Birth Cohort Study Research Articles

Risk of gestational diabetes in women with PCOS based on body mass index: The Japan Environment and Children's Study.

Women with polycystic ovary syndrome (PCOS), which is the most common endocrine disorder in women of reproductive age, have a potentially increased risk of gestational diabetes mellitus (GDM). To examine the impact of PCOS on GDM based on maternal body mass index (BMI) using data from a large birth cohort study in Japan. Prospective observational study using data from the Japan Environment and Children's Study (JECS). Singleton pregnancies in the JECS during 2011-2014 were included. Mothers with HbA1c levels of ≥6.5% in the first trimester and history of DM or steroid use during pregnancy were excluded. Participants were categorized according to their pre-pregnancy BMIs: G1 (<18.5 kg/m2), G2 (18.5-19.99 kg/m2), G3 (20.0-22.99 kg/m2), G4 (23.0-24.99 kg/m2), and G5 (≥25.0 kg/m2). The impact of PCOS on early (Ed) and late-onset (Ld) GDM for each group was estimated using a multiple logistic regression model. We included 92774 participants, comprising 2012 PCOS(+) cases. GDM occurrence was higher in women with PCOS (p<0.001). PCOS had no effect on GDM in G1, G2, and G3. In G4, PCOS increased the risk of Ed GDM (adjusted odds ratio [aOR]: 3.27, 95% confidence interval [CI]: 1.29-8.29). In G5, PCOS increased the risk of both Ed (aOR: 2.48, 95% CI: 1.53-4.02) and Ld GDM (aOR: 1.94, 95% CI: 1.23-3.07). The impact of PCOS on GDM occurrence depended on the pre-pregnancy BMIs, which may facilitate personalized preconception counseling among women with PCOS.

Prenatal exposure to per- and polyfluoroalkyl substances, fetal thyroid function, and intelligence quotient at 7 years of age: Findings from the Sheyang Mini Birth Cohort Study

Prenatal exposure to per- and polyfluoroalkyl substances, fetal thyroid function, and intelligence quotient at 7 years of age: Findings from the Sheyang Mini Birth Cohort Study

The prevalence of preterm and low birth weight infants among migrant women in the Pearl River Delta region, China: a population-based birth cohort study

BackgroundThe existing literature evaluating the association between neonatal morbidity and migrant status presents contradictory results. The purpose of this study was to compare the risk of preterm birth (PTB) and low birth weight (LBW) among newborns from local and migrant women in China’s Pearl River Delta (PRD) region.MethodsIn this observational population-based study, we included all live singleton deliveries from PRD region local women and migrant women. Data were sourced from the Guangdong Medical Birth Registry Information System between Jan 1, 2014, and Dec 31, 2020. Women were categorized into three groups by maternal migrant status: local women from PRD region, migrant women from Guangdong province or from other provinces. The outcome variables that were examined included two adverse birth outcomes: PTB and LBW. The association between the risk of PTB and LBW and maternal migrant status was assessed using logistic regression.ResultsDuring 2014–2020, 5,219,133 single live deliveries were recorded, corresponding 13.22% to local women and the rest to migrant women coming from Guangdong (53.51%) and other provinces (33.26%). PTB prevalence was highest among local women (5.79%), followed by migrant women from Guangdong (5.29%), and the lowest among migrants from other provinces (4.95%). This association did not change after including maternal age, infant sex, delivery mode, and birth season in the models. Compared to local women, migrant women from other provinces had a lower risk of LBW (4.00% vs. 4.98%, P < 0.001). The prevalence of PTB and LBW was higher among local women than migrants. The odds of delivery PTB and LBW were higher for women who were age ≥ 35. Among the three maternal migration groups, the age-LBW association displayed a typical U-shaped pattern, with those in the youngest (16–24 years) and oldest (≥ 35) age categories exhibiting the higher odds of delivering a LBW neonate. With respect to infant sex, the prevalence of PTB was significantly higher in males than females among the three maternal migration groups. An opposite trend was found for LBW, and the prevalence of LBW was higher in females among the three maternal migration groups.ConclusionThe findings of this study contribute to the understanding of the epidemiology of PTB and LBW among migrant women. Our study suggests that it is the health and robust nature of migrant mothers that predisposes them to better birth outcomes. It is important to recognize that the results of this study, while supportive of the healthy migrant effect, cannot be considered definitive without some exploration of motivation for moving and changes in lifestyle postmigration.

Maternal cardiovascular health in early pregnancy and the risk of congenital heart defects in offspring

BackgroundCongenital heart disease (CHD) is the predominant birth defect. This study aimed to explore the association between maternal cardiovascular health (CVH) and the CHD risk in offspring.MethodsWe used the prospective data from the Fujian Birth Cohort Study, collected from March 2019 to December 2022 on pregnant women within 14 weeks of gestation. Overall maternal CVH was assessed by seven CVH metrics (including physical activity, smoking, sleep duration, body mass index, blood pressure, total cholesterol, and fasting plasma glucose), with each metric classified as ideal, intermediate or poor with specific points. Participants were further allocated into high, moderate and low CVH categories based on the cumulative CVH score. The association with offspring CHD was determined with log-binominal regression models.ResultsA total of 19810 participants aged 29.7 (SD: 3.9) years were included, with 7846 (39.6%) classified as having high CVH, 10949 (55.3%) as having moderate CVH, and 1015 (5.1%) as having low CVH. The average offspring CHD rate was 2.52%, with rates of 2.35%, 2.52% and 3.84% across the high, moderate and low CVH categories, respectively (P = 0.02). Adjusted relative risks (RRs) of having offspring CHD were 0.64 (95% CI: 0.45-0.90, P = 0.001) for high CVH and 0.67 (95% CI: 0.48-0.93, P = 0.02) for moderate CVH compared to low CVH. For individual metrics, only ideal total cholesterol was significantly associated with lower offspring CHD (RR: 0.73, 95% CI: 0.59-0.83, P = 0.002).ConclusionsPregnant women of high or moderate CVH categories in early pregnancy had reduced risks of CHD in offspring, compared to those of low CVH. It is important to monitor and improve CVH during pre-pregnancy counseling and early prenatal care.

Butyrate and iso-butyrate: a new perspective on nutrition prevention of gestational diabetes mellitus

BackgroundDietary imbalance, such as a lower proportion of complex carbohydrates and a higher protein diet, may contribute to gestational diabetes mellitus (GDM) risks through their metabolisms. However, there is a lack of knowledge regarding the association between butyrate, iso-butyrate, and GDM, which are metabolisms of the two primary nutrients above. This study aimed to clarify the association of butyrate and iso-butyrate with GDM.MethodsA nested case–control study was conducted based on the Beijing Birth Cohort Study (BBCS) from 2017 to 2018. Totally, 99 singleton women were involved (GDM: n = 49, control: n = 50). All participants provided blood samples twice (in their first and second trimesters). Gas chromatography-mass spectrometry (GC-MS) was used for butyrate and iso-butyrate detection. Unconditional logistic regression and receiver operating characteristic (ROC) curve analysis were used for statistical analysis.ResultsThe results showed that butyrate in the first trimester was negatively correlated with GDM (odds ratio (OR): 0.00, 95% confidential interval (CI): 0.00–0.21, P = 0.008), and iso-butyrate in the second trimester was positively related to GDM (OR: 627.68, 95% CI: 40.51–9724.56, P < 0.001). The ratio (butyrate/iso-butyrate) was negatively associated with GDM, both in the first trimester (OR: 0.00, 95%CI: 0.00–0.05, P < 0.001) and in the second trimester (OR: 0.52, 95% CI: 0.34–0.80, P = 0.003). The area under the curve (AUC) using the ratio in the first trimester combined with clinical risk factors achieved 0.89 (95% CI: 0.83–0.95). Iso-butyrate in the second trimester combined with clinical risk factors achieved an AUC of 0.97 (95% CI: 0.92–1.00).ConclusionsHigh iso-butyrate and low butyrate levels may be associated with an increased risk of GDM. As they are produced through dietary nutrient formation by gut microbiota, further studies on the association of dietary intake and butyrate or iso-butyrate concentration in plasma may help find a novel approach to nutritional intervention for GDM.

Prenatal opioid exposure and subsequent risk of neuropsychiatric disorders in children: nationwide birth cohort study in South Korea

SummaryObjectiveTo investigate the potential association between prenatal opioid exposure and the risk of neuropsychiatric disorders in children.DesignNationwide birth cohort study.SettingFrom 1 January 2009 to 31 December 2020, birth cohort data...

Childhood Maltreatment and Intimate Partner Violence: 30-Year Follow-Up of a Birth Cohort Study

ABSTRACT Evidence of the association between childhood maltreatment (CM) and intimate partner violence (IPV) in adulthood often relies on retrospective data. This study examined the association of both retrospectively and prospectively reported CM and IPV at 30-year follow-up in 2401 participants from the same birth cohort in Queensland, Australia. The cohort was linked to CM notifications to statutory agencies made by the age of 16. Data on IPV victimization and self-reported CM came from the revised Composite Abuse Scale and Child Trauma Questionnaire, respectively. Rates of self- and agency-reported maltreatment were 589 (24.5%) and 137 (5.7%), respectively. After adjustment, self-reported maltreatment of all forms showed significant associations with all types of IPV. In the case of agency-reported CM, this was limited to significant associations between substantiated neglect or sexual abuse and the most serious IPV events, as well as overall notifications and physical IPV. Associations with agency-reported CM were strongest for females.

Systematic investigation of organochlorine pesticides and polychlorinated biphenyls blood levels in Greek children from the Rhea birth cohort suggests historical exposure to DDT and through diet to DDE

The blood levels of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) have been thoroughly investigated in Greek children from the Rhea birth cohort study. This investigation aimed to assess exposure levels, explore their possible relationship with children's age and sex, and indicate potential sources of exposure. Exposure patterns and common sources of PCBs and OCPs were analyzed using bivariate and multivariate statistics.A total of 947 blood samples from study participants were analyzed for OCP and PCB exposure, with 375 samples collected at 4 years old, 239 at 6.5 years old, and 333 at 11 years old. Elevated levels of DDE were observed in 6.5-year-old children compared to corresponding levels in other European countries. Higher levels of DDE were found in 4-year-old children, with the lowest concentrations in the 11-year-old group. The DDT/DDE ratio was consistently less than 1 among all the examined subjects. These results indicate exposure to DDT and DDE both in utero and through breastfeeding and dietary intake. For the entire cohort population, the highest concentration was determined for PCB 28, followed by PCBs 138, 153, and 180. The sum of the six indicator PCBs implied low exposure levels for the majority of the cohort population. Spearman correlations revealed strong associations between PCBs and OCPs, while principal component analysis identified two different groupings of exposure. DDE exhibited a correlation with a series of PCBs (153, 156, 163, 180), indicating a combined OCP-PCB source, and an anticorrelation with others (52, 28, 101), implying a separate and competing source.

Parental practices that influence children's development: how often are they implemented and by whom-results from the NASCITA birth cohort study.

This study aims to assess how commonly 15 parental practices, known to have positive effects on child and adult health, are carried out by families in Italy, if they are related, and which characteristics are associated with implementation. Children participating in the NASCITA Cohort, a prospective study in which family pediatricians in Italy collect data on children and their families, were included if they had sufficient data. Data on practice implementation, socio-demographic characteristics, and interrelatedness between practices were analyzed. In all, 3337 children were included. Their mothers had an average age at birth of 33years (range 17-52) and medium-high levels of education (86% of mothers) and employment (72%). No smoking or alcohol in pregnancy, supine infant sleeping position, and tummy time were the most commonly implemented practices (by over 85% of mothers, each), while the least common was exclusive breastfeeding at 6months (28%). Parental practices are related and several socio-demographic characteristics influence their implementation, with mother's educational level and geographic area of residence influencing most of the practices (each influencing 12 of 15 practices). Low educational level (OR 0.34; 95% CI 0.26-0.44), being born abroad (OR 0.43; 95% CI 0.34-0.56), and residing in the South (OR 0.49; 95% CI 0.41-0.58) most reduce the probability of implementing numerous supportive practices (all three P < 0.001). Conclusion:Socio-demographic factors contribute significantly to carrying out supportive practices. Future interventions should address the identified inequalities, prioritizing families most in need. Direct involvement of pediatricians is warranted given their favorable position for promoting positive behaviors. What is Known: • Several parental actions in the early life of a child are known to have positive effects on later child health and development. • While folic acid supplementation and exclusive breastfeeding have been promoted for years, other supporting actions are less well-known. What is New: • Rates of parental adherence to the different supportive actions varied greatly and actionswere often scantly adopted. • Socio-demographic characteristics influenced adherence, with young, unemployed mothers with low educational levels, living in the South, or who were born abroad adhering significantly less.

Medication use before and during pregnancy in Japan: the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study

Medication use before and during pregnancy in Japan: the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study

The impact of prenatal mercury on neurobehavioral functioning longitudinally assessed from a young age to pre-adolescence in a Spanish birth cohort

The objective is to investigate the relation between cord blood mercury concentrations and child neurobehavioural functioning assessed longitudinally during childhood until pre-adolescence. MethodsThe study involves mothers and their offspring engaged in the Spanish INMA birth cohort (n = 1147). Total mercury (THg) was determined in cord blood. Behavioural problems were assessed several times during childhood using the ADHD-DSM-IV at age 4, SDQ at ages 7 and 11, CPRS-R:S and the CBCL at ages 7, 9 and 11. Covariates were obtained through questionnaires during the whole period. Multivariate generalised negative binomial (MGNB) models or mixed-effects MGNB (for those tests with information at one or more time points, respectively) were used to investigate the relation between cord blood THg and the children's punctuations. Models were adjusted for prenatal fish intake. Effect modification by sex, prenatal and postnatal fish intake, prenatal fruit and vegetable intake, and maternal polychlorinated biphenyl concentrations (PCBs) was assessed by interaction terms. ResultsThe geometric mean ± standard deviation of cord blood THg was 8.22 ± 2.19 μg/L. Despite adjusting for fish consumption, our results did not show any statistically significant relationship between prenatal Hg and the children's performance on behavioural tests conducted between the ages of 4 and 11. Upon assessing the impact of various factors, we observed no statistically significant interaction. ConclusionDespite elevated prenatal THg exposure, no association was found with children's behavioural functioning assessed from early childhood to pre-adolescence. The nutrients in fish could offset the potential neurotoxic impact of Hg. Further birth cohort studies with longitudinal data are warranted.

Mother-Infant Interaction and Maternal Postnatal Psychological Distress Associate with Child's Social-Emotional Development During Early Childhood: A FinnBrain Birth Cohort Study.

We studied the effects of mother-infant interaction and maternal pre- and postnatal psychological distress on children's social-emotional problems and competences, as well as whether interaction quality moderates the association between distress and children's outcomes. Maternal pre- and postnatal psychological distress were measured using the SCL and EPDS questionnaires, whereas mother-infant interaction was measured when the child was 8months old using the EA Scales. Children's social-emotional development was measured using the BITSEA questionnaire at 2years old and using the SDQ questionnaire at 4years old, where higher maternal structuring was associated with fewer social-emotional problems in children and higher maternal sensitivity was associated with greater social-emotional competence in children at 2years old. Further, higher postnatal distress was found associated with greater social-emotional problems at 2years old, though neither these effects nor moderating effects at 4years old were observed after multiple-comparison corrections. Our findings support direct associations of both mother-infant interaction and maternal postnatal psychological distress with children's social-emotional development during toddlerhood.

Autistic traits in pregnancy linked to adverse birth outcomes

Recent studies have found that women with autism spectrum disorder (ASD) have disparities in their treatment during pregnancy, resulting in adverse birth outcomes, according to background material introducing a study of a prospective birth cohort.

Antenatal Depression and its Associated Factors: Findings from Kuwait Birth Cohort Study.

Pregnant and postpartum women are at high risk of depression due to hormonal and biological changes. Antenatal depression is understudied compared to postpartum depression and its predictors remain highly controversial. To estimate the prevalence of depressive symptoms during pregnancy and investigate factors associated with this condition including vitamin D, folate and Vitamin B12 among participants in the Kuwait Birth Study. Data collection occurred as part of the Kuwait Birth Cohort Study in which pregnant women were recruited in the second and third trimester during antenatal care visits. Data on antenatal depression were collected using the Edinburgh Postnatal Depression Scale (EPDS), considering a score of ≥ 13 as an indicator of depression. Logistic regression was used to investigate factors associated with depressive symptoms in pregnant women. Of 1108 participants in the Kuwait Birth Cohort study, 1070(96.6%) completed the EPDS. The prevalence of depressive symptoms was 21.03%(95%CI:18.62-23.59%) and 17.85%(95%CI:15.60-20.28%) as indicated by an EPDS ≥ 13 and EPDS ≥ 14 respectively. In the multivariable analysis, passive smoking at home, experiencing stressful life events during pregnancy, and a lower level of vitamin B12 were identified as predisposing factors. Conversely, having desire for the pregnancy and consumption of fruits and vegetables were inversely associated with depressive symptoms. Approximately, one fifth of pregnant women had depressive symptoms indicating the need to implement screening program for depression in pregnant women, a measure not systematically implemented in Kuwait. Specifically, screening efforts should focus on pregnant women with unintended pregnancies, exposure to passive smoking at home, and recent stressful live events.

The burden for clinical services of persons with an intellectual disability or mental disorder convicted of criminal offences: A birth cohort study of 14,605 persons followed to age 64

Background Intellectual disability (ID), schizophrenia spectrum disorder (SSD), bipolar disorder (BD), substance use disorder (SUD), and other mental disorders (OMDs) are associated with increased risks of criminality relative to sex-matched individuals without these conditions (NOIDMD). To resource psychiatric, addiction, and social services so as to provide effective treatments, further information is needed about the size of sub-groups convicted of crimes, recidivism, timing of offending, antecedents, and correlates. Stigma of persons with mental disorders could potentially be dramatically reduced if violence was prevented. Methods A birth cohort of 14,605 persons was followed to age 64 using data from Swedish national health, criminal, and social registers. Results Percentages of group members convicted of violence differed significantly: males NOIDMD, 7.3%, ID 29.2%, SSD 38.6%, BD 30.7%; SUD 44.0%, and OMD 19.3%; females NOIDMD 0.8%, ID 7.7%, SSD 11.2%, BD 2.4%, SD 17.0%, and OMD 2.1%. Violent recidivism was high. Most violent offenders in the diagnostic groups were also convicted of non-violent crimes. Prior to first diagnosis, convictions (violent or non-violent) had been acquired by over 90% of the male offenders and two-thirds of the female offenders. Physical victimization, adult comorbid SUD, childhood conduct problems, and adolescent substance misuse were each associated with increased risks of offending. Conclusion Sub-groups of cohort members with ID or mental disorders were convicted of violent and non-violent crimes to age 64 suggesting the need for treatment of primary disorders and for antisocial/aggressive behavior. Many patients engaging in violence could be identified at first contact with clinical services.

Maternal vitamin D status and risk of gestational diabetes mellitus in twin pregnancies: a longitudinal twin pregnancies birth cohort study

BackgroundGestational diabetes mellitus (GDM) is a common complication of pregnancy, with significant short-term and long-term implications for both mothers and their offspring. Previous studies have indicated the potential benefits of vitamin D in reducing the risk of GDM, yet little is known about this association in twin pregnancies. This study aimed to investigate maternal vitamin D status in the second trimester and examine its association with the risk of GDM in twin pregnancies.MethodsWe conducted a prospective cohort study based on data from the Chongqing Longitudinal Twin Study (LoTiS). Peripheral blood serum was collected from the mothers in the second trimester to measure 25(OH)D concentrations. GDM was diagnosed at 23–26 weeks of gestation using a 75-g 2-h oral glucose tolerance test. We used multivariable logistic regression analyses to examine the correlations between vitamin D status and the risk of GDM.ResultsOf the total participants, 93 (29.9%) women were diagnosed with GDM. The mean serum 25(OH)D concentration in the second trimester was 31.1 ± 11.2 ng/mL, and the rate of vitamin D insufficiency and deficiency were 23.5% and 18.7%, respectively. Compared to women with a 25(OH)D concentration < 30 ng/mL, those with a 25(OH)D concentration ≥ 30 ng/mL had a significantly lower risk of GDM (RR 0.61; 95% CI: 0.43, 0.86), especially those who were overweight before pregnancy (RR 0.32; 95% CI: 0.16, 0.64). The restricted cubic splines model showed an inverted J-shaped relationship between vitamin D concentrations and GDM risk.ConclusionsThe risk of GDM was significantly reduced in twin pregnant women with vitamin D concentrations ≥ 30 ng/mL in the second trimester.Trial registrationChiCTR-OOC-16,008,203. Retrospectively registered on 1 April 2016.

Perinatal inflammation, fetal growth restriction, and long-term neurodevelopmental impairment in Bangladesh.

There are limited data on the impact of perinatal inflammation on child neurodevelopment in low-middle income countries and among growth-restricted infants. Population-based, prospective birth cohort study of 288 infants from July 2016-March 2017 in Sylhet, Bangladesh. Umbilical cord blood was analyzed for interleukin(IL)-1α, IL-1β, IL-6, IL-8, and C-reactive protein(CRP). Child neurodevelopment was assessed at 24 months with Bayley-III Scales of Infant Development. We determined associations between cord blood inflammation and neurodevelopmental outcomes, controlling for potential confounders. 248/288 (86%) live born infants were followed until 24 months, among whom 8.9% were preterm and 45.0% small-for-gestational-age(SGA) at birth. Among all infants,elevated concentrations (>75%)of CRP and IL-6 at birth were associated with increased odds of fine motor delay at 24 months; elevated CRP was also associated with lower receptive communication z-scores. Among SGA infants, elevatedIL-1α was associated with cognitive delay, IL-8 with language delay, CRP with lower receptive communication z-scores, and IL-1β with lower expressive communication and motor z-scores. In rural Bangladesh, perinatal inflammation was associated with impaired neurodevelopment at 24 months. The associations were strongest among SGA infants and noted across several biomarkers and domains, supporting the neurobiological role of inflammation in adverse fetal development, particularly in the setting of fetalgrowth restriction. Cord blood inflammation was associated with fine motor and language delays at 24 months of age in a community-based cohort in rural Bangladesh. 23.4 million infants are born small-for-gestational-age (SGA) globally each year. Among SGA infants, the associations between cord blood inflammation and adverse outcomes were strong and consistent across several biomarkers and neurodevelopmental domains (cognitive, motor, language), supporting the neurobiological impact of inflammation prominent in growth-restricted infants. Prenatal interventions to prevent intrauterine growth restriction are needed in low- and middle-income countries and may also result in long-term benefits on child development.

Temperament and emotional overeating: the mediating role of caregiver response to children's negative emotions.

This study aimed to investigate the mediating effects of caregiver responses to a child's negative emotions on the associations between infant temperament and emotional overeating in preschool children. A sample of 358 children and their caregivers enrolled in the STRONG Kids 2 (SK2) birth cohort study (N = 468) provided data for this analysis. Caregivers completed questionnaires assessing child temperament at 3 months, caregiver response to negative emotions at 18 months, and child emotional overeating at 36 months. Structural Equation Modeling was conducted using the lavaan package in RStudio to test hypothesized models examining whether the relations between early temperament and subsequent emotional eating were mediated by caregiver responses to a child's emotions. Findings revealed that infant temperamental orienting/regulation predicted the later development of emotional overeating through supportive caregiver responses to a child's negative emotions. Lower levels of orienting/regulation were associated with greater emotional overeating, explained by less supportive caregiver responses to the child's emotions. Moreover, infant surgency had a positive direct influence on emotional overeating at 36 months. Both supportive and non-supportive caregiver responses to a child's negative emotions had significant direct influences on emotional overeating. The results highlight the importance of caregiver response to a child's negative emotions as a mediator between infant temperament and emotional overeating in preschool children. Intervention strategies can be implemented to support caregivers in adopting supportive responses to their child's negative emotions to promote healthy eating behaviors from early childhood. Future studies are needed to explore these pathways of influences throughout child development.

Sleep disturbances in late pregnancy: associations with induction of labor.

Sleep disturbances, which are common during pregnancy, may compromise labor. Nevertheless, little is known about associations between sleep disturbances and the likelihood of ending up induction of labor (IOL). Accordingly, we aimed to evaluate the connections between sleep disturbances during pregnancy and IOL. Altogether 1778 women from the FinnBrain Birth Cohort Study with gestation weeks over 37 + 6 were enrolled in the study. The women were divided into IOL (n = 331) and spontaneous onset of labor (SOL, n = 1447) groups. Sleep disturbances in late pregnancy were evaluated using the Basic Nordic Sleep Questionnaire. Logistic regression analyses were conducted with adjustments for age, body mass index, parity, smoking, and depressive symptoms. Sleep disturbances were frequent in both IOL and SOL groups. In the IOL group 43.0% and in the SOL group 39.0% had poor general sleep quality (P = 0.186). Nocturnal awakenings occurred most commonly, in 94.0% and 93.9%, respectively (P = 0.653). In the IOL group, more women (22.7%) were habitual snorers than in the SOL group (17.0%, P = 0.017), however, the difference lost the statistical significance in adjusted analysis (P = 0.848). Women in the IOL group were more likely to be short sleepers (< 7h) compared to those in the SOL group (20.2% and 15.4%, respectively, P = 0.034) with no difference after adjustment (P = 0.133). The two groups showed no differences in sleep loss (P = 0.252). Deterioration in sleep quality was noticeable in pregnant women, but it was unconnected with IOL. As the frequency of IOL is increasing, more research for related risk factors is needed.

Variation in the mu-opioid receptor gene (OPRM1) moderates the influence of maternal sensitivity on child attachment

The endogenous opioid system is thought to play an important role in mother-infant attachment. In infant rhesus macaques, variation in the μ-opioid receptor gene (OPRM1) is related to differences in attachment behavior that emerges following repeated separation from the mother; specifically, infants carrying at least one copy of the minor G allele of the OPRM1 C77G polymorphism show heightened and more persistent separation distress, as well as a pattern of increased contact-seeking behavior directed towards the mother during reunions (at the expense of affiliation with other group members). Research in adult humans has also linked the minor G allele of the analogous OPRM1 A118G polymorphism with greater interpersonal sensitivity. Adopting an interactionist approach, we examined whether OPRM1 A118G genotype and maternal (in)sensitivity are associated with child attachment style, predicting that children carrying the G allele may be more likely to develop an ambivalent attachment pattern in response to less sensitive maternal care. The sample consisted of 191 mothers participating with their children (n = 223) in the Maternal Adversity, Vulnerability and Neurodevelopment (MAVAN) project, a community-based, birth cohort study of Canadian mothers and their children assessed longitudinally across the child’s development. Maternal sensitivity was coded from at-home mother-child interactions videotaped when the child was 18 months of age. Child attachment was assessed at 36 months using the Strange Situation paradigm. As predicted, G allele carriers, but not AA homozygotes, showed increasing odds of being classified as ambivalently attached with decreasing levels of maternal sensitivity. Paralleling earlier non-human animal research, this work provides support for the theory that endogenous opioids contribute to the expression of attachment behaviors in humans.