no secular change in awareness of the pathogens concerning mother-to-child infections over time, and we also clarified that the detailed knowledge of the four pathogens of typical mother-to-child infections did not improve. Since knowledge about methods to prevent maternal infection is still insufficient for all pathogens, further advocacy is required to prevent mother-to-child infections.

No abstract

Although preterm infant mortality is low, the proportion of patients with treatment-requiring retinopathy of prematurity (TR-ROP) is high in Japan. Various multicenter studies have reported the risk factors for TR-ROP; however, no large-scale studies have been conducted in Japan. We retrospectively analyzed 13,645 infants born at < 28 weeks’ gestation (January 1, 2009–December 31, 2018), and registered in the Neonatal Research Network of Japan database. TR-ROP was defined as ROP requiring retinal laser photocoagulation and/or intravitreal anti-vasoendothelial growth factor drugs. Multivariable logistic regression analysis was performed to identify factors associated with TR-ROP development. The median gestational age of enrolled infants was 26 weeks (interquartile range [IQR], 24–27 weeks), median birth weight was 760 g (IQR, 620–918 g). Proportion of patients with TR-ROP was 30.3%. TR-ROP was significantly associated with birth at < 26 weeks’ gestational age (adjusted odds ratio [aOR] 1.54), blood transfusion (aOR 1.49), invasive ventilation ≥ 28 days (aOR 1.41), sepsis (aOR 1.29), birth weight < 750 g (aOR 1.28), intraventricular hemorrhage (aOR 1.33), delayed achievement of full enteral feeding > 14 days (aOR 1.28), and continuous positive airway pressure (CPAP) therapy ≥ 28 days (aOR 0.79). Supplemental oxygen ≥ 28 days was not associated with TR-ROP development. Lower gestational age at birth and birth weight, blood transfusion, prolonged invasive ventilation, sepsis, intraventricular hemorrhage, and delayed achievement of full enteral feeding were risk factors for TR-ROP, whereas CPAP use was protective against TR-ROP.

Severe small-for-gestational-age (sSGA) infants exhibit increased mortality and morbidity. Oxidative stress is suggested to be involved in intrauterine growth restriction. This retrospective study aimed to evaluate the oxidative stress level at birth in an sSGA population. Sera of 28 sSGA (sSGA group) and 31 non-sSGA (control group) infants, born at our hospital between March 2017 and March 2020, were evaluated. Oxidative stress (derivative of reactive oxidative metabolites: d-ROM level), biological antioxidant potential (BAP) level, and the ratio of d-ROM/BAP level (oxidative stress index: OSI) were measured. The sSGA group had a significantly lower birth weight (BW), BW z-score, head circumference, and height than the control group (all p < 0.05). No significant difference was noted in the BAP level; sSGA infants exhibited a significantly higher d-ROM level than control infants. sSGA infants showed a significantly increased OSI compared with control infants, and the BW z-score was inversely correlated with d-ROM levels and OSI in sSGA infants (R2 = 0.300; p < 0.01 and R2 = 0.319; p = 0.02, respectively) but not in controls. In conclusion, sSGA infants, including preterm infants, exhibited higher oxidative stress at birth. The severity of fetal growth restriction was significantly correlated with oxidative stress levels at birth in sSGA infants.