Published papers

Background: Progress in reducing the global low birthweight (LBW) has been insufficient. Although the focus has been on preventing preterm birth, evidence regarding LBW in term births is limited. Despite its low preterm birth prevalence, Japan has a higher LBW proportion than other developed countries. This study aimed to examine the prevalence of LBW in term singleton births and its associated factors using a national database. Methods: We retrospectively analyzed the data of neonates registered in the Japan Society of Obstetrics and Gynecology Successive Pregnancy Birth Registry System who were born 2013–2017. Exclusion criteria included stillbirths, delivery after 42 gestational weeks, and missing data. Logistic regression analyses were performed to investigate the maternal and perinatal factors associated with LBW in term singletons using the data of 715,414 singleton neonates. Results: The overall prevalence of LBW was 18.3%, and 35.7% of LBWs originated from singleton term pregnancies. Multiple logistic regression analyses indicated that both modifiable and non-modifiable factors were independently associated with LBW in term neonates. The modifiable maternal factors included pre-pregnancy underweight, inadequate gestational weight gain, and smoking during pregnancy, while the non-modifiable factors included younger maternal age, nulliparity, hypertensive disorders of pregnancy, cesarean section delivery, female offspring, and congenital anomalies. Conclusion: Using the Japanese pregnancy birth registry data, more than one-third of LBWs were found to originate from singleton term pregnancies. Both modifiable and non-modifiable factors were independently associated with LBW in term neonates. Prevention strategies on modifiable risk factor control will be effective in reducing LBW worldwide.

Objective: The authors aimed to investigate the prevalence of pregnancy and obstetric outcomes in patients who underwent radical trachelectomy (RT) for early-stage cervical cancer in the Kanto area, Japan. Method: A survey among 113 perinatal centers affiliated with the Kanto Society of Obstetrics and Gynecology was conducted to investigate their experience in managing pregnancies following RT, between 2010 and 2020. The association between preterm delivery (before 34 gestational weeks) and a midtrimester short cervix (<13 mm) was evaluated. Results: The authors retrospectively collected maternal and perinatal data from 13 hospitals. There were 135 pregnancies among 115 women following RT. Of the 135 pregnancies, 32 were miscarriages (<12 gestational weeks: n = 22; >12 gestational weeks: n = 10), and 103 were delivered after 22 gestational weeks. The incidences of preterm delivery before 28 and 34 gestational weeks were 8.7% and 30.1%, respectively. A midtrimester short residual cervix was associated with preterm delivery (P = 0.046). Conclusion: Since more than 100 pregnancies were recorded after RT in the Kanto area, many physicians had more opportunities to manage pregnancy after RT. Pregnancy following RT is associated with increased risk of preterm delivery, and midtrimester short residual cervix is a good predictor of preterm delivery.

Background: Strict glycemic control is important to prevent perinatal complications in patients with gestational diabetes mellitus (GDM). Patients often require insulin injection, and frequent hospital visits are necessary to adjust the dose of insulin, which is considered burdensome for pregnant patients. Telemedicine may reduce the burden of hospital visits, and previous studies have reported its safety in GDM patients. This study aimed to evaluate the efficacy of telemedicine in GDM patients, focusing on patient satisfaction and health economic indicators. Methods: This is a single-center, two-arm, randomized, open-label parallel-group study. Subjects will be selected from the patient population attending the Department of Endocrinology, Metabolism, and Nephrology, Keio University School of Medicine, Japan. Patients diagnosed with GDM by an oral glucose tolerance test (OGTT) by 29 weeks and 6 days of gestation who have undergone self-monitoring of blood glucose (SMBG) and insulin injection are eligible for inclusion. In the intervention group, telemedicine will be administered using the MeDaCa telemedicine system developed by the Medical Data Card, Inc., Tokyo, Japan. Subjects in the control group will be examined face-to-face every 2–3 weeks, as usual. We set health economic indicators and patient satisfaction as the primary endpoints, and will perform a cost-consequence analysis. Glycemic control indicators and perinatal outcomes will be evaluated as secondary endpoints. Conclusions: Eligible patients are currently being recruited. Recruitment will be completed when the expected number of patients are enrolled.

Late preterm (LP, born between 34 0/7 and 36 6/7 weeks of gestation) infants may experience several adverse outcomes, similar to those experienced by low birthweight (LBW, birthweight <2500 g) infants. However, while LP infants are often born with LBW, the association between LP and LBW remains unknown. This study aimed to investigate LBW rate and independent risk factors for LBW in LP singleton neonates. We retrospectively analyzed data of LP singleton neonates, born between 2013 and 2017, from the Japan Society of Obstetrics and Gynecology Successive Pregnancy Birth Registry System. The exclusion criteria included stillbirths and infants with missing data. Logistic regression analyses were performed to investigate maternal and perinatal factors associated with LBW in LP singletons. LBW was observed in 62.5% (n = 35,113) of 56,160 LP singleton births. In the multiple logistic regression analysis, LBW in LP neonates was independently associated with modifiable maternal factors, including pre-pregnancy underweight, inadequate gestational weight gain, and smoking during pregnancy, as well as non-modifiable factors, including younger maternal age, nulliparity, hypertensive disorder of pregnancy, preeclampsia, cesarean section delivery, and female offspring. According to the Japanese pregnancy birth registry data, more than half of LP neonates were LBW. We previously discussed the issue of LBW regarding infants with different backgrounds, as there are many different causes of LBW. Several risk factors should be subdivided and considered for the risk of LP and LBW.

To evaluate perinatal outcomes and risk factors for large for gestational age (LGA; birth weight over 90 percentile) in gestational diabetes diagnosed before 24 gestational weeks and treated with diet therapy alone until delivery (Diet Early gestational diabetes mellitus (Diet Early GDM)), we assessed the maternal characteristics and perinatal outcomes of patients with early GDM (n = 309) and normal glucose tolerance (NGT; n = 309) at Keio University Hospital. The gestational weight gain (GWG) expected at 40 weeks was significantly lower in the Diet Early GDM group than in the NGT group. The Diet Early GDM group exhibited a significantly lower incidence of low birth weight (<2500 g) and higher Apgar score at 5 min than the NGT group. Multiple logistic regression analysis revealed that the pre-pregnancy body mass index and GWG expected at 40 weeks were significantly associated with LGA for Diet Early GDM. No differences were observed in random plasma glucose levels in the first trimester, 75 g oral glucose tolerance test values, and initial increase or subsequent decrease between the two groups. Dietary early GDM did not exhibit a worse prognosis than NGT. To prevent LGA, it might be important to control maternal body weight not only during pregnancy but also before conception.

Aim: Some concerns exist that diagnosis of gestational diabetes mellitus (GDM) may be missed when the simplified diagnostic criteria of the Japanese Society of Diabetes and Pregnancy (JSDP) for GDM (published during the COVID-19 pandemic) are used. Moreover, limited data is available regarding how widespread these diagnostic criteria are used when managing GDM during the COVID-19 pandemic. Therefore, this study aimed to determine how GDM diagnosis has changed during the COVID-19 pandemic in Japan. Methods: The changes in GDM diagnosis during the COVID-19 pandemic were investigated using an online questionnaire to 2159 obstetric facilities in Japan. The questionnaire collected data on facility type, awareness of Japanese GDM diagnostic strategies, modifications to diagnostic methods for early and late GDM, and opinions on GDM management, with the pandemic divided into seven periods. Results: We received responses from 593 facilities (27%). Approximately 90% of the facilities did not change their diagnostic process for early GDM or late GDM (occurring after 24 weeks gestation). However, during the COVID-19 pandemic, 19 facilities discontinued the use of 75-g oral glucose tolerance tests before 24 weeks of gestation, and 17 facilities discontinued it after 24 weeks of gestation, instead using the aforementioned Japanese GDM diagnostic strategy. Conclusions: Although a limited number of facilities modified their diagnostic method in response to the COVID-19 pandemic, this study demonstrated that those that adjusted their diagnostic method primarily used the Japanese COVID-19 GDM strategy by the JSDP.

Background: Maternal obesity influences birth weight and newborn adiposity. Fetal fractional limb volume has recently been introduced as a useful parameter for the proxy of fetal adiposity. However, the association between maternal adiposity and the growth of fetal fractional limb volume has not been examined. Aims: To investigate the association of maternal pre-pregnancy BMI with the growth of fetal fractional limb volume. Study design: Prospective cohort study. Subjects: Women with singleton uncomplicated pregnancies enrolled between July 2017 and June 2020. Outcome measures: Fetal fractional limb volume was assessed between 20 and 40 weeks' gestation, measured as cylindrical limb volume based on 50 % of the total diaphysis length. The measured fractional limb volume at each gestational week were converted to z-scores based on a previous report. The association between pre-pregnancy BMI and fetal fractional limb volume was examined. Maternal age, parity, gestational weight gain and fetal sex were considered as potential confounding variables. Results: Ultrasound scans of 455 fractional arm volume and thigh volume were obtained. Fractional limb volume increased linearly until the second trimester of gestation, then increased exponentially in the third trimester. Maternal pre-pregnancy BMI was significantly correlated with z-scores of fractional arm volume and thigh volume across gestation. The post-hoc analysis showed the association between pre-pregnancy BMI and fractional arm volume was significant especially between 34 and 40 weeks. Conclusions: Maternal obesity influences the growth pattern of fetal fractional limb volume. Fractional arm volume may potentially provide a useful surrogate marker of fetal nutritional status in late gestation.

妊娠糖尿病(GDM)の新診断基準は周産期合併症のリスクをもとに作成されたものであり、産後早期糖代謝異常の発症リスクに関する知見は少ない。そこで本研究では基準改定後の当院における周産期データをもとに、GDM既往女性の産後早期糖代謝異常の発症頻度およびその予測指標を検討した。対象は2011年以降に当院で周産期管理を行った新基準GDMのうち産後4〜6ヵ月に75g経口ブドウ糖負荷試験(OGTT)を受けた女性47名(GDM診断時OGTT 1点陽性33例;2点陽性11例;3点陽性3例)である。日本糖尿病学会診断基準をもとに産後早期糖代謝異常の有無を判定したところ、糖代謝正常型29名、糖代謝異常型18名(境界型14名;糖尿病型4名)であった。GDM診断時OGTT陽性ポイント数別に検討すると、OGTT 1点、2点および3点陽性例のおのおの33%、45%、67%において産後早期に糖代謝異常型を認めた。またreceiver-operating characteristic(ROC)解析を用いてGDM診断時の血糖・metabolic phenotypeによる産後早期糖代謝異常の発症予測能を検討した。OGTT 1時間値、2時間値およびoral disposition index(DI)による予測では、ROC曲線下面積はそれぞれ0.74、0.70および0.74であった。ROC解析に基づきOGTT 1時間値、2時間値およびOral DIのカットオフ値をそれぞれ160mg/dl、143mg/dl、1.72とした場合、産後早期糖代謝異常の発症予測に関する感度は94%、89%および72%、特異度は48%、51%および71%となった。以上より、OGTT1時間値および2時間値およびOral DIが産後早期糖代謝異常発症予測に有用である可能性が示唆された。(著者抄録)

Objective: The opportunities for sequencing-based methylome analysis of clinical samples are increasing. To reduce its cost and the amount of genomic DNA required for library preparation, we aimed to establish a capture methyl-seq protocol, which adopts pre-pooling of multiple libraries before hybridization capture and TET2/APOBEC-mediated conversion of unmethylated cytosine to thymine. Results: We compared a publicly available dataset generated by the standard Agilent protocol of SureSelect XT Human Methyl-Seq Kit and our dataset obtained by our modified protocol, EMCap, that adopted sample pre-pooling and enzymatic conversion. We confirmed that the quality of DNA methylation data was comparable between the two datasets. As our protocol, EMCap, is more cost-effective and reduces the amount of input genomic DNA, it would serve as a better choice for clinical methylome sequencing.

© 2017 Wiley Periodicals, Inc. The cover image, by Satoru Ikenoue et al., is based on the Clinical Report Discordant fetal phenotype of hypophosphatasia in two siblings, DOI: 10.1002/ajmg.a.38531.

© 2017 Wiley Periodicals, Inc. Hypophosphatasia (HPP) is an autosomal recessive metabolic disorder with impaired bone mineralization due to mutations in the ALPL gene. The genotype-phenotype correlation of this disorder has been widely described. Here, we present two affected siblings, whose fetal phenotypes were discordant. A 31-year-old Japanese woman, G0P0, was referred to our institution because of fetal micromelia. After obstetric counseling, the pregnancy was terminated at 21 weeks’ gestation. Post-mortem radiographs demonstrated severely defective mineralization of the skeleton. The calvarial, spinal, and tubular bones were mostly missing. Only the occipital bones, mandible, clavicles, ribs, one thoracic vertebra, ilia, and tibia were relatively well ossified. The radiological findings suggested lethal HPP. Genetic testing for genomic DNA extracted from the umbilical cord identified compound heterozygous mutations in the ALPL gene (c.532T>C, p.Y178H; c.1559delT, p.Leu520Argfs*86). c.532T>C was a novel variant showing no residual activity of the protein by the functional analysis. The parents were heterozygous carriers. In the next pregnancy, biometric values on fetal ultrasonography at 20 and 26 weeks’ gestation were normal. At 34 weeks, however, a small chest and shortening of distal long bones came to attention. The neonate delivered at 41 weeks showed serum ALP of <5U/L. Radiological examination showed only mild thoracic hypoplasia and metaphyseal mineralization defects of the long bones. ALP replacement therapy was introduced shortly after birth, and the neonate was discharged at day 22 without respiratory distress. Awareness of discordant fetal phenotypes in siblings with HPP precludes a diagnostic error, and enables early medical intervention to mildly affected neonates.

© 2018 The Authors. Journal of Diabetes Investigation published by Asian Association for the Study of Diabetes (AASD) and John Wiley & Sons Australia, Ltd Aims/Introduction: Risk factors of type 2 diabetes mellitus in Japanese women with recent gestational diabetes mellitus are unknown. The objective of the present study was to investigate the clinical and genetic characteristics associated with postpartum abnormal glucose tolerance in Japanese women with gestational diabetes mellitus. Materials and Methods: A total of 213 Japanese women with recent gestational diabetes mellitus who underwent a postpartum 2-h oral glucose tolerance test were investigated. The association between antepartum clinical characteristics and postpartum abnormal glucose tolerance (diabetes or prediabetes based on the Japan Diabetes Society criteria) was examined. Frequencies of 45 known type 2 diabetes mellitus-associated genetic variants were also compared between women with and without postpartum abnormal glucose tolerance. Results: A total of 59 women showed postpartum abnormal glucose tolerance (prediabetes, n = 51; diabetes, n = 8). Plasma glucose levels at 1 or 2 h, the insulinogenic index and the insulin secretion-sensitivity index-2 of the antepartum oral glucose tolerance test were independent of postpartum abnormal glucose tolerance risk factors (P = 0.006, P = 0.00002, P = 0.01 and P = 0.006, respectively). Four genetic variants (rs266729 [ADIPOQ], rs6017317 [HNF4A], rs5215 [KCNJ11] and rs7177055 [HMG20A]) showed a nominally significant association with postpartum abnormal glucose tolerance (P < 0.05, respectively). Among these, three were related to insulin secretion. Postpartum abnormal glucose tolerance risk significantly increased with increasing risk-allele number (P = 0.0005; odds ratio 1.91). Conclusions: Clinical features and genetic variants related to impaired insulin secretion are risk factors of postpartum abnormal glucose tolerance in Japanese women with recent gestational diabetes mellitus.

Introduction: The average birth weight in Japan has gradually decreased and the number of low birth weight infant has increased over the last 30 years. Japanese pregnant women are characterized with lower prevalence of obesity than those in other developed countries, and maternal underweight before pregnancy is independently associated with low birth weight. However, the association between maternal inadequate gestational weight gain (GWG) and the risk of small for gestational age (SGA) in Japanese uncomplicated pregnant women has not been fully understood. This study aimed to examine the effect of maternal inadequate GWG on the risk of SGA in Japanese uncomplicated pregnancies. Methods: We retrospectively analyzed uncomplicated Japanese singleton pregnancies that delivered at term gestation in our institution from 2006 to 2016. The association between GWG and birth weight was analyzed by multiple linear regression. Potential confounding factors included maternal age, parity, prepregnancy BMI, and neonatal sex. The association between inadequate GWG and SGA was also examined by logistic regression. Results: A total of 3837 mother–neonate dyads were analyzed. Maternal GWG was 10.1 ± 3.7 kg (mean ± SD), and 2529 (66%) had inadequate GWG. After adjusting for confounding factors, GWG significantly correlated with birth weight (standardized β = 0.199, p <.001). Inadequate GWG increased the risk of delivering SGA neonate (adjusted odds ratio (aOR) = 1.97 [1.45–2.68], p <.001). This association was particularly pronounced in underweight (aOR = 2.95 [1.38–6.29], p =.005) and normal weight mothers (aOR = 1.79 [1.27–2.52], p =.001), and not in overweight/obese mothers (p =.115). Conclusion: Maternal GWG is associated with birth weight in Japanese women with uncomplicated singleton pregnancies. Inadequate GWG is an important risk factor of SGA, particularly in non-obese women. The present finding would potentially provide further evidence that promoting adequate gestational weight gain in Japanese underweight and normal weight mothers would reduce SGA, as well as metabolic dysfunction in later life.