The impact of the COVID-19 pandemic on infant obesity: A nationwide retrospective cohort study.

BACKGROUND: Lifestyle changes, such as those related to the COVID-19 pandemic, including alterations in physical activity and dietary habits, are known to affect pregnancy outcomes. In particular, suboptimal intrauterine conditions during pregnancy are known to influence not only fetal growth but also growth during infancy. However, research on the impact of the environmental changes caused by the COVID-19 pandemic on the growth of infants and children during their early years is lacking. To address this issue, this study evaluated the effect of the COVID-19 pandemic on obesity in infants. METHODS: This retrospective cohort study used the data collected from the Korea National Health Insurance (KNHI) claims database. The data of 1985,678 women who delivered infants between 2015 and 2021 were collected. Women who delivered during the pandemic and those who delivered during the pre-pandemic period were matched in a 1:1 frequency-matched pair procedure for factors such as age, hypertension, diabetes mellitus, preeclampsia, gestational diabetes mellitus, mode of delivery, gestational age at delivery, offspring sex, and birth weight. Finally, 197,580 women were enrolled. The weight and head circumference of infants (4-6 months of age) of the COVID-19 pandemic group were compared with those of the pre-pandemic group. RESULTS: The COVID-19 pandemic group infants exhibited significantly higher weight and prevalence of obesity at 4-6 months of age compared to infants in the pre-pandemic group. After adjustment for covariates, pandemic group infants had a higher risk of obesity (odds ratio: 1.54, 95% confidence interval: 1.51-1.57) compared to the pre-pandemic group infants. CONCLUSION: The COVID-19 pandemic has had a notable impact on the weight of infants aged 4-6 months. This suggests that pandemic conditions may influence the growth of newborns, underscoring the importance of monitoring and assessing trends in the growth of infants born during such crises.

Homemade weaning foods as a source of lead and mercury exposure in Korean infants - A dietary risk assessment study.

Lead (Pb) and mercury (Hg) are neurodevelopmental toxicants that pose risks to cognitive and behavioral health. Given early childhood's vulnerability to these metals, understanding their sources and pathways of exposure during infancy is crucial for public health. During the weaning process, infants may be exposed to metals through the baby food they consume. We aimed to assess metal exposure through homemade weaning foods by analyzing 288 samples consumed by 157 Korean infants aged 6-, 9-, 12-, 15-, and 24-27 months. Pb was detected in 65 % of samples, with levels reaching up to 169 ng/g. Notably, 58 % exceeded the Maximum Level (ML) of 10 ng/g, with a median concentration of 14.7 ng/g fresh weight. Total Hg was found in 88 % of samples, with a median concentration of 4.56 ng/g fresh weight. Estimated median daily intakes of Pb and Hg were 0.29 and 0.09 µg/kg/d, respectively. Considering a benchmark dose for Pb (0.5 µg/kg/d by EFSA), 94 % (the margin of exposure <10) of all age groups was estimated to have a potential health concern associated with homemade baby food consumption. For Hg, only 6 % exceeded a hazard quotients of 1 compared to a provisional tolerable weekly intake for Hg (4 µg/kg/week by WHO). This study marks the first direct assessment of daily Pb and Hg intake through homemade baby food among Korean infants. Our findings underscore the urgent need for heightened awareness regarding metal exposure through homemade baby food.

The Risk of Hypertension and Diabetes Mellitus According to Offspring's Birthweight in Women With Normal Body Mass Index: A Nationwide Population-Based Study.

BACKGROUND: Maladaptation to vascular, metabolic, and physiological changes during pregnancy can lead to fetal growth disorders. Moreover, adverse outcomes during pregnancy can further increase the risk of cardiovascular and metabolic diseases in mothers. Delivering a large-for-gestational-age (LGA) baby may indicate a pre-existing metabolic dysfunction, whereas delivering a small-for-gestational-age (SGA) baby may indicate a pre-existing vascular dysfunction. This study aims to assess the risk of hypertension (HTN) and diabetes mellitus (DM) in women with normal body mass index (BMI) scores who did not experience gestational DM or hypertensive disorders during pregnancy based on the offspring's birthweight. METHODS: This retrospective nationwide study included women with normal BMI scores who delivered a singleton baby after 37 weeks. Women with a history of DM or HTN before pregnancy and those with gestational DM or hypertensive disorders, were excluded from the study. We compared the risk of future maternal outcomes (HTN and DM) according to the offspring's birthweight. Multivariate analyses were performed to estimate the hazard ratio (HR) for the future risk of HTN or DM. RESULTS: A total of 64,037 women were included in the analysis. Of these, women who delivered very LGA babies (birthweight > 97th percentile) were at a higher risk of developing DM than those who delivered appropriate-for-gestational-age (AGA) babies (adjusted HR = 1.358 [1.068-1.727]), and women who delivered very SGA babies (birthweight < 3rd percentile) were at a higher risk of developing HTN than those who delivered AGA babies (adjusted HR = 1.431 [1.181-1.734]), even after adjusting for age, parity, gestational age at delivery, fetal sex, maternal BMI score, and a history of smoking. CONCLUSION: These findings provide a novel support for the use of the offspring's birthweight as a predictor of future maternal diseases such as HTN and DM.

Enhancing Cervical Cancer Screening: Review of p16/Ki-67 Dual Staining as a Promising Triage Strategy.

Cervical cancer, primarily caused by high-risk human papillomavirus (HR-HPV) types 16 and 18, is a major global health concern. Persistent HR-HPV infection can progress from reversible precancerous lesions to invasive cervical cancer, which is driven by the oncogenic activity of human papillomavirus (HPV) genes, particularly E6 and E7. Traditional screening methods, including cytology and HPV testing, have limited sensitivity and specificity. This review explores the application of p16/Ki-67 dual-staining cytology for cervical cancer screening. This advanced immunocytochemical method allows for simultaneously detecting p16 and Ki-67 proteins within cervical epithelial cells, offering a more specific approach for triaging HPV-positive women. Dual staining and traditional methods are compared, demonstrating their high sensitivity and negative predictive value but low specificity. The increased sensitivity of dual staining results in higher detection rates of CIN2+ lesions, which is crucial for preventing cervical cancer progression. However, its low specificity may lead to increased false-positive results and unnecessary biopsies. The implications of integrating dual staining into contemporary screening strategies, particularly considering the evolving landscape of HPV vaccination and changes in HPV genotype prevalence, are also discussed. New guidelines and further research are necessary to elucidate the long-term effects of integrating dual staining into screening protocols.

Ultrasonographic assessment of abnormal fetal growth related to uteroplacental-fetal biometrics and Doppler (U-AID) indices: Protocol for multicenter retrospective cohort study trial.

Fetal growth restriction (FGR) is one of the leading causes of perinatal morbidity and mortality. Many studies have reported an association between FGR and fetal Doppler indices focusing on umbilical artery (UA), middle cerebral artery (MCA), and ductus venosus (DV). The uteroplacental-fetal circulation which affects the fetal growth consists of not only UA, MCA, and DV, but also umbilical vein (UV), placenta and uterus itself. Nevertheless, there is a paucity of large-scale cohort studies that have assessed the association between UV, uterine wall, and placental thickness with perinatal outcomes in FGR, in conjunction with all components of the uteroplacental-fetal circulation. Therefore, this multicenter study will evaluate the association among UV absolute flow, placental thickness, and uterine wall thickness and adverse perinatal outcome in FGR fetuses. This multicenter retrospective cohort study will include singleton pregnant women who undergo at least one routine fetal ultrasound scan during routine antepartum care. Pregnant women with fetuses having structural or chromosomal abnormalities will be excluded. The U-AID indices (UtA, UA, MCA, and UV flow, placental and uterine wall thickness, and estimated fetal body weight) will be measured during each trimester of pregnancy. The study population will be divided into two groups: (1) FGR group (pregnant women with FGR fetuses) and (2) control group (those with normal growth fetus). We will assess the association between U-AID indices and adverse perinatal outcomes in the FGR group and the difference in U-AID indices between the two groups.

The Role of the Aryl Hydrocarbon Receptor in Vascular Factors Related to Preeclampsia in a Smoking Mouse Model.

Smoking cigarettes is known to lower the risk of preeclampsia. The objective of this study is to evaluate the effect of smoking on the expression of soluble FMS-like tyrosine kinase-1 (sFlt-1), vascular endothelial growth factor (VEGF), and endoglin (sEng)-1 and the role of the aryl hydrocarbon receptor (AhR) in pregnant mice. We developed a smoking mouse model using a gas-filling system. One or two cigarettes per day were exposed to each of the five pregnant mice for five days a week throughout pregnancy. AhR agonist and antagonist were injected. Serum levels and expression in the placenta of sFlt-1, VEGF, and sEng-1 were analyzed and compared among the cigarette smoke and no-exposure groups after delivery. Compared to the no-smoke exposure group, the serum level of sFlt-1 was significantly decreased in the two-cigarette-exposed group (p < 0.001). When the AhR antagonist was added to the two-cigarette-exposed group, sFlt-1 levels were significantly increased compared to the two-cigarette group (p = 0.002). The levels of sFlt-1 in the AhR antagonist group did not change regardless of two-cigarette exposure (p = 0.064). With the AhR agonist, sFlt-1 decreased significantly compared to the control (p = 0.001) and AhR antagonist group (p = 0.002). The sFlt-1 level was significantly decreased after the injection of the AhR agonist compared to the control group (p = 0.001). Serum levels of VEGF were significantly decreased in the one-cigarette-exposed group compared to the control group; however, there was no difference between the control and the two-cigarette-exposed groups. The placental expression of sFlt-1, VEGF, and sEng were inconsistent. This study offers insights into the potential role of AhR on antiangiogenic sFlt-1 associated with preeclampsia. It may support the invention of a new treatment strategy for preeclampsia using AhR activation.

Short-term neonatal and long-term neurodevelopmental outcome of children born term low birth weight.

This study aimed to examine the impact of term LBW on short-term neonatal and long-term neurodevelopmental outcomes in children 5-7 years of age. This is a population-based cohort study that merged national data from the Korea National Health Insurance claims and National Health Screening Program for Infants and Children. The participants were women who gave birth at a gestational age of ≥ 37 weeks between 2013 and 2015 in the Republic of Korea, and were tracked during 2020 for the neurodevelopmental surveillance of their children. Among 830,806 women who gave birth during the study period, 31,700 (3.8%) of their babies weighed less than 2500 g. By Cox proportional hazard analysis, children aged 5-7 years who had LBW were associated with any developmental, motor developmental delay, cognitive developmental delay, autism spectrum, attention deficit hyperactivity disorders, and epileptic and febrile seizures.Children born with term LBW were more vulnerable to neurodevelopmental disorders at 5-7 years of age than those with normal and large birth weights. This study further substantiates counseling parents regarding the long-term outcomes of children being born underweight.

Prepregnancy Glucose Levels Within Normal Range and Its Impact on Obstetric Complications in Subsequent Pregnancy: A Population Cohort Study.

BACKGROUND: We sought to identify the influence of prepregnancy glucose levels on obstetric complications in subsequent pregnancy. METHODS: Women in Republic of Korea who had given birth between January 1st, 2007 and December 31st, 2010 were enrolled. The database of the Health Insurance Review and Assessment Service and data from a national health screening program for infants and children were used. Subjects were divided into seven groups according to their fasting glucose levels. RESULTS: 59,619 women were included for analysis, and 10.4%, 13.7%, 19.1%, 21.5%, 16.0%, 11.6%, and 7.5% women had glucose levels of < 75, 75-79, 80-84, 85-89, 90-94, 95-100 and > 100 mg/dL. Each 5 mg/dL increase in prepregnancy fasting glucose levels was associated with increased risk of gestational diabetes and macrosomia in subsequent pregnancy. Adjusted risk ratio for gestational diabetes per standard deviation prepregnancy glucose > 100 mg/dL was 2.015 (95% confidence interval, 1.649-2.462) and for macrosomia an adjusted risk ratio 1.389 (95% confidence interval, 1.147-1.682). CONCLUSION: Higher prepregnancy glucose level within normal range was related to gestational diabetes and macrosomia in following pregnancy. Our results may aid in the identification of women at future risk of obstetric complications and may guide to stratify women into normal and intensified care. TWEETABLE ABSTRACT: Higher prepregnancy glucose in normal range is associated with gestational diabetes and macrosomia.

Bioinformatics and integrated pharmacology network to identify the therapeutic targets and potential molecular mechanism of alpha-lipoic acid on primary ovarian insufficiency.

Women experiencing primary ovarian insufficiency (POI) are more likely to experience infertility, and its incidence is increasing worldwide annually. Recently, the role of alpha-lipoic acid (ALA) in the treatment of POI has been reported. However, details of the potential pharmacological targets and related molecular pathways of ALA remain unclear and need to be elucidated. Thus, this study aims to elucidate the potential therapeutic target and related molecular mechanism of ALA on POI. First, the potential targets of POI and ALA-related targets were downloaded from online public databases. Subsequently, the overlapped target genes between POI and ALA were acquired, and gene ontology (GO), Kyoto encyclopedia of genes and genomes (KEGG) analysis, protein-protein interaction (PPI) networks were performed and constructed. Finally, molecular docking was performed to verify protein-to-protein effect. A total of 152 potential therapeutic targets were identified. The biological processes of the intersecting targets were mainly involved in the cellular response to peptides, response to xenobiotic stimuli, and response to peptide hormones. The highly enriched pathways were the cAMP, PI3K/AKT, estrogen, progesterone mediated oocyte maturation, and apoptosis signaling pathways. The top 10 hub targets for ALA in the treatment of POI were STAT3, STAT1, CASP3, MTOR, PTGS2, CASP8, HSP90AA1, PIK3CA, MAPK1, and ESR1. The binding between ALA and all top hub targets were verified using the molecular docking analysis. In summary, using the systematic integrated pharmacology network and bioinformatics analysis, this study illustrated that ALA participates in the treatment of POI via multiple targets and multiple pathways mechanisms.

Patient blood management to minimize transfusions during the postpartum period.

Patient blood management is an evidence-based concept that seeks to minimize blood loss by maintaining adequate hemoglobin levels and optimizing hemostasis during surgery. Since the coronavirus disease 2019 pandemic, patient blood management has gained significance due to fewer blood donations and reduced amounts of blood stored for transfusion. Recently, the prevalence of postpartum hemorrhage (PPH), as well as the frequency of PPH-associated transfusions, has steadily increased. Therefore, proper blood transfusion is required to minimize PPH-associated complications while saving the patient's life. Several guidelines have attempted to apply this concept to minimize anemia during pregnancy and bleeding during delivery, prevent bleeding after delivery, and optimize recovery methods from anemia. This study systematically reviewed various guidelines to determine blood loss management in pregnant women.

Investigating the regenerative effects of folic acid on human amniotic epithelial stem cells and amniotic pore culture technique (APCT) model in vitro using an integrated pharmacological-bioinformatic approach.

INTRODUCTION: Disruption of fetal membranes before the onset of labor is referred to as premature rupture of membranes (PROM). Lack of maternal folic acid (FA) supplementation reportedly leads to PROM. However, there is a lack of information on the location of FA receptors in the amniotic tissue. Additionally, the regulatory role and potential molecular targets of FA in PROM in vitro have rarely been investigated. METHODS: The three FA receptors (folate receptor α isoform [FRα], transporter of reduced folate [RFC], and proton-coupled folate transporter [PCFT]) in human amniotic epithelial stem cells (hAESCs) and amniotic tissue were localized using immunohistochemistry and immunocytochemistry staining. Effect and mechanism analyses of FA were performed in hAESCs and amniotic pore culture technique (APCT) models. An integrated pharmacological-bioinformatics approach was utilized to explore the potential targets of FA for the treatment of PROM. RESULTS: The three FA receptors were widely expressed in human amniotic tissue, especially in the hAESC cytoplasm. FA stimulated the amnion regeneration in the in vitro APCT model. This mimics the PROM status, in which cystathionine-ß-synthase, an FA metabolite enzyme, may play an important role. The top ten hub targets (STAT1, mTOR, PIK3R1, PTPN11, PDGFRB, ABL1, CXCR4, NFKB1, HDAC1, and HDAC2) of FA for preventing PROM were identified using an integrated pharmacological-bioinformatic approach. DISCUSSION: FRα, RFC, and PCFT are widely expressed in human amniotic tissue and hAESCs. FA aids the healing of ruptured membrane.

Pregnancy outcomes in twin pregnancies over 10 years.

OBJECTIVE: The aim of this study was to evaluate the changes in twin pregnancy outcomes between 2007 and 2016 in a Korean population. METHODS: The data for this nationwide population-based study was obtained from the national birth registry of the Korean National Statistical Office and the Health Insurance Review & Assessment Service of Korea. Women with twin pregnancies who gave birth between 2007 and 2016 were included. RESULTS: From 2007 to 2016, the rate of twin pregnancies increased (1.37% vs. 1.91%, respectively, P<0.0001). The risk of preterm birth (adjusted odds ratio [aOR], 1.77; 95% confidence interval [CI], 1.66-1.89) also increased; however, the risk of twin growth discordance (aOR, 0.90; 95% CI, 0.82-0.99) decreased. The risks of cesarean section (aOR, 1.16; 95% CI, 1.03-1.29), gestational diabetes mellitus (aOR, 2.10; 95% CI, 1.83-2.39), and postpartum hemorrhage (aOR, 1.27; 95% CI, 1.14-1.41) all increased from 2007 to 2016. CONCLUSION: Twin pregnancy outcomes have changed significantly in Korea over a recent 10-year period.

Correction: Kim et al. The Value of Posterior Cervical Angle as a Predictor of Vaginal Delivery: A Preliminary Study. Diagnostics 2021, 11, 1977.

In the original publication [...].

Effect of Fibronectin on Cervical Excision and Lipopolysaccharide-Induced Inflammation-Related Preterm Delivery.

In our previous study, preterm birth after pre-pregnancy partial cervical excision demonstrated abnormal wound healing with an increased muscle-to-collagen ratio at the proximal site of the cervix. We aimed to investigate whether treatment with plasma fibronectin affects the differentiation of mouse uterine cervical fibroblasts into myofibroblasts and mediates a reduction in the incidence of preterm delivery in mice. We examined the gestational period after the administration of lipopolysaccharide in mice subjected to cervical excision and subsequently treated with fibronectin or vehicle. We confirmed that the gestational period was longer in the plasma fibronectin-treated group than in the vehicle-treated control group. In addition, the ratio of α-smooth muscle actin to collagen type I alpha 1 increased after LPS injection in mice subjected to cervical excision, and this increase was suppressed by plasma fibronectin treatment. Plasma fibronectin may serve as a potential therapeutic agent to prevent preterm delivery by inhibiting myogenic differentiation in the cervix.

The Value of Posterior Cervical Angle as a Predictor of Vaginal Delivery: A Preliminary Study.

Accurate prediction of failure to progress and rapid decision making regarding the mode of delivery can improve pregnancy outcomes. We examined the value of sonographic cervical markers in the prediction of successful vaginal delivery beyond 34 weeks of gestation. A retrospective chart review was carried out. Medical information of singleton gestations delivered at a single center from 1 July 2019 to 30 August 2020 was collected. Transvaginal sonographic records of cervical length, anterior and posterior cervical angles, and cervical dilatation were obtained and re-measured. The value of these markers and clinical characteristics of mother and baby on vaginal delivery were investigated and compared to women who underwent cesarean section. A total of 90 women met the inclusion criteria. The rate of vaginal delivery was 75.6%. There were no differences found in terms of maternal age, rate of abortion, induction of labor, premature rupture of membranes, preterm labor, hypertension, diabetes, cervical length, and neonatal sex and weight. The prediction of vaginal delivery was provided by parity, maternal body mass index, and posterior cervical angle. The area under the receiver operating characteristic curve for prediction of vaginal delivery was 0.667 (95% CI 0.581-0.864, p = 0.017) for the posterior cervical angle, with a cutoff of 96.5°. Regression analysis revealed a posterior cervical angle ≥96.5° in the prediction of vaginal delivery (adjusted odds ratio: 6.24; 95% confidence interval: 1.925-20.230, p = 0.002). Posterior cervical angle ≥96.5° is associated with successful vaginal delivery. It is simple and easy to measure and can be useful in determining the mode of delivery.

Women with multiple gestations have an increased risk of development of hypertension in the future.

BACKGROUND: Multiple gestations are associated with an increased incidence of preeclampsia. However, there exists no evidence for an association between multiple gestations and development of hypertension(HTN) later in life. This study aimed to determine whether multiple gestations are associated with HTN beyond the peripartum period. METHODS: In this retrospective nationwide population-based study, women who delivered a baby between January 1, 2007, and December 31, 2008, and underwent a national health screening examination within one year prior to their pregnancy were included. Subsequently, we tracked the occurrence of HTN during follow-up until December 31, 2015, using International Classification of Diseases-10th Revision codes. RESULTS: Among 362,821 women who gave birth during the study period, 4,944 (1.36%) women had multiple gestations. The cumulative incidence of HTN was higher in multiple gestations group compared with singleton group (5.95% vs. 3.78%, p < 0.01, respectively). On the Cox proportional hazards models, the risk of HTN was increased in women with multiple gestations (HR 1.35, 95% CI 1.19, 1.54) compared with those with singleton after adjustment for age, primiparity, preeclampsia, atrial fibrillation, body mass index, blood pressure, diabetes mellitus, high total cholesterol, abnormal liver function test, regular exercise, and smoking status. CONCLUSIONS: Multiple gestations are associated with an increased risk of HTN later in life. Therefore, guidelines for the management of high-risk patients after delivery should be established.

Association of Preterm Birth with Depression and Particulate Matter: Machine Learning Analysis Using National Health Insurance Data.

This study uses machine learning and population data to analyze major determinants of preterm birth including depression and particulate matter. Retrospective cohort data came from Korea National Health Insurance Service claims data for 405,586 women who were aged 25-40 years and gave births for the first time after a singleton pregnancy during 2015-2017. The dependent variable was preterm birth during 2015-2017 and 90 independent variables were included (demographic/socioeconomic information, particulate matter, disease information, medication history, obstetric information). Random forest variable importance was used to identify major determinants of preterm birth including depression and particulate matter. Based on random forest variable importance, the top 40 determinants of preterm birth during 2015-2017 included socioeconomic status, age, proton pump inhibitor, benzodiazepine, tricyclic antidepressant, sleeping pills, progesterone, gastroesophageal reflux disease (GERD) for the years 2002-2014, particulate matter for the months January-December 2014, region, myoma uteri, diabetes for the years 2013-2014 and depression for the years 2011-2014. In conclusion, preterm birth has strong associations with depression and particulate matter. What is really needed for effective prenatal care is strong intervention for particulate matters together with active counseling and medication for common depressive symptoms (neglected by pregnant women).

Changes in gene expression of cervical collagens, metalloproteinases, and tissue inhibitors of metalloproteinases after partial cervical excision-induced preterm labor in mice.

We investigated changes in gene expression of cervical collagens, matrix metalloproteinases (MMPs), and tissue inhibitors of metalloproteinases (TIMPs) during pre-gestational uterine cervical excision and/or inflammation-induced preterm labor in mice. Forty sexually mature female mice were uniformly divided into four groups: sham, cervical excision, lipopolysaccharide (LPS) injection, and cervical excision plus LPS injection. Partial cervical tissue excision was performed at five weeks of age before mating. LPS was injected into the lower right uterine horn near the cervix on gestational day 16. Mice were sacrificed immediately postpartum. Uterine cervices were collected and subjected to quantitative real-time PCR. Col4α1 and Col5α1 expression increased significantly in the cervical excision plus LPS injection group compared to the sham group (p < 0.01 and p = 0.024, respectively). MMP-14 expression levels increased in the cervical excision plus LPS injection group compared to the sham group (p < 0.01). TIMP-1 expression was not significantly decreased in this group. Increased expression levels of Col4α1, Col5α1, and MMP-14 were associated with cervical excision plus inflammation-induced preterm labor. Thus, pre-gestational cervical remodeling through specific collagen metabolism and MMP activation may involve the pathogenesis of spontaneous preterm labor.

Perinatal Outcomes Associated with Latency in Late Preterm Premature Rupture of Membranes.

This study aims to evaluate the perinatal outcomes of preterm premature rupture of membrane (PPROM) with latency periods at 33 + 0-36 + 6 weeks of gestation. This retrospective case-control study included women with singleton pregnancies who delivered at 33 + 0-36 + 6 weeks at Korea University Ansan Hospital in South Korea between 2006-2019. The maternal and neonatal characteristics were compared between different latency periods (expectant delivery ≥72 h vs. immediate delivery <72 h). Data were compared among 345 women (expectant, n = 39; immediate delivery, n = 306). There was no significant difference in maternal and neonatal morbidities between the groups, despite the younger gestational age in the expectant delivery group. Stratified by gestational weeks, the 34-week infants showed a statistically significant lower exposure to antenatal steroids (73.4% vs. 20.0%, p < 0.001), while the incidence of respiratory distress syndrome (12.8%) and the use of any respiratory support (36.8%) was higher than those in the 33-week infants, without significance. Our study shows that a prolonged latency period (≥72 h) did not increase maternal and neonatal morbidities, and a considerable number of preterm infants immediately delivered at 34 weeks experienced respiratory complications. Expectant management and antenatal corticosteroids should be considered in late preterm infants with PPROM.