Long-term effects of selective fetal growth restriction (LEMON): a cohort study of neurodevelopmental outcome in growth discordant identical twins in the Netherlands

Reduced lung function during childhood in identical twins with discordant fetal growth: a cohort study

Background

Fetal growth restriction (FGR) can negatively affect lung development, leading to increased respiratory morbidity and reduced lung function later in life. Studies regarding the impact of FGR on lung function in singletons are influenced by genetic, obstetric, and maternal factors. To overcome these confounding factors, we aim to investigate lung function in identical twins with selective FGR (sFGR).

Methods

Lung function assessments were performed in identical twins with sFGR born in our centre between March 1, 2002, and December 31, 2017, aged between 5 and 17 years. sFGR was defined as birthweight discordance ≥20%. Outcome measures consisted of forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), and transfer factor for carbon monoxide (DLCO) and were compared between the smaller and larger twin.

Findings

Thirty-nine twin pairs performed spirometry of sufficient quality. Median gestational age at birth was 34.3 (interquartile range (IQR) 32.1-36.0) weeks with median birthweights of 1500 (IQR 1160-1880) grams and 2178 (IQR 1675-2720) grams for the smaller and larger twin, respectively. Smaller twins had significantly lower z-scores for FEV1 (-0.94 versus -0.41, p = 0.0015), FVC (-0.56 versus -0.06, p < 0.0001) and DLCO (-0.50 versus 0.00, p < 0.0001) compared to larger co-twins.

Interpretation

Although being genetically identical, sFGR in identical twins is associated with a reduction in static and dynamic lung volume and a reduction in lung diffusion, even when taking the reduced lung volume into account. This indicates that adverse growth conditions in utero negatively affect lung development and function, potentially contributing to an increase in respiratory morbidities later in life.

Funding

The Dutch Heart Foundation and The Bontius Foundation.

The changing Doppler patterns and perinatal outcomes of monochorionic diamniotic twins with selective fetal growth restriction

OBJECTIVES

To investigate the clinical outcomes and Doppler patterns changes in monochorionic diamniotic (MCDA) twins with selective fetal growth restriction (sFGR).

METHODS

We retrospectively analyzed 362 sFGR cases from January 2010 to May 2016 at a single tertiary referral center. The Doppler waveforms of umbilical artery end-diastolic flow were collected, and all neonates were subjected to an early neonatal brain scan.

RESULTS

A total of 66/100 (66 %) type I cases were stable, whereas 25/100 (25 %) cases changed to type II and 9/100 (9 %) changed to sFGR complicated twin-twin transfusion syndrome (TTTS). A total of 48.9 % (22/45) sFGR cases were complicated with polyhydramnios and 30.4 % (7/23) sFGR cases were complicated with oligohydramnios, both of which were progressed to sFGR with TTTS. Mild cerebral injury was significantly associated with Doppler flow abnormalities, earlier gestational age at delivery and type of sFGR diagnosis. Severe cerebral injury was significantly associated with gestational age at delivery (31.6 vs. 34.1, p=0.002) and larger birthweight discordance (43.9 vs. 29.3 %, p=0.011).

CONCLUSIONS

Doppler patterns in sFGR can gradually change, with important consequences with regard to management and outcomes. Along with abnormal Doppler findings, earlier occurrence of sFGR and delivery are associated with subsequent neonatal cerebral injury.

Prenatal phthalate exposure and neurodevelopmental differences in twins at 2 years of age

BACKGROUND

Previous studies of singletons evaluating prenatal phthalate exposure and early neurodevelopment reported mixed results and the associations could be biased by parental, obstetrical, and genetic factors.

METHODS

A co-twin control design was employed to test whether prenatal phthalate exposure was associated with children's neurocognitive development. We collected information from 97 mother-twin pairs enrolled in the Wuhan Twin Birth Cohort between March 2016 and October 2018. Fourteen phthalate metabolites were measured in maternal urine collected at each trimester. Neurodevelopmental differences in twins at the age of two were examined as the outcome of interest. Multiple informant model was used to examine the covariate-adjusted associations of prenatal phthalate exposure with mental development index (MDI) and psychomotor development index (PDI) scores assessed at 2 years of age based on Bayley Scales of Infant Development (Second Edition). This model also helps to identify the exposure window of susceptibility.

RESULTS

Maternal urinary levels of mono-2-ethyl-5-oxohexyl phthalate (MEOHP) (β = 1.91, 95% CI: 0.43, 3.39), mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) (β = 1.56, 95% CI: 0.33, 2.79), and the sum of di-(2-ethylhexyl) phthalate metabolites (∑DEHP) (β = 1.85, 95% CI: 0.39, 3.31) during the first trimester showed the strongest and significant positive associations with intra-twin MDI difference. When stratified with twin chorionicity, the positive associations of monoethyl phthalate (MEP), monoisobutyl phthalate (MiBP), mono-n-butyl phthalate (MBP), monobenzyl phthalate (MBzP), individual DEHP metabolites, and ∑DEHP exposure during pregnancy with intra-twin neurodevelopmental differences were more significant in monochorionic diamniotic (MCDA) twins than those in dichorionic diamniotic (DCDA) twins.

CONCLUSIONS

Neurodevelopmental differences in MCDA twins were strongly associated with prenatal phthalate exposure. Our findings warrant further confirmation in longitudinal studies with larger sample sizes.

Neurodevelopmental outcome in complicated twin pregnancy: prospective observational study

OBJECTIVE

Twin pregnancy is associated with increased perinatal mortality and morbidity, but long-term neurodevelopmental outcome remains underinvestigated. The primary objective of this study was to investigate the incidence of adverse neurodevelopment after 1 year of age in complicated monochorionic diamniotic (MCDA) twin pregnancies compared with uncomplicated twin pregnancies.

METHODS

This was a prospective cohort study conducted at St George's University Hospital NHS Foundation Trust, London, UK. Women with a twin pregnancy culminating in at least one surviving child, aged between 12 and 60 months (corrected for prematurity) at the time of assessment, were invited to complete the relevant Ages and Stages Questionnaire® version 3 (ASQ-3) test. The two study groups were: (1) complicated MCDA twin pregnancies, including those with twin-twin transfusion syndrome, twin anemia-polycythemia sequence, selective fetal growth restriction, twin reversed arterial perfusion sequence and/or single intrauterine demise; and (2) uncomplicated MCDA and dichorionic diamniotic twin pregnancies. The primary outcome measure was an abnormal ASQ-3 score, defined as a score of more than 2 SD below the mean in any one of the five domains. Mixed-effects multivariable logistic regression analysis was performed to determine whether a complicated MCDA twin pregnancy was associated independently with an abnormal ASQ-3 score.

RESULTS

The study included 174 parents who completed the questionnaire for one or both twins; therefore, 327 ASQ-3 questionnaires were available for analysis. Of those, 117 (35.8%) were complicated MCDA twin pregnancies and 210 (64.2%) were controls. The overall rate of an abnormal ASQ-3 score in children born of a complicated MCDA twin pregnancy was nearly double that of those from uncomplicated twin pregnancies (14.5% vs 7.6%; P = 0.056). Children born of a complicated MCDA twin pregnancy had a significantly higher rate of impairment in the gross-motor domain compared with the control group (8.5% vs 2.9%; P = 0.031). Complicated MCDA twin pregnancies that underwent prenatal intervention had a significantly higher rate of abnormal ASQ-3 score compared with those that did not undergo prenatal intervention (28.1% vs 1.7%; P < 0.001). On multilevel logistic regression analysis, complicated MCDA twin pregnancy was an independent predictor of abnormal ASQ-3 score (adjusted odds ratio, 3.28 (95% CI, 3.27-3.29); P < 0.001).

CONCLUSIONS

This study demonstrates that survivors of complicated MCDA twin pregnancies have a higher rate of adverse neurodevelopmental outcome, independently of prematurity. Long-term neurodevelopmental follow-up in these pregnancies can ensure timely and optimal management of those affected. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Amniotic fluid metabolic fingerprinting contributes to shaping the unfavourable intrauterine environment in monochorionic diamniotic twins

BACKGROUND & AIMS

Amniotic fluid (AF) is the primary intrauterine environment for fetal growth throughout gestation. Selective fetal growth restriction (sFGR) is an adverse complication characterized by unequal growth in twins with nearly identical genetic makeup. However, the influence of AF-mediated intrauterine environment on the development and progression of sFGR remains unexplored.

METHODS

High-throughput targeted metabolomics analysis (G350) was performed on AF samples collected from sFGR (n = 18) and MCDA twins with birth weight concordance (MCDA-C, n = 20) cases. Weighted correlation network analysis (WGCNA) was used to identify clinical features that may influence the metabolite composition in AF. Subsequently, partial least-squares discriminant analysis (PLS-DA) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed to compare the different types of sFGR and MCDA-C twins. Receiver operating characteristic (ROC) and multivariate ROC curves were utilized to explore potential AF markers in twins with sFGR.

RESULTS

In our study, 182 metabolites were quantified in 76 AF samples. WGCNA indicated that the metabolite composition in late AF may not be influenced by gestational age. PLSDA demonstrated distinct variations between the metabolite profiles of AF in the sFGR and MCDA-C twins, with a significant emphasis on amino acids as the primary differential metabolite. The dissimilarities observed in sFGR twins were predominantly attributed to lipid metabolism-related metabolites. In particular, the KEGG enrichment metabolic pathway analysis revealed significant associations of both types of sFGR twins with central carbon metabolism in cancer. The multivariate ROC curves indicated that the combination of carnosine, sarcosine, l-alanine, beta-alanine, and alpha-n-phenylacetylglutamine significantly improved the AUC to 0.928. Notably, the ROC curves highlighted creatine (AUC:0.934) may be a potential biomarker for severe sFGR.

CONCLUSION

The data presented in this study offer a comprehensive metabolic map of the AF in cases of sFGR, shedding light on potential biomarkers associated with fetal growth and development in MCDA twins.

Birth weight discordance in very and extremely preterm twins and the risk of neonatal hearing loss

OBJECTIVE

Birth weight (BW) discordant twins have an increased risk of mortality and morbidity. We aimed to study the effect of BW discordance on the risk of neonatal hearing loss (NHL) in very and extremely preterm twins.

STUDY DESIGN

Results of the nationwide newborn hearing screening program in Dutch Neonatal Intensive Care Units and diagnostic examination were centrally registered between 2003 and 2021 and included in this study. We selected twins and singletons with a gestational age (GA) 24- < 32 weeks. Logistic regression analyses were applied to study the effect of BW discordance on the risk of NHL adjusted for BW, GA and sex. Singletons and concordant twins, defined as a BW discordance of ≤20 %, were used as two reference groups. BW discordance was further categorized as medium (>20-30 %) and high (>30 %).

RESULTS

In total, 3430 twins (2694 concordant, 428 medium and 308 high BW discordant), and 23,114 singletons were available. Smaller newborns of high BW discordant twins showed an increased risk of NHL compared to singletons (adjusted odds ratio with 95 % confidence interval was 3.56 (2.26-5.60)). Also, smaller newborns of medium and high BW discordant twins showed an increased risk of NHL compared to concordant twins (adjusted odds ratio with 95 % confidence interval were 1.97 (1.13-3.44) and 4.17 (2.56-6.82), respectively). No other statistically significant differences were found.

CONCLUSION

BW discordance increased the risk of NHL in the smaller of the twin born very or extremely preterm. This risk increased as the weight difference increased.

Metabolic dynamics and prediction of sFGR and adverse fetal outcomes: a prospective longitudinal cohort study

BACKGROUND

Selective fetal growth restriction (sFGR) is an extreme complication that significantly increases the risk of perinatal mortality and long-term adverse neurological outcomes in offspring, affecting approximately 15% of monochorionic diamniotic (MCDA) twin pregnancies. The lack of longitudinal cohort studies hinders the early prediction and intervention of sFGR.

METHODS

We constructed a prospective longitudinal cohort study of sFGR, and quantified 25 key metabolites in 337 samples from maternal plasma in the first, second, and third trimester and from cord plasma. In particular, our study examined fetal growth and brain injury data from ultrasonography and used the Ages and Stages Questionnaire-third edition subscale (ASQ-3) to evaluate the long-term neurocognitive behavioral development of infants aged 2-3 years. Furthermore, we correlated metabolite levels with ultrasound data, including physical development and brain injury indicators, and ASQ-3 data using Spearman's-based correlation tests. In addition, special combinations of differential metabolites were used to construct predictive models for the occurrence of sFGR and fetal brain injury.

RESULTS

Our findings revealed various dynamic patterns for these metabolites during pregnancy and a maximum of differential metabolites between sFGR and MCDA in the second trimester (n = 8). The combination of L-phenylalanine, L-leucine, and L-isoleucine in the second trimester, which were closely related to fetal growth indicators, was highly predictive of sFGR occurrence (area under the curve [AUC]: 0.878). The combination of L-serine, L-histidine, and L-arginine in the first trimester and creatinine in the second trimester was correlated with long-term neurocognitive behavioral development and showed the capacity to identify fetal brain injury with high accuracy (AUC: 0.94).

CONCLUSIONS

The performance of maternal plasma metabolites from the first and second trimester is superior to those from the third trimester and cord plasma in discerning sFGR and fetal brain injury. These metabolites may serve as useful biomarkers for early prediction and promising targets for early intervention in clinical settings.

Impact of early-onset fetal growth restriction on the neurodevelopmental outcome of very preterm infants at 24 months: a retrospective cohort study

BACKGROUND

The association between fetal growth restriction (FGR) and childhood neurodevelopmental delay is unclear and the evidence available to the present date shows conflicting results. Our aim was to analyse the impact of early-onset FGR on the neurodevelopmental outcome at 24 months of corrected age in very preterm infants.

METHODS

Retrospective cohort study of very preterm infants (≤ 32 weeks' gestation) admitted to a neonatal intensive care unit between 1 January 2013-31 December 2019. The control group comprised appropriate for gestational age (AGA) newborns. Griffiths III Mental Development Scale was performed at 24 months of corrected age.

RESULTS

132 infants were included: 44 FGR and 88 AGA. Mean Global Development Quotient (GDQ) was lower for FGR infants (p = 0.004) even after adjusting for maternal and perinatal factors (βadjusted -16.703; p = 0.009). The average scores for the neurodevelopmental domains were highest for personal-social-emotional skills (107.02 ± 16.34), followed by eye/hand coordination (105.61 ± 14.20) and foundation of learning skills (102.23 ± 13.74) and were lowest for gross motor (97.90 ± 11.88) and language/communication skills (96.39 ± 18.88). FGR had a significant negative impact on all domains except for gross motor skills. After adjustment, FGR continued to have a significant adverse impact on language/communication (βadjusted -21.924; p = 0.013), eye/hand coordination (βadjusted -15.446; p = 0.015) and foundation of learning skills (βadjusted -15.211; p = 0.013).

CONCLUSIONS

In very preterm infants, FGR was associated with a significantly increased risk of poor neurodevelopmental outcome at 24 months of corrected age compared to age-matched AGA infants.

Outcome following laser surgery of twin-twin transfusion syndrome complicated by selective fetal growth restriction: systematic review and meta-analysis

OBJECTIVE

The published literature reports mostly on the outcome of twin pregnancies complicated by twin-twin transfusion syndrome (TTTS) without considering whether the pregnancy is also complicated by another pathology, such as selective fetal growth restriction (sFGR). The aim of this systematic review was to report on the outcome of monochorionic diamniotic (MCDA) twin pregnancies undergoing laser surgery for TTTS that were complicated by sFGR and those not complicated by sFGR.

METHODS

MEDLINE, EMBASE and Cochrane databases were searched. The inclusion criteria were studies reporting on MCDA twin pregnancies with TTTS undergoing laser therapy that were complicated by sFGR and those not complicated by sFGR. The primary outcome was the overall fetal loss following laser surgery, defined as miscarriage and intrauterine death. The secondary outcomes included fetal loss within 24 h after laser surgery, survival at birth, preterm birth (PTB) prior to 32 weeks of gestation, PTB prior to 28 weeks, composite neonatal morbidity, neurological and respiratory morbidity, and survival free from neurological impairment. All outcomes were explored in the overall population of twin pregnancies complicated by sFGR vs those not complicated by sFGR in the setting of TTTS and in the donor and recipient twins separately. Random-effects meta-analysis was used to combine data and the results are reported as pooled odds ratios (OR) with 95% CI.

RESULTS

Five studies (1710 MCDA twin pregnancies) were included in the qualitative synthesis and four in the meta-analysis. The overall risk of fetal loss after laser surgery was significantly higher in MCDA twin pregnancies with TTTS complicated by sFGR (20.90% vs 14.42%), with a pooled OR of 1.6 (95% CI, 1.3-1.9) (P < 0.001). The risk of fetal loss was significantly higher in MCDA twin pregnancies with TTTS and sFGR for the donor but not for the recipient twin. The rate of live twins was 79.1% (95% CI, 72.6-84.9%) in TTTS pregnancies with sFGR and 85.6% (95% CI, 81.0-89.6%) in those without sFGR (pooled OR, 0.6 (95% CI, 0.5-0.8)) (P < 0.001). There was no significant difference in the risk of PTB prior to 32 weeks of gestation (P = 0.308) or prior to 28 weeks (P = 0.310). Assessment of short- and long-term morbidity was affected by the small number of cases. There was no significant difference in the risk of composite (P = 0.506) or respiratory (P = 0.531) morbidity between twins complicated by TTTS with vs those without sFGR, while the risk of neurological morbidity was significantly higher in those with TTTS and sFGR (pooled OR, 1.8 (95% CI, 1.1-2.9)) (P = 0.034). The risk of neurological morbidity was significantly higher for the donor twin (pooled OR, 2.4 (95% CI, 1.1-5.2)) (P = 0.029) but not for the recipient twin (P = 0.361). Survival free from neurological impairment was observed in 70.8% (95% CI, 45.0-91.0%) of twin pregnancies with TTTS complicated by sFGR and in 75.8% (95% CI, 51.9-93.3%) of those not complicated by sFGR, with no difference between the two groups.

CONCLUSIONS

sFGR in MCDA pregnancies with TTTS represents an additional risk factor for fetal loss following laser surgery. The findings of this meta-analysis may be useful for individualized risk assessment of twin pregnancy complicated by TTTS and tailored counseling of the parents prior to laser surgery. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Fetal growth restriction inhibits childhood growth despite catch-up in discordant identical twins: an observational cohort study

OBJECTIVE

Research suggests that postnatal catch-up growth after fetal growth restriction (FGR) occurs frequently. Yet, postnatal growth in singletons may be influenced by multiple factors. Identical twins with discordant prenatal growth, termed selective FGR (sFGR), can be regarded as a natural experiment eliminating these sources of bias.

DESIGN

Observational cohort study.

METHODS

Monochorionic twins with sFGR born between 2002 and 2017 (aged 3-17 years) were eligible. Growth measurements (height, weight, head circumference, and body mass index) were performed at follow-up. Detailed growth curves documented by a systematic primary care system in the Netherlands were collected. Measurements were converted to standard deviation scores (SDSs). A mixed-effects model was used to assess within-pair SDS difference and individual height SDS relative to target height SDS.

RESULTS

Forty-seven twin pairs (94 children) were included at a median age of 11 (interquartile range 8-13) years. At the last measurement, smaller twins at birth had a lower height SDS [-0.6 vs -0.3, P < .001, median difference 0.5 (95%CI 0.4-0.7)], lower weight SDS [-0.5 vs -0.1, P < .001, median difference 0.8 (95%CI 0.5-1.0)], and lower head circumference SDS [-0.5 vs 0.2, P < .001, median difference 0.8 (95%CI 0.6-0.9)] compared to larger twins. These differences persisted until the age of 17. Smaller twins showed rapid catch-up growth in the first 2 years and reached their target height range between 8 and 11 years.

CONCLUSIONS

Identical twins with discordant prenatal growth maintain a modest but significant difference in height, weight, and head circumference, indicating a persistent, inhibitory effect of an adverse intrauterine environment on childhood growth.

Extrauterine Growth Restriction and Optimal Growth of Very Preterm Neonates: State of the Art

Over the last few decades, there has been an ongoing debate over both the optimal feeding mode for very premature neonates (VPN) as well as what their optimal growth should be. Despite the American Academy of Pediatric declaring since 1997 that the growth of VPN should follow the trajectory of intrauterine fetal growth, differences of opinion persist, feeding policies keep changing, and the growth and development of VPN remains extremely variable not only between countries, but even between neighboring neonatal units. Even the appropriate terminology to express poor postnatal growth (extrauterine growth restriction (EGR) and postnatal growth failure (PGF)) remains a subject of ongoing discussion. A number of recent publications have shown that by implementing breast milk fortification and closely following growth and adjusting nutrition accordingly, as per the consensus guidelines of the major Neonatal Societies, we could achieve growth that closely follows birth centiles. A recent position paper from EPSGAN recommending targeted nutritional support to cover the energy and protein deficits sustained by VPN during periods of critical illness further strengthens the above findings. Conclusion: We can promote better growth of VPN by ensuring a stable administration of sufficient calories and protein, especially in the first 2 weeks of life, implementing breast milk fortification, covering energy and protein deficits due to critical illness, and increasing feeding volumes as per the latest guidelines. The adoption of universal protocol for nutrition and growth of VPN is essential and will enable better monitoring of long-term outcomes for this population.

Classification and Special Nutritional Needs of SGA Infants and Neonates of Multiple Pregnancies

Data regarding the nutritional management of preterm small for gestational age (SGA) infants are scarce. In the recent report of ESPGHAN, the recommended energy for very preterm infants during hospitalization has been increased, yet this may not fit the needs of all preterm infants. It is important to distinguish fetal growth-restricted (FGR) infants from constitutional SGA infants, as well as preterm SGA from preterm AGA infants, since they may have different nutritional needs. Preterm FGR infants, and specifically infants < 29 weeks' gestation, accumulate nutrient deficits due to intrauterine malnutrition, prematurity, morbidities, delayed initiation of feeding, and feeding intolerance. Therefore, these infants may need more aggressive nutrition for optimal catch-up growth and neurologic development. However, a balance should be kept between optimal and excessive catch-up growth, since the combination of intrauterine malnutrition and excessive postnatal growth has been linked with later adverse metabolic consequences. Furthermore, multiple gestation is often complicated by FGR and prematurity. There is controversy in the definition of FGR in multiple gestations, and it should be noted that FGR in multiple gestation usually differs etiologically from FGR in singletons. The aim of this review is to summarize existing knowledge regarding the nutritional needs of preterm FGR and FGR infants of multiple gestation.

Pre-birth acquisition of personhood: Incremental accrual of attributes as the framework for individualization by serial and concurrently acting developmental factors

Discrete events and processes influence development of individual humans. Attribution of personhood to any individual human being cannot be disconnected from the underlying biological events and processes of early human development. Nonetheless, the philosophical, sociological and legal components that are integral to the meaning of the term as commonly used cannot be deduced from biology alone. The challenge for biomedical scientists to inform discussion in this arena then rests on profiling the key biological events and processes that must be assessed when considering how one might objectively reason about the task of superimposing the concept of personhood onto the developing biological entity of a potential human being. Endogenous genetic and epigenetic events and exogenous developmental milieu processes diversify developmental trajectories of potential individual humans prior to livebirth. First, fertilization and epigenetic resetting of each individual's organismic clock to time zero (t = 0) at the gastrulation/primitive streak stage (day 15 of embryogenesis), are two discrete unseen biological events that impact a potential individual human's attributes. Second, those two discrete unseen biological events are immersed in the continuous developmental process spanning pre-fertilization and gestation, further driving individualization of diverse attributes of each future human before the third discrete and blatant biological event of parturition and livebirth. Exposures of the gravida to multiple diverse exogenous exposures means that morphogenesis and physiogenesis of every embryo/fetus has individualized attributes for its future human lifespan. Our proposed framework based on the biological discrete events and processes spanning pre-fertilization and prenatal development, implies that personhood should be incrementally attributed, and societal protections should be graduated and applied progressively across the pre-birth timespan.

Sibling rivalry between twins in utero and childhood: Evidence from birthweight and survival of 95 919 twin pairs in 72 low- and middle-income countries

BACKGROUND

This study explores the magnitude and timing of sex and gender disparities in child development by describing differences in health outcomes for male and female siblings, comparing twins to control for all aspects of life circumstances other than sex and gender.

METHODS

We construct a repeat cross-sectional dataset of 191 838 twins among 1.7 million births recorded in 214 nationally representative household surveys for 72 countries between 1990 and 2016. To test for biological or social mechanisms that might favor the health of male or female infants, we describe differences in birthweights, attained heights, weights, and survival to distinguish gestational health from care practices after each child is born.

RESULTS

We find that male fetuses grow at the expense of their co-twin, significantly reducing their sibling's birthweight and survival probabilities, but only if the other fetus is male. Female fetuses are born significantly heavier when they share the uterus with a male co-twin and have no significant difference in survival probability whether they happen to draw a male or a female co-twin. These findings demonstrate that sex-specific sibling rivalry and male frailty begin in utero, prior to gender bias after birth that typically favors male children.

CONCLUSIONS

Sex differences in child health may have competing effects with gender bias that occurs during childhood. Worse health outcomes for males with a male co-twin could be linked to hormone levels or male frailty, and could lead to underestimates of the effect sizes of later gender bias against girls. Gender bias favoring surviving male children may explain the lack of differences in height and weight observed for twins with either male or female co-twins.

Perinatal Outcomes and Neurodevelopment 1 Year after Birth in Discordant Twins According to Chorionicity

Background and Objectives: This study aimed to compare maternal complications, perinatal outcomes, and neurodevelopment 1 year after the birth between concordant and discordant twins in monochorionic and dichorionic twins. Materials and Methods: This retrospective study included twin pregnancies delivered between 24 + 1 and 38 + 2 weeks of gestation between January 2011 and September 2019. Chorionicity was confirmed by ultrasonography and was categorized into monochorionic and dichorionic. Each was then divided into two groups (concordant and discordant) according to birth weight discordancy. Maternal complications and neonatal outcomes, including neurodevelopmental delays, were compared between the two groups. Results: A total of 298 pairs of twin pregnancies were enrolled, of which 58 (19.26%) women were pregnant with monochorionic diamniotic twins and 240 (80.54%) with dichorionic diamniotic twins. In both monochorionic and dichorionic twins, the discordant twins had a greater incidence of emergency deliveries because of iatrogenic causes than the concordant twins. Among dichorionic twins, discordant twins had lower birth weight rates and higher hospitalization rates and morbidities than concordant twins. Among monochorionic twins, discordant twins had a lower birth weight and higher neonatal mortality than concordant twins. The neonatal size was not a predictor of neurodevelopment in this group. Based on the logistic regression analysis, male sex, respiratory distress syndrome, and bronchopulmonary dysplasia were risk factors for the neurodevelopmental delay; birth weight discordancy was significant only in dichorionic twins. Conclusions: Perinatal outcomes in discordant twins may be poor, and neurodevelopment 1 year after birth was worse in discordant twins than in concordant twins. Discordancy in twins can be a risk factor for neurodevelopmental delay.

Insecure attachment and internalizing behavior problems in growth discordant identical twins

BACKGROUND

Psychosocial development in monochorionic (MC) twins born after selective fetal growth restriction (sFGR) has been unreported to date, despite its importance for daily functioning and future relationships.

AIMS

To investigate psychosocial development, attachment and school functioning in MC twins with sFGR and compare outcomes with the general population and between smaller and larger twins.

STUDY DESIGN

Observational cohort study.

SUBJECTS

MC twins with sFGR (defined as a birth weight discordance ≥20 %) born between 2002 and 2017 and aged 3-17 years.

OUTCOME MEASURES

Multiple parent report questionnaires: the Child Behavior Checklist (social-emotional development and behavior), the (Early) Childhood Behavior Questionnaire Very Short Form (temperament), the Attachment Insecurity Screening Inventory (attachment) and a school functioning questionnaire.

RESULTS

Median age for the 48 twin pairs was 11 (interquartile range (IQR) 8-13) years. Attachment insecurity for both twins was higher than in the general population for ambivalence/resistance (34 % (21/62) vs. 16 %, p = 0.024) and total attachment insecurity (35 % (22/62) vs. 16 %, p = 0.016). Smaller twins had more internalizing behavioral problems, i.e. negative emotions and behaviors turned inwards (22 % (10/46) vs. 11 % (5/46), p = 0.021) and a higher negative affect, i.e. more likely to experience negative emotions (3.2 (2.9-3.7) vs. 2.9 (2.2-3.2), p = 0.009) than larger twins, as well as a lower secondary school level (p = 0.031).

CONCLUSION

MC twins with sFGR have more ambivalent/resistant attachment insecurity following the complicated pregnancy course. Smaller twins have a tendency towards negative emotions and internalizing behaviors compared to larger twins, indicating an increased sensitivity for depression and anxiety.