Gestational bodyweight gain among underweight Japanese women related to small-for-gestational-age birth

Association Between Body Image Before and During Pregnancy and Gestational Weight Gain in Japanese Women: A Prospective Cohort Study

OBJECTIVES

More than half of women do not achieve appropriate gestational weight gain. Maternal body image may be an important factor associated with gestational weight gain. However, this association has not been thoroughly evaluated. We aimed to elucidate whether body image parameters before and during pregnancy are associated with gestational weight gain in Japanese women.

METHODS

This prospective cohort study was conducted at a hospital in Osaka, Japan from March 2020 to March 2021. We recruited women with singleton pregnancies in their second and third trimesters. Body image was assessed using the Pregnancy and Weight Gain Attitude Scale and additional questions. Gestational weight gain was classified as insufficient, appropriate, or excessive based on recommended ranges in Japan. One-way analysis of variance, chi-square tests, and multinomial logistic regression analyses were performed to identify factors associated with insufficient or excessive weight gain.

RESULTS

Of 266 enrolled women, 47 had insufficient weight gain and 100 had excessive weight gain during pregnancy. Risk factors for excessive gestational weight gain included a history of dietary restriction before pregnancy, negative attitudes toward gestational weight gain, and perception of body shape as fat and body shape dissatisfaction during pregnancy. Perception of body shape as thin during pregnancy was identified as a risk factor for insufficient gestational weight gain.

CONCLUSIONS

Body image before and during pregnancy may be an important factor in preventing insufficient or excessive gestational weight gain in Japanese women. Healthcare professionals should consider body image when providing health guidance on weight management to pregnant women.

Characteristics of women who dropped out from pregnancy register in Okinawa, Japan: Findings from a retrospective cohort study

AIM

There is little evidence regarding women who cannot register live births after pregnancy. We aimed to clarify the difference in baseline characteristics between women who registered live births and those who did not (i.e., dropout).

METHODS

We assessed the birth cohort data of 1976 Japanese women who registered their pregnancies between July 2013 and March 2014 in Naha and Urasoe City, Okinawa, Japan. The database consisted of anthropometric data, reproductive history, sociodemographic characteristics, and dietary intake. We estimated the prevalence ratio to examine the associations of baseline characteristics with dropout by multivariable-adjusted Poisson regression with robust standard error estimation.

RESULTS

We identified 272 dropouts (13.8%) in the pregnancy registry. About 15% of women reported experience of alcohol drinking preceding 1 month of pregnancy registration. Most participants' vitamin B1 (92.1%) and folate (74.7%) consumption was inadequate considering the dietary reference intake for Japanese pregnant women, but it was not associated with a high prevalence of dropout. The prevalence of dropout was significantly higher in teenagers (prevalence ratio [PR] = 2.06, 95% confidence interval [CI] 1.38-3.07) and early 20s (PR = 1.42, 95% CI 1.04-1.93) than in women in late 20s. In addition, alcohol consumption was potentially associated with a high prevalence of dropout (adjusted prevalence ratio [aPR] = 1.31, 95% CI 0.99-1.73). Participants who experienced one or more live births (aPR = 0.43, 95% CI 0.28-0.66) were less likely to dropout.

CONCLUSION

We found that the potential risk factors for dropout from pregnancy registration were young maternal age, no childbirth experience, and alcohol consumption.

Birth weight reference for Japanese twins and risk factors for infant mortality: A population-based study

There is no standard birth weight curve for twins in Japan other than a prototype curve based on 1988–1991. Twins have a high perinatal mortality rate than singletons; therefore, we developed a new standard curve for twin birth weight using data from the 1995–2016 Vital Statistics and compared it with previous reports. We used 469,064 cases for analysis, excluding stillbirths and cases with missing values, and created a standard curve using LMS (statistical methods to vary the distribution by using skewness, median, and coefficient of variation) method. In comparison with previous reports, the mean birth weight decreased by 100–200 g. The groups with the lowest neonatal death rates (NDRs) and infant death rates (IDRs) were those with a birth weight of 1,500–2,499 g (NDR: 0.3%, IDR: 0.6%) and those born at 34–36 weeks (NDR: 0.2%, IDR: 0.4%). Compared to these, the IDR was significantly higher in the 2,500–3,999 g group and the 37–39 weeks group (incidence rate ratio (IRR): 1.1 in the 2,500–3,999 g group, IRR: 1.3 in the 37w0d–39w6d group). In particular, the risks of neonatal mortality and infant mortality were higher in infants born at a birth weight above 3,500 g. Infants born at a birth weight above 3,500 g may include recipients of twin-to-twin transfusion syndrome. The most common causes of infant mortality are accidental death and sudden infant death syndrome (SIDS). We considered the possibility that infants treated as healthy newborns and whose mothers were discharged from the hospital without adequate twin care guidance may be more likely to experience unintentional accidents and SIDS at home. The present study suggested that creating a new twin birth weight standard curve and guidance on managing twins at home for full-term and normal birth weight infants may lead to a reduction in infant deaths.

Effect of maternal smoking during pregnancy on gestational weight gain and birthweight: A stratified analysis by pregestational weight status

INTRODUCTION

METHODS

RESULTS

CONCLUSIONS

Maternal Serum Albumin Redox State Is Associated with Infant Birth Weight in Japanese Pregnant Women

Background: Plasma albumin (ALB) reflects protein nutritional status in rats, but it is not clear whether it is associated with dietary protein insufficiency in pregnant women and/or their risk of low birth weight delivery. This study aimed to investigate whether maternal serum ALB redox state reflects maternal protein nutritional status and/or is associated with infant birth weights. Methods: The relationship between the serum reduced ALB ratio and infant birth weight was examined in an observational study of 229 Japanese pregnant women. A rat model simulating fetal growth restriction, induced by protein-energy restriction, was used to elucidate the relationship between maternal nutritional status, maternal serum ALB redox state, and birth weight of the offspring. Results: In the human study, serum reduced ALB ratio in the third trimester was significantly and positively correlated with infant birth weight. In the rat study, serum reduced ALB ratio and birth weight in the litter decreased as the degree of protein-energy restriction intensified, and a significant and positive correlation was observed between them in late pregnancy. Conclusions: Maternal serum reduced ALB ratio in the third trimester is positively associated with infant birth weight in Japanese pregnant women, which would be mediated by maternal protein nutritional status.

Hypertensive Disorders during Pregnancy (HDP), Maternal Characteristics, and Birth Outcomes among Japanese Women: A Hokkaido Study

Hypertension during pregnancy causes a greater risk of adverse birth outcomes worldwide; however, formal evidence of hypertensive disorders during pregnancy (HDP) in Japan is limited. We aimed to understand the association between maternal characteristics, HDP, and birth outcomes. In total, 18,833 mother-infant pairs were enrolled in the Hokkaido study on environment and children’s health, Japan, from 2002 to 2013. Medical records were used to identify hypertensive disorders and birth outcomes, namely, small for gestational age (SGA), SGA at full term (term-SGA), preterm birth (PTB), and low birth weight (LBW). The prevalence of HDP was 1.9%. Similarly, the prevalence of SGA, term-SGA, PTB, and LBW were 7.1%, 6.3%, 7.4%, and 10.3%, respectively. The mothers with HDP had increased odds of giving birth to babies with SGA (2.13; 95% Confidence Interval (CI): 1.57, 2.88), PTB (3.48; 95%CI: 2.68, 4.50), LBW (3.57; 95%CI: 2.83, 4.51) than normotensive pregnancy. Elderly pregnancy, low and high body mass index, active and passive smoking exposure, and alcohol consumption were risk factors for different birth outcomes. Therefore, it is crucial for women of reproductive age and their families to be made aware of these risk factors through physician visits, health education, and various community-based health interventions.

Association between infertility treatment and intrauterine growth: a multilevel analysis in a retrospective cohort study

OBJECTIVES

This study aimed to identify intrauterine growth differences according to infertility treatment compared with spontaneous conception and to describe intrauterine growth trajectories.

DESIGN

Retrospective cohort study.

SETTING

A single primary and tertiary medical centre in Japan.

PARTICIPANTS

This study included singleton pregnant women with prenatal check-ups and delivery at the University of Yamanashi Hospital between 1 July 2012 and 30 September 2017. Patients were divided into four groups: spontaneous conception, infertility treatment without assisted reproductive technology (ART), fresh-embryo transfer and frozen embryo transfer (FET).

INTERVENTIONS

Differences in intrauterine growth according to the infertility treatment, including ART, and birth weight were evaluated. Multilevel analysis was employed to evaluate intrauterine growth trajectories stratified by the sex of the offspring.

PRIMARY OUTCOME MEASURE

Estimated fetal weight (EFW) assessed by ultrasound examination.

RESULTS

We assessed data from 37 239 prenatal examination results from 2377 pregnant women (spontaneous conception, n=1764; infertility treatment without ART, n=171; fresh-embryo transfer, n=112; and FET, n=330) in the final analysis. Multilevel analysis was adjusted for gestation duration, gestation period, parity, hypertensive disorders of pregnancy, type of infertility treatment, maternal age, smoking status, placenta previa, thyroid disease, gestational diabetes mellitus and the interaction between each potential confounding factor and gestation duration. In male fetuses, the interaction between FET and gestational duration (estimate: 0.36; 95% CI: 0.06 to 0.67) significantly affected the EFW. Similarly, in female fetuses, FET (estimate: -69.85; 95% CI: -112.09 to -27.61) and the interaction between FET and gestation duration (estimate: 0.57; 95% CI: 0.28 to 0.87) significantly affected the EFW.

CONCLUSIONS

This study shows that FET affects intrauterine growth trajectory from the second trimester to term, particularly in female fetuses. Our findings require further prospective research to examine the effect of infertility treatment on fetal growth.

Expression level of long noncoding RNA H19 of normotensive placentas in late pregnancy relates to the fetal growth restriction

AIM

Infants with fetal growth restriction (FGR) are at an increased risk of perinatal morbidity and mortality. The long noncoding RNA H19 gene is expressed abundantly in placental villi and recent studies suggest that it regulates FGR. However, the role of H19 in the FGR placenta remains unclear. This study aimed to clarify the relationship between H19 expression and FGR using normotensive placentas after 34 weeks of gestation.

METHODS

Formalin-fixed paraffin-embedded tissues from human placentas collected from pregnancies resulting in small for gestational age (SGA) and appropriate for gestational age (AGA) newborns were used. The histopathological features of placenta tissues, such as villous stromal fibrosis, the numbers of terminal villi, villous vessels and cytotrophoblasts were analyzed using hematoxylin and eosin, Masson's trichrome staining and immunostaining. The localization and expression of H19 in the placentas were demonstrated by in situ hybridization and reverse transcription-quantitative polymerase chain reaction (RT-qPCR), respectively. Moreover, the expression levels of H19-regulated molecules such as IGF2 and decorin (DCN) were measured by RT-qPCR.

RESULTS

Histopathological features of the placental villous were not different between placentas associated with SGA and AGA. H19 localized to the villous stroma, endothelial cells and cytotrophoblasts. Moreover, the expression level of H19 in SGA placentas was significantly lower than that in AGA placentas. The expression levels of IGF2 and DCN in SGA placentas tended to be lower than those in AGA placentas similarly to H19.

CONCLUSION

This study highlights the potential importance of regulatory events mediated by H19 in SGA placentas without histopathological abnormalities in late pregnancy.

Stratified analysis of the correlation between gestational weight gain and birth weight for gestational age: a retrospective single-center cohort study in Japan

BACKGROUND

Japan has an exceptionally high proportion of low-weight births and underweight women. It has been suggested that an appropriate increase in gestational weight gain (GWG) for underweight women will help to prevent low birth weight. The current strategy aims to raise the desired value of GWG equally for all pregnant women within the underweight category. However, it remains elusive whether or not the relationship between GWG and birth weight for gestational age (BW/GA) are uniformly equivalent for all the women.

METHODS

We performed a retrospective cohort analysis of women who delivered their newborns at Tokyo Medical and Dental University Hospital from 2013 to 2017. First, in order to examine the direct effect of an increase or decrease in GWG on BW/GA, we analyzed the correlation between inter-pregnancy differences in GWG and BW/GA using a sub-cohort of women who experienced two deliveries during the study period (n = 75). Second, we dichotomized the main cohort (n = 1114) according to BW/GA to verify our hypothesis that the correlation between GWG and BW/GA differs depending on the size of the newborn.

RESULTS

The inter-pregnancy difference in BW/GA was not correlated with that of GWG. However, the correlation between BW/GA of siblings was high (r = 0.63, p = 1.9 × 10^- 9). The correlation between GWG and BW/GA in women who delivered larger-sized newborns was higher (r = 0.17, p = 4.1 × 10^- 5) than that in women who delivered smaller-sized newborns (r = 0.099, p = 1.9 × 10^- 2). This disparity did not change after adjustment for pre-pregnancy BMI. The mean birth weight in the dichotomized groups corresponded to percentile 52.0 and 13.4 of the international newborn size assessed by INTERGROWTH-21st standards.

CONCLUSIONS

In our study, GWG was positively correlated with BW/GA for heavier neonates whose birth weights were similar to the average neonatal weight according to world standards. However, caution might be required for low-birth-weight neonates because increased GWG does not always result in increased birth weight.

Assessing body dissatisfaction in Japanese women during the second trimester of pregnancy using a new figure rating scale

During pregnancy, women re-evaluate their body image based on their increasing body weight. They are usually concerned about their body size, which leads to body dissatisfaction. In this study, we investigated body dissatisfaction among Japanese women during the second trimester, when they are recommended to gain adequate weight. A cross-sectional survey of body dissatisfaction among pregnant women was conducted using a new figure rating scale corresponding to body mass index with real-life photographs of women in their sixth month of gestation. Pregnant Japanese women expressed body dissatisfaction and preferred to be thinner by 1.6 kg/m² of their body mass index. They perceived their body size as larger than their real size, and those with a higher body mass index had more body dissatisfaction, although they were of normal weight or underweight. The results indicated that the new figure rating scale could be a useful tool to identify pregnant women with higher body dissatisfaction during the second trimester, providing an opportunity to discuss adequate gestational weight gain with pregnant women.

Gestational weight gain across continents and ethnicity: systematic review and meta-analysis of maternal and infant outcomes in more than one million women

BACKGROUND

The association between Institute of Medicine (IOM) guidelines and pregnancy outcomes across ethnicities is uncertain. We evaluated the associations of gestational weight gain (GWG) outside 2009 IOM guidelines, with maternal and infant outcomes across the USA, western Europe and east Asia, with subgroup analyses in Asia. The aim was to explore ethnic differences in maternal prepregnancy body mass index (BMI), GWG and health outcomes across these regions.

METHODS

Systematic review, meta-analysis and meta-regression of observational studies were used for the study. MEDLINE, MEDLINE In-Process, Embase and all Evidence-Based Medicine (EBM) Reviews were searched from 1999 to 2017. Studies were stratified by prepregnancy BMI category and total pregnancy GWG. Odds ratio (ORs) 95% confidence intervals (CI) applied recommended GWG within each BMI category as the reference. Primary outcomes were small for gestational age (SGA), preterm birth and large for gestational age (LGA). Secondary outcomes were macrosomia, caesarean section and gestational diabetes.

RESULTS

Overall, 5874 studies were identified and 23 were included (n = 1,309,136). Prepregnancy overweight/obesity in the USA, Europe and Asia was measured at 42%, 30% and 10% respectively, with underweight 5%, 3% and 17%. GWG below guidelines in the USA, Europe and Asia was 21%, 18% and 31%, and above was 51%, 51% and 37% respectively. Applying regional BMI categories in Asia showed GWG above guidelines (51%) was similar to that in the USA and Europe. GWG below guidelines was associated with a higher risk of SGA (USA/Europe [OR 1.51; CI 1.39, 1.63]; Asia [1.63; 1.45, 1.82]) and preterm birth (USA/Europe [1.35; 1.17, 1.56]; Asia [1.06; 0.78, 1.44]) than GWG within guidelines. GWG above guidelines was associated with a higher risk of LGA (USA/Europe [1.93; 1.81, 2.06]; Asia [1.68; 1.51 , 1.87]), macrosomia (USA/Europe [1.87; 1.70, 2.06]; Asia [2.18; 1.91, 2.49]) and caesarean (USA/Europe [1.26; 1.21, 1.33]; Asia [1.37; 1.30, 1.45]). Risks remained elevated when regional BMI categories were applied for GWG recommendations. More women in Asia were categorised as having GWG below guidelines using World Health Organization (WHO) (60%) compared to regional BMI categories (16%), yet WHO BMI was not accompanied by increased risks of adverse outcomes.

CONCLUSIONS

Women in the USA and western Europe have higher prepregnancy BMI and higher rates of GWG above guidelines than women in east Asia. However, when using regional BMI categories in east Asia, rates of GWG above guidelines are similar across the three continents. GWG outside guidelines is associated with adverse outcomes across all regions. If regional BMI categories are used in east Asia, IOM guidelines are applicable in the USA, western Europe and east Asia.

[Nutritional Status of Japanese Women of Childbearing Age and the Ideal Weight Range for Pregnancy]

According to the recent 2015 Nutrition Survey, the prevalence of being underweight (Body Mass Index, BMI <18.5 kg/m²) among women in their 20s is 22.3%. Women of childbearing age tend to have a lower intake of protein and their total energy intake is lower than the requirements established by the 2015 Dietary Reference Intakes for Japanese. There is a growing body of evidence showing that underweight women tend to bear small babies and that these babies have an increased risk of diabetes or cancer in their adulthood. In order to prevent Japanese women from bearing small babies, the literature has suggested that women of childbearing age should be encouraged to remain at a normal weight before pregnancy. For optimal weight gain during pregnancy, existing guidelines recommend different ranges of weight gain based on prepregnancy BMI. Owing to the absence of official GWG recommendations in Asian countries, including China and Taiwan, the US Institute of Medicine (IOM) guidelines are generally followed. However, Asian women are smaller and experience lower weight gains; therefore, excessive weight gain may lead to harmful events including macrosomia, preterm birth, preeclampsia, gestational diabetes, pregnancy-induced hypertension, and short- and long-term postpartum weight retention. Thus, an accurate GWG range should be determined for Asian women. We introduce one epidemiological study in which the optimal weight gain range was investigated by analyzing receiver-operating characteristic curves together with potential research ideas in this field with the aim of encouraging young researchers to solve this public health problem affecting mothers and children.

Maternal smoking during pregnancy and rapid weight gain from birth to early infancy

Background

Although several studies have focused on the association between maternal smoking during pregnancy and rapid weight gain (RWG) during infancy, the dose-response relationship has not yet been confirmed, and very few studies have included Asian populations. Using a record-linkage method, we examined the association between maternal smoking during pregnancy and RWG in infants at around 4 months of age to clarify the dose-response relationship.

Methods

Two databases were used: maternal check-ups during pregnancy and early infancy check-ups (between April 1, 2013 and March 31, 2014 in Okinawa, Japan) were linked via IDs and provided to us after unlinkable anonymizing. For 10,433 subjects (5229 boys and 5204 girls), we calculated the change in infants' weight z-score by subtracting the z-score of their birth weight from their weight at early infancy check-ups. Smoking exposure was categorized into five groups. We used Poisson regression to examine the association of maternal smoking during pregnancy with RWG in early infancy.

Results

Overall, 1524 (14.6%) were ex-smoker and 511 (4.9%) were current smoker. Compared with the reference category of non-smokers, the adjusted risk ratio of RWG was 1.18 (95% confidence interval [CI], 1.06–1.32) for ex-smokers, 1.18 (95% CI, 0.93–1.50) for those who smoked 1–5 cigarettes per day, 1.57 (95% CI, 1.24–2.00) for those who smoked 6–10 cigarettes per day, and 2.13 (95% CI, 1.51–3.01) for those who smoked ≥11 cigarettes per day. There was a clear dose-response relationship.

Conclusion

Our study suggests that maternal smoking during pregnancy is associated in a dose-dependent manner with increased risk of RWG in early infancy.

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Maternal smoking in pregnancy is associated with Rapid Weight Gain in early infancy.

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The association of maternal smoking with rapid weight gain was dose-dependent.

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This study was based on a large population-based dataset in Japan.

Relationship between maternal hypoglycaemia and small-for-gestational-age infants according to maternal weight status: a retrospective cohort study in two hospitals

OBJECTIVE

The relationship between pre-pregnancy body mass index (BMI) and low glucose challenge test (GCT) results by maternal weight status has not been examined. This study aimed to clarify the relationship between a low GCT result and small for gestational age (SGA) by maternal weight status.

DESIGN

A retrospective cohort study in 2 hospitals.

SETTING

This study evaluated the obstetric records of women who delivered in a general community hospital and a tertiary perinatal care centre.

PARTICIPANTS

The number of women who delivered in both hospitals between January 2012 and December 2013 and underwent GCT between 24 and 28 weeks of gestation was 2140. Participants with gestational diabetes mellitus or diabetes during pregnancy, and GCT results of ≥140 mg/dL were excluded. Finally, 1860 women were included in the study.

PRIMARY AND SECONDARY OUTCOME MEASURES

The participants were divided into low-GCT (≤90 mg/dL) and non-low-GCT groups (91-139 mg/dL). The χ² tests and multivariate logistic regression analyses were conducted to investigate the association between low GCT results and SGA by maternal weight status.

RESULTS

The incidence of SGA was 11.4% (212/1860), and 17.7% (330/1860) of the women showed low GCT results. The patients were divided into 3 groups according to their BMI (underweight, normal weight and obese). When the patients were analysed separately by their weight status after controlling for maternal age, pre-pregnancy maternal weight, maternal weight gain during pregnancy, pregnancy-induced hypertension, thyroid disease and difference in hospital, low GCT results were significantly associated with SGA (OR 2.10; 95% CI 1.14 to 3.89; p=0.02) in the underweight group.

CONCLUSIONS

Low GCT result was associated with SGA at birth among underweight women. Examination of maternal glucose tolerance and fetal growth is necessary in future investigations.

Inadequate gestational weight gain increases risk of small-for-gestational-age term birth in girls in Japan: A population-based cohort study

OBJECTIVES

Babies born small for gestational age (SGA) have a higher risk of neonatal morbidity and mortality as well as later life chronic disease. The objectives of this study were to examine the extent to which prepregnancy body mass index (BMI) and gestational weight gain (GWG) influenced risk of SGA among Japanese, and to evaluate physician response to, and potential effects on, GWG.

METHODS

We examined SGA risk as a function of maternal BMI and GWG using logistic regression with data from maternal child health handbooks obtained from women in Japan (N = 383). Physicians' written comments on weight and dietary restriction were analyzed for responses to and influence on GWG.

RESULTS

SGA babies comprised 8.6% of the sample, with 13% and 6% of the mothers being underweight and overweight, respectively, and 21.7% and 19.8% of mothers gaining less and more than the recommended amounts, respectively. In adjusted models, higher prepregnancy BMI and GWG were associated with lower risk of SGA (OR 0.71, 95% CI 0.56, 0.90; 0.75, 95% CI 0.61, 0.92 respectively) in models for girls, but not for boys. Inadequate GWG was associated with higher risk of SGA in girls (OR 6.64, 95% CI 2.18, 20.22). Physician written instructions to restrict dietary intake and weight gain followed an average weight gain of 0.69 kg/week from the previous prenatal exam, and were followed by weight gains that decreased to 0.30 kg/week.

CONCLUSIONS

Prepregnancy BMI and GWG significantly influence SGA risk in female babies. GWG may be influenced by physicians' recommendations. Am. J. Hum. Biol. 28:714-720, 2016. © 2016 Wiley Periodicals, Inc.

Relation between low 50-g glucose challenge test results and small-for-gestational-age infants

AIM

There is no consensus opinion regarding a possible relation between low 50-g glucose challenge test (GCT) results and small-for-gestational-age infants (SGA). This study aimed to clarify the relation between low 50-g GCT results and SGA, after adjusting for potential confounding factors, using a large clinical dataset.

MATERIAL AND METHODS

Our retrospective cohort study evaluated the obstetric records of women who delivered at Kofu Municipal Hospital (Japan) between January 2011 and December 2013. The exclusion criteria were gestational diabetes mellitus, diabetes in pregnancy, and GCT results of ≥140 mg/dL. Based on these criteria, we included 1603 women who had undergone a GCT between 24 and 28 weeks of gestation, and divided the subjects into a low-GCT group (≤90 mg/dL) and a non-low-GCT group (91-139 mg/dL). The χ(2) -test and multivariate logistic regression analysis were used to investigate the association between low GCT results and SGA.

RESULTS

The mean subject age was 30.4 ± 5.4 years, with 45.1% nulliparity (n = 723) and 1538 (96.0%) term deliveries. The incidence of SGA was 10.7% (172/1603), and 17.9% (287/1603) of the women had low GCT results. Low GCT results were significantly associated with an increased risk of SGA (odds ratio, 1.66; 95% confidence interval, 1.14-2.42), after controlling for maternal age, pre-pregnancy maternal weight, maternal weight gain during pregnancy, and pregnancy-induced hypertension.

CONCLUSION

It appears that there is a significant association between low GCT results and SGA. However, further studies are needed to explore the detailed mechanisms of this association.

The decline in BMI among Japanese women after World War II

The body mass index (BMI) of the Japanese is significantly lower than is found in other high-income countries. Moreover, the average BMI of Japanese women is lower than that of Japanese men, and the age-specific BMI of Japanese women has decreased over time. The average BMI of Japanese women at age 25 decreased from 21.8 in 1948 to 20.4 in 2010 whereas that of men increased from 21.4 to 22.3 over the same period. We examine the long-term BMI trend in Japan by combining several historical data sources spanning eleven decades, from 1901 to 2012, to determine not only when but also how the BMI decline among women began: whether its inception was period-specific or cohort-specific. Our nonparametric regression analysis generated five findings. First, the BMI of Japanese women peaked with the 1930s birth cohort. This means that the trend is cohort-specific. Second, the BMI of men outpaced that of women in the next cohort. Third, the BMI of Japanese children, boys and girls alike, increased steadily throughout the 20th century. Fourth, the gender difference in the BMI trend is due to a gender difference in the weight trend, not the height trend. Fifth, these BMI trends are observed in urban and rural populations alike. We conclude that the BMI decline among Japanese women began with those who were in their late teens shortly after World War II.

Early gestational weight gains within current recommendations result in increased risk of gestational diabetes mellitus among Korean women

BACKGROUND

We prospectively assessed whether maternal weight gain at 24-28 weeks of gestation (MWG24) influences the risk of developing gestational complications, such as gestational diabetes mellitus (GDM) and other adverse pregnancy outcomes, in pregnant Korean women.

METHODS

Maternal weight gain from self-reported pre-pregnancy weight until 24-28 weeks of gestation was measured in 731 pregnant women, and an expected MWG24 was determined using the Institute of Medicine 2009 guidelines. Glucose tolerance, insulin resistance, insulin secretory capacity, anthropometric measurements, lipid profiles, nutrient intakes and pregnancy outcomes were evaluated at 24-28 weeks of gestation. The adjusted odds ratios (ORs) for GDM, large-for-gestational-age infants, small-for-gestational-age infants and preterm delivery were determined according to maternal weight gain by logistic regression analysis after adjusting for covariates.

RESULTS

Compared with a normal MWG24, an inadequate MWG24 reduced the OR (0.565) for GDM, but an excessive MWG24 did not affect the OR (0.854). However, ORs for preterm delivery were significantly higher in both inadequate and excessive MWG24 groups in comparison with the normal MWG24. There were no other adverse pregnancy outcomes due to the inadequate MWG24. MWG24 was not associated with a significant increase in ORs for delivering large-for-gestational-age or small-for-gestational-age infants or delivery by caesarean section. Although energy intake was less than the estimated energy requirement in all groups, MWG24 was linearly associated with energy intake such that energy balance was positive in the excessive MWG24 group.

CONCLUSIONS

This study suggests that both target weight gain and energy intake recommendations for early pregnancy may not be optimal for Korean women and that race-specific recommendations are needed to decrease the risk of GDM without increasing adverse pregnancy outcomes.

Associations of maternal pre-pregnancy underweight with small-for-gestational-age and spontaneous preterm birth, and optimal gestational weight gain in Japanese women

AIM

To determine associations of maternal pre-pregnancy underweight with poor outcomes and evaluate how gestational weight gain affects risks for such outcomes in pre-pregnancy underweight Japanese women.

METHODS

By analyzing the January 2001-December 2012 hospital database, we retrospectively identified 6954 women with pre-pregnancy normal weights (body mass index, 18.5-24.9 kg/m²) and 1057 pre-pregnancy underweight women (body mass index, <18.5 kg/m²) who delivered at the Perinatal Maternity and Neonatal Center of Yokohama City University. These women were stratified by weekly weight gain during the second/third trimesters to investigate associations of gestational weight gain with spontaneous preterm birth and small for gestational age (SGA). Spontaneous preterm birth and SGA incidences were compared with those of women meeting Institute of Medicine (IO M) guidelines to determine optimal weight gain in Japanese women.

RESULTS

Preterm birth and SGA incidences were significantly higher in pre-pregnancy underweight than in pre-pregnancy normal weight women (4.6% vs 2.4% [P=0.005] and 13.9% vs 9.7% [P = 0.003], respectively). For pre-pregnancy normal weight women, preterm birth incidence was significantly higher in those with weight gain of less than 0.2 kg/week than in those IOM guidelines. For pre-pregnancy underweight women, preterm birth and SGA incidences were significantly higher in those with weight gain of less than 0.3 kg/week than in those meeting IOM guidelines.

CONCLUSION

Preterm birth and SGA incidences did not differ significantly between pre-pregnancy normal weight women with weight gain of 0.2 kg/week or more and pre-pregnancy underweight women with weight gain of 0.3 kg/week or more, as compared to women meeting IOM guidelines. These results suggest that IOM guidelines for gestational weight gain may lack external validity in Japanese women.