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.

The safety of progestogen in the prevention of preterm birth: meta-analysis of neonatal mortality.

BACKGROUND: The safety of preventive progestogen therapy for preterm birth remains to be established. This meta-analysis aimed to evaluate the effects of preventive progestogen therapy on neonatal mortality. METHODS: Randomized controlled trials (RCTs) on the preventive use of progestogen therapy, published between October 1971 and November 2015, were identified by searching MEDLINE/PubMed, EMBASE, Scopus, ClinicalTrials.gov, Cochrane Library databases, CINAHL, POPLINE, and LILACS using "progesterone" and "preterm birth" as key terms. We conducted separate analyses according to the type of progestogen administered and plurality of the pregnancy. RESULTS: Twenty-two RCTs provided data on 11,188 neonates. Preventive progestogen treatment in women with a history of preterm birth or short cervical length was not associated with increased risk of neonatal death compared to placebo in all analyzed progestogen types and pregnancy conditions. The pooled relative risks (95% confidence interval) of neonatal mortality were 0.69 (0.31-1.54) for vaginal progestogen in singleton pregnancies, 0.6 (0.33-1.09) for intramuscular progestogen in singleton pregnancies, 0.96 (0.51-1.8) for vaginal progestogen in multiple pregnancies, and 0.96 (0.49-1.9) for intramuscular progestogen in multiple pregnancies. CONCLUSIONS: The results of this meta-analysis suggest that administration of preventive progestogen treatment to women at risk for preterm birth does not appear to negatively affect neonatal mortality in single or multiple pregnancies regardless of the route of administration.

Occurrence and prenatal exposure to persistent organic pollutants using meconium in Korea: Feasibility of meconium as a non-invasive human matrix.

Prenatal exposure to persistent organic pollutants (POPs) is of great concern due to the vulnerability of fetus. Nineteen Polychlorinated biphenyls (PCBs), 18 organochlorine pesticides (OCPs) including DDTs, HCHs, chlordanes, and hexachlorobenzene, and 22 polybrominated diphenyl ethers (PBDEs) were measured in meconium samples from 72 newborn infants using high resolution gas chromatography/mass spectrometry. The median concentrations (on wet weight basis) of PCBs, OCPs, and PBDEs were 26.8pg/g, 66.7pg/g, and 2.32pg/g, respectively. Highly significant correlations were observed among the compounds of PCBs and OCPs, suggesting their similar sources and kinetic behaviors. BDE 47 had significant correlations with PCBs and OCPs, whereas BDE 209 was not correlated with any of the contaminants due to different exposure sources. The concentrations of p,p'-DDE, ß-HCH, and trans-nonaCHL between paired maternal blood-meconium and cord blood-meconium showed significant correlations, while PCBs and PBDEs were not significantly correlated in the paired samples. Maternal age and gestational age were demographic parameters affecting POP levels in meconium. Multiple regression analysis showed that the levels of several OCPs in cord and maternal serum were contributing factors governing the levels of these contaminants in meconium. Our results indicate that meconium can be utilized as a human matrix for prenatal exposure to several OCPs.

Infant exposure to polybrominated diphenyl ethers (PBDEs) via consumption of homemade baby food in Korea.

Limited data are available on the residue levels of polybrominated diphenyl ethers (PBDEs) in baby food. In this study, 24 PBDE congeners were determined in 147 homemade baby food samples collected from 97 households for 6-, 9-, 12-, 15-, and from 24 to 27-month-old infant groups during the period of 2012-2013. The concentrations of total PBDEs (ΣPBDE) ranged from 24.5 to 6000 (mean: 263) pg/g fresh weight, higher than those found in commercial formulae from the United States. The predominant congeners were BDEs 209 and 47, accounting for 92% of the ΣPBDE concentrations, reflected by high deca-BDE consumption in Korea. The residue levels and detection rates of BDE 47 in the baby food samples showed a gradual increasing trend with an increase in infant ages, due to changes in the food ingredients from hypoallergenic to greasy. The daily intakes of BDEs 47 and 209 via baby food consumption ranged from 0.04 to 0.58, 0.80 to 20.3, and 1.06 to 22.3 ng/kg body weight/day for 6-, 9-, 12-, 15-, and 24-27-month-old infant groups, respectively; these intakes were lower than the oral reference doses proposed by the US EPA. Together with three exposure sources, baby food, breast milk and dust ingestion for 6-month-old infants, the daily intake of ΣPBDE was 25.5 ng/kg body weight/day, which was similar to the intake via baby food consumption only for over 24-month-old infants in our study. This indicates that baby food is an important exposure pathway of PBDEs for over 24-month-old infants. This is the first study regarding the occurrence and exposure assessment of PBDEs via homemade baby food.

High-risk human papillomavirus infection is associated with premature rupture of membranes.

BACKGROUND: Human papillomavirus (HPV) is known to be more prevalent in spontaneous abortions than in elective terminations of pregnancy. More recently, placental infection with HPV was shown to be associated with spontaneous preterm delivery. However, no study has evaluated the prevalence of HPV infection in pregnant Korean females and its association with adverse pregnancy outcomes. METHODS: We conducted a cross-sectional study of 311 females who gave birth at Korea University Medical Center. Our sample included 45 preterm deliveries, 50 cases of premature rupture of the membranes (PROM), 21 preeclampsia cases, and 8 gestational diabetes mellitus (GDM) patients. We used the Hybrid Capture II system to detect high-risk (HR)-HPV infection at six weeks postpartum. RESULTS: The prevalence of HR-HPV infection was 14.1%. Women with HR-HPV infection had a higher incidence of PROM than those without HR-HPV. HR-HPV infection was associated with an increased risk of PROM (OR, 2.380; 95% CI, 1.103-5.134). The prevalence of preterm delivery, preeclampsia, or GDM was not different between the two groups. CONCLUSIONS: We observed a high prevalence of HR-HPV infection in pregnant women. Moreover, HR-HPV infection was associated with a risk of PROM at term. Further studies are needed to evaluate mechanisms by which HR-HPV infection induces PROM.

2-methoxyoestradiol levels and placental catechol-O-methyltransferase expression in patients with late-onset preeclampsia.

PURPOSE: Deficiencies in placental catechol-O-methyltransferase (COMT) and circulating 2-methoxyoestradiol (2-ME) have been shown to be related to early onset preeclampsia. The aim of this study was to investigate levels of 2-ME in the serum and urine of patients with late-onset preeclampsia and to compare those levels to those of normal pregnant women. In addition, we examined placental COMT expression in both groups. METHODS: Fifteen patients with preeclampsia and 15 normal pregnant women were enrolled. 2-ME levels were evaluated by ELISA and placental COMT expression was examined by Western blot analysis. RESULTS: 2-ME levels in serum [median 181.1 pg/mL, interquartile range (IQR) 119.6-244.3 vs. 61.2 pg/mL, IQR 12.0-133.7, respectively, p = 0.004] and urine (median 143.3 pg/mL, IQR 35.0-328.2 vs. 0.5 pg/mL, IQR 0.4-4.6, respectively, p < 0.001) were significantly increased in patients with late-onset preeclampsia compared to those in normal pregnant women at term. There was no significant difference in placental COMT expression between the two groups. CONCLUSION: Increased levels of 2-ME in patients with late-onset preeclampsia might be a product of a compensatory mechanism in patients with late-onset preeclampsia.

Small RNA sequencing of small extracellular vesicles secreted by umbilical cord mesenchymal stem cells following replicative senescence.

BACKGROUND: Umbilical cord mesenchymal stem cells (UCMSC) are subsets of multipotent stem cells involved in immune modulation, tissue regeneration, and antimicrobial defense. Cellular senescence is associated with the onset of aging-related diseases and small extracellular vesicles (sEVs) are important mediators of senescence and aging. OBJECTIVE: However, little is known about the role and function of microRNAs (miRNAs) carried by UCMSC-derived sEVs. To analyze the expression profiles of miRNAs secreted by senescent UCMSC, small RNA sequencing of the miRNAs within the sEVs was performed in this study. METHODS: UCMSC cultures underwent serial passaging beyond passage number 20 to achieve replicative senescence, which was confirmed by various methods, including increased senescence-associated ß-gal staining and cytokine secretion levels. sEVs derived from non-senescent and senescent UCMSC were isolated and characterized by nanoparticle tracking analysis, transmission electron microscopy, and immunoblot analysis. RESULTS: Small RNA sequencing of the miRNAs within the sEVs revealed senescence-associated differences in the miRNA composition, as shown by the upregulation of miR-122-5p and miR-146a-5p, and downregulation of miR-125b-5p and miR-29-3p. In addition, total RNA sequencing analysis showed that PENK, ITGA8, and TSIX were upregulated, whereas AKR1B10, UNC13D, and IL21R were downregulated by replicative senescence in UCMSC. In sEVs, upregulated genes were linked to downregulated miRNAs, and vice versa. In the gene-concept network analysis, five gynecologic terms were retrieved. CONCLUSIONS: The study provides an insight into the cellular characteristics of UCMSC following replicative senescence and emphasizes the importance of monitoring passage numbers of UCMSC for further therapeutic use.

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 [...].

COVID-19 and vaccination during pregnancy: a systematic analysis using Korea National Health Insurance claims data.

OBJECTIVE: This study systematically analyzed coronavirus disease 2019 (COVID-19) and vaccination details during pregnancy by using the national health insurance claims data. METHODS: Population-based retrospective cohort data of 12,399,065 women aged 15-49 years were obtained from the Korea National Health Insurance Service claims database between 2019 and 2021. Univariate analysis was performed to compare the obstetric outcomes of pregnant women (ICD-10 O00-O94) and their newborns (ICD-10 P00-P96) with and without COVID-19. Univariate analysis was also performed to compare the age and obstetric outcomes of pregnant women receiving different types of vaccines. RESULTS: The percentage of pregnant women with COVID-19 during pregnancy was 0.11%. Some obstetric outcomes of pregnant women with COVID-19, including the rates of preterm birth or cesarean delivery, were significantly better than those of pregnant women without COVID-19. The rate of miscarriage was higher in pregnant women with COVID-19 than without COVID-19. However, the outcomes of newborns of women with and without COVID-19 were not significantly different. Regarding vaccination type, obstetric outcomes of pregnant women appeared to be worse with the viral vector vaccine than with the mRNA vaccine. CONCLUSION: To the best of our knowledge, this is the first study to systematically analyze COVID-19 and vaccination details during pregnancy using the national health insurance claims data in Korea. The obstetric outcomes in pregnant women with and without COVID-19 and their newborns were similar.

Hourly fetal urine production rate in isolated oligohydramnios at term.

OBJECTIVE: The aim of this study was to evaluate the hourly fetal urine production rate (HFUPR) via three-dimensional ultrasonography in women with isolated oligohydramnios and compare with normal pregnant women at term. MATERIALS AND METHODS: This was a prospective observational cohort study of 112 women from 34 to 40 6/7 weeks' gestation. They were classified into three groups according to the amniotic fluid index (AFI) and ultrasonographic estimated fetal weight (EFW) as isolated oligohydramnios (defined as AFI below 5% and appropriate EFW corresponding to gestational age) (n = 34) and IUGR (defined as EFW below 5% corresponding to gestational age irrespective amniotic fluid) (n = 17), and normal pregnancy (n = 61). HFUPR was measured using three-dimensional virtual organ computer-aided analysis. Adverse perinatal outcomes in all participants were examined. RESULTS: There was no significant difference in HFUPR between patients with isolated oligohydramnios and women with normal pregnancies (median, 40.0 mL/h [interquartile range [IQR] 31.0-66.5] vs. 48.6 [31.5-81.2], p = 0.224). HFUPR was significantly decreased in the IUGR group (13.8 mL/h [IQR 10.1-24.8]), compared to the normal pregnancy group (p<0.001) and the isolated oligohydramnios group (p<0.001). HFUPR was significantly decreased in neonates with adverse perinatal outcomes compared to the control (24.7 mL/h [IQR 13.4-47.4] vs. 43.6 [29.8-79.0], p = 0.016). CONCLUSION: HFUPR was not decreased in patients with isolated oligohydramnios but was decreased in patients with IUGR when compared to normal controls at term.

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.

Risk of Early Childhood Obesity in Offspring of Women with Preeclampsia: A Population-Based Study.

Preeclampsia (PE) is a major disease of pregnancy, with various short- or long-term complications for both the mother and offspring. We focused on the body mass index (BMI) of offspring and compared the incidence of obesity during early childhood between PE- and non-PE-affected pregnancies. Women with singleton births (n = 1,697,432) were identified from the Korea National Health Insurance database. The outcomes of offspring at 30-80 months of age were analyzed. The effects of PE on BMI and the incidence of obesity in the offspring were compared. The incidence of low birth weight (LBW) offspring was higher in the PE group (n = 29,710) than that in the non-PE group (n = 1,533,916) (24.70% vs. 3.33%, p < 0.01). However, BMI was significantly higher in the PE-affected offspring than that in non-PE-affected offspring. After adjusting for various factors, the risk of obesity was higher in the PE-affected offspring (odds ratio = 1.34, 95% confidence interval = 1.30-1.38). The BMI and incidence of obesity were higher during early childhood in the PE-affected offspring, even though the proportion of LBW was higher. These results may support the basic hypotheses for the occurrence of various cardiovascular and metabolic complications in PE-affected offspring. In addition, early-age incidence of obesity could influence PE management and child consultation in clinical applications.

Use of the shock index to predict maternal outcomes in women referred for postpartum hemorrhage.

OBJECTIVE: To evaluate the clinical significance of various vital signs in women referred for postpartum hemorrhage (PPH). METHODS: This retrospective study included patients with primary PPH who were referred to Korea University Medical Center, Ansan, between January 1, 2004, and December 31, 2016. We analyzed data for systolic and diastolic blood pressure, heart rate, and shock index (heart rate divided by systolic blood pressure) at time of arrival. Significant morbidity, such as massive transfusion, invasive procedures, and admission to the intensive care unit were reviewed. We used the area under the receiver operating characteristic curve (AUROC) for each vital sign to predict adverse maternal  outcomes. Sensitivity, specificity, and negative and positive predictive values were assessed. RESULTS: 118 women with PPH were identified. The shock index had the highest AUROC to predict massive transfusion (0.815, 95% confidence interval [CI] 0.727-0.883). A shock index greater than 0.9 had 93.8% (95% CI 69.8-99.8) sensitivity and 51.2% (35.1-67.1) specificity for prediction of massive transfusion, and 93.6% (78.6-99.2) sensitivity and 31.0% (15.3-50.8) specificity for prediction of invasive procedures. CONCLUSION: The shock index has significant ability to predict adverse outcomes of PPH compared with other initial vital signs when patients are referred.

Bisphenol A in infant urine and baby-food samples among 9- to 15-month-olds.

Diet is the predominant source of bisphenol A (BPA) intake, but limited data are available on BPA levels in the diet of younger infants. This study investigated BPA levels in baby-food and urine samples collected from young infants (under 2 years old). Samples of homemade baby food (n = 210) and urine (n = 187) were collected at 9, 12, and 15 months after birth from a panel of Korean infants (n = 173). BPA levels in urine and food were measured using HPLC-MS/MS and GC-MS, respectively. BPA was above the limit of detection (LOD) in 85.5-85.7% of the urine samples and 32.5-76.3% of the baby-food samples. The median levels of BPA were 0.45 ng/g wet weight (IQR: not detectable to 5.16 ng/g wet weight) in homemade baby food, 0.93 µg/L (IQR:

Association between maternal exposure to major phthalates, heavy metals, and persistent organic pollutants, and the neurodevelopmental performances of their children at 1 to 2years of age- CHECK cohort study.

Exposure of the developing fetus and infants to toxic substances can cause serious lifelong health consequences. Several chemicals have been associated with adverse neurodevelopmental disorders in the early life stages of humans. However, most epidemiological studies have focused on a limited number of chemicals, and hence may exclude important chemicals from consideration or result in conclusions built on associations by chance. In the present study, we investigated the chemical exposure profile of the women, and associated these with the early neurodevelopmental performance of their offspring at 13-24months of age. The chemicals assessed include four phthalates, bisphenol A, three heavy metals, 19 polychlorinated biphenyls (PCBs), 19 organochlorine pesticides, and 19 polybrominated diphenyl ethers, which were measured from urine, whole blood, serum, and/or breastmilk of the pregnant or lactating women. For neurodevelopmental performance, the Bayley Scales of Infant Development-II (BSID-II), Social Maturity Scale (SMS), and Child Behavior Checklist (CBCL) were measured from a total of 140 toddlers. Among the measured chemicals, monoethyl phthalate (MEP) in maternal urine was significantly associated with early mental, psychomotor, and social development. In addition, breast milk di-ethylhexyl phthalate (DEHP) metabolite and blood lead concentrations were inversely associated with mental and psychomotor development indices, respectively. Maternal blood PCB153, heavy metals, and urinary MEP levels were also higher among the children with behavioral problems, as indicated by the CBCL range. Taken together, maternal exposure to several EDCs such as PCBs and DEHP was associated with adverse neurodevelopmental performances among the children aged 1-2years. Confirmation of these association in larger populations, as well as longer-term consequences of such exposure warrant further investigation.

Uterine rupture in pregnancies following myomectomy: A multicenter case series.

OBJECTIVE: The purpose of this case series was to retrospectively examine records of cases with uterine rupture in pregnancies following myomectomy and to describe the clinical features and pregnancy outcomes. METHODS: This study was conducted as a multicenter case series. The patient databases at 7 tertiary hospitals were queried. Records of patients with a diagnosis of uterine rupture in the pregnancy following myomectomy between January 2012 and December 2014 were retrospectively collected. The uterine rupture cases enrolled in this study were defined as follows: through-and-through uterine rupture or tear of the uterine muscle and serosa, occurrence from 24+0 to 41+6 weeks' gestation, singleton pregnancy, and previous laparoscopic myomectomy (LSM) or laparotomic myomectomy (LTM) status. RESULTS: Fourteen pregnant women experienced uterine rupture during their pregnancy after LSM or LTM. Preterm delivery of less than 34 weeks' gestation occurred in 5 cases, while intrauterine fetal death occurred in 3, and 3 cases had fetal distress. Of the 14 uterine rupture cases, none occurred during labor. All mothers survived and had no sequelae, unlike the perinatal outcomes, although they were receiving blood transfusion or treatment for uterine artery embolization because of uterine atony or massive hemorrhage. CONCLUSION: In women of childbearing age who are scheduled to undergo LTM or LSM, the potential risk of uterine rupture on subsequent pregnancy should be explained before surgery. Pregnancy in women after myomectomy should be carefully observed, and they should be adequately counseled during this period.

Association of diethylhexyl phthalate with obesity-related markers and body mass change from birth to 3†months of age.

BACKGROUND: Several studies have suggested potential links of phthalates to obesity in children and adults. Limited evidence, however, has been available for the relations between diethylhexyl phthalate (DEHP) and obesity-related markers or body mass change in early life. METHODS: 128 healthy pregnant women were recruited and, after delivery, their newborns' first urine and umbilical cord blood samples were collected. We measured urinary levels of two DEHP metabolites, mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP). We also measured the levels of leptin, total cholesterol and triglyceride (TG) in cord serum, and used them along with weight, length, head circumference and ponderal index (PI, 100 g/cm(3)) at birth, as obesity-related markers, and estimated the relations between DEHP metabolites and obesity-related markers using generalised linear models. For the evaluation of body mass increase by early life DEHP exposure, body mass index (BMI) z-score change during 3 months after birth by DEHP metabolites in the first urine samples of the newborns were evaluated using logistic regression. RESULTS: DEHP exposure was associated with decrease of PI and increase of TG (PI, ß=-0.11, p=0.070 and TG, ß=0.14, p=0.027), especially for boys (PI, ß=-0.13, p=0.021; and TG, ß=0.19, p=0.025). Moreover, DEHP exposure was positively associated with body mass increase during 3 months after birth (change of BMI z-scores, OR=4.35, p=0.025). CONCLUSIONS: Our findings suggest that DEHP exposure may affect body mass change in early life through changes of obesity-related markers.

Concentrations of phthalate metabolites in breast milk in Korea: estimating exposure to phthalates and potential risks among breast-fed infants.

Phthalates have been associated with endocrine disruption and developmental effects in many experimental and epidemiological studies. Developing infants are among the most susceptible populations to endocrine disruption. However, limited information is available on phthalate exposure and its associated risks among breast-fed newborn infants. In the present study, breast milk samples were collected from 62 lactating mothers at 1 month post-partum from four cities of Korea in 2012 and were evaluated for six phthalate metabolites (mono-isobutyl phthalate (MiBP), mono-n-butyl phthalate (MnBP), mono(2-ethyl-hexyl) phthalate (MEHP), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP) and monoethyl phthalate (MEP)). MEP was detected in all breast milk samples, with a median concentration of 0.37 µg/L, and MiBP, MnBP and MEHP were detected in 79-89% of samples, with median concentrations of 1.10, 1.70, and 2.08 µg/L, respectively. However, MEHHP and MEOHP, the oxidized forms of di-ethyl-hexyl phthalate (DEHP), were detected in only one sample. For exposure assessment, the levels of phthalate diesters were estimated based on the parent:metabolite ratios in the breast milk that are reported elsewhere. For risk assessment, the endocrine-related toxicity of the monoester was assumed to be the same as that of its diester form. Median daily intake estimates of phthalates, including both monoester and diester forms, through breast milk consumption ranged between 0.91 and 6.52 µg/kg body weight (bw) for DEHP and between 0.38 and 1.43 µg/kg bw for di-n-butyl phthalate (DnBP). Based on the estimated daily intake, up to 8% of infants exceeded the reference dose of anti-androgenicity (RfD AA) for DEHP, and 6% of infants exceeded the tolerable daily intake (TDI) for DnBP. Breast milk MiBP and MnBP concentrations showed significant positive associations with maternal consumption of whipped cream or purified water. Considering vulnerability of young infants, efforts to mitigate phthalate exposure among lactating women are warranted.

Occurrence and exposure assessment of polychlorinated biphenyls and organochlorine pesticides from homemade baby food in Korea.

Data on the residue levels of persistent organic pollutants (POPs) in baby food samples are scarce. This is the first study to explore current contamination status and exposure assessment of organochlorines (OCs), including polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs), in baby food from Korea. In this study, the concentrations of OCs were determined in homemade baby food samples (n=100) collected from 6-, 9-, 12- and 15-month-old infant groups. The average concentrations of PCBs, dichloro-diphenyl-trichloroethanes (DDTs), hexachlorocyclohexanes (HCHs) and chlordanes (CHLs) in baby food samples were 37.5, 96.6, 26.0, and 13.2 pg/g fresh weight, respectively. The major compounds were CBs 28, 153, 52, and 33 for PCBs and p,p'-DDE, p,p'-DDT and ß-HCH for OCPs. The contribution of DDTs to the total OC concentrations increased from 30% (6-month-old infants) to 67% (15-month-old infants) with increasing infant age, while the concentrations of PCBs, HCHs and CHLs gradually decreased with increasing infant age, suggesting that highest priority for risk reduction of DDTs. The estimated daily intakes (EDIs) of OCs in Korean infants from baby food consumption were lower than the thresholds proposed by the United States Environmental Protection Agency and Health Canada, implying limited potential health risks. However, considering simultaneous exposure from baby food and breast milk consumption, chlordanes and heptachlor epoxide posed potential health risks. Considering the importance of early development and the vulnerability of infants, it is essential to perform systematic monitoring and management programs of OCs in baby food for risk reduction in Korean infants.