Perinatal Outcome of Twins Compared to Singletons of the Same Gestational Age: A Case-Control Study

Comparison of neonatal outcomes between multiples and singletons among very low birth weight infants: the Korean Neonatal Network cohort study

OBJECTIVE

To compare neonatal outcomes between multiples and singletons among very low birth weight infants, this was a prospective cohort study that was conducted by collecting data registered in the Korean Neonatal Network database.

METHODS

From January 2013 to December 2016, there were 8265 infants in the Korean Neonatal Network database, and 2958 of them were from multiples. Among them, 2636 infants were twins, 308 infants were triplets, and 14 infants were quadruplets. Maternal and neonatal variables including and mortality major morbidity were compared. Finally, the predicted rates of major morbidity between singletons and multiples.

RESULTS

Multiples had higher gestational age, birth weight, Apgar score at 5 min, rates of cesarean section and artificial reproductive technology but lower maternal hypertension, oligohydramnios, chorioamnionitis rates and Clinical Risk Index for Babies scores II without base excess than the singletons. In univariate analysis, multiples had a lower incidence of respiratory distress syndrome, bronchopulmonary dysplasia, and sepsis. The mortality rate was not significantly different for overall gestational ages except for those born at ≤26 weeks of gestation. In multivariate logistic analysis, the incidences of intraventricular hemorrhage (grade ≥3), and retinopathy of prematurity requiring treatment were significantly higher than the singletons.

CONCLUSIONS

Mortality was not significantly different between multiples and singletons according to overall gestational age, except for multiples born at ≤26 weeks. A significant higher risk of intraventricular hemorrhage and retinopathy of prematurity requiring treatment was found in multiples. A new strategy to improve the mortality of immature multiples born at ≤26 weeks of gestation should be developed.

Controversies in treatment practices of the mother-infant dyad at the limit of viability

In the setting of threatened extreme preterm birth, balancing maternal and fetal risks and benefits in order to choose the best available treatment options is of utmost importance. Inconsistency in treatment practices for infants born between 22 and 24 weeks of gestatotional age may account for inter-hospital variation in survival rates with and without impairment. Most importantly, non-biased and accurate information must be presented to the family as soon as extremely preterm birth is suspected, including counseling on morbidities and mortality associated with delivery at the limits of viability. This review will focus on different therapeutic medical and surgical practices available for threatened extremely preterm birth to improve fetal and maternal outcomes while highlighting the importance of patient-centered approaches.

Factors Associated With Maternal and Neonatal Interventions at the Threshold of Viability

OBJECTIVE

To quantify the influence of maternal sociodemographic, medical, and pregnancy characteristics on decisions to offer or receive antepartum and neonatal interventions with deliveries occurring at 22-23 weeks of gestation.

METHODS

This is a case-control study of U.S. live births at 22 0/7-23 6/7 weeks of gestation using National Center for Health Statistics vital statistics birth records from 2012 to 2016. We analyzed three outcomes in the treatment of periviable delivery: 1) maternal interventions (cesarean delivery, maternal hospital transfer or antenatal corticosteroid administration), 2) neonatal interventions (neonatal intensive care unit admission, surfactant administration, antibiotic administration, or assisted ventilation), and 3) combined interventions (at least one maternal and at least one neonatal intervention). Logistic regression estimated the influence of characteristics on interventions received.

RESULTS

Of 19,844,580 U.S. live births from 2012 to 2016, 24,379 (0.12%) occurred at 22-23 weeks of gestation. Of these, 37.5% received maternal interventions, 51.7% received neonatal interventions, and 28.0% received combined interventions. Rates of births receiving at least one intervention were 38.9% and 78.3% for 22 and 23 weeks of gestation, respectively. Preeclampsia was the factor most positively associated with interventions. Other factors positively associated with interventions were increasing maternal age, Medicaid, low educational attainment, multiparity, twin gestation, and infertility treatment. Some factors had opposite influences on maternal compared with neonatal interventions. The presence of birth defects was positively associated with maternal interventions but negatively associated with neonatal interventions, whereas being of black race was negatively associated with maternal interventions but positively associated with neonatal interventions.

CONCLUSION

Maternal and neonatal interventions occur frequently at the threshold of viability, especially at 23 weeks of gestation where the occurrence of interventions exceeds 50%. This study identifies sociodemographic and medical factors associated with using interventions with periviable deliveries. These data elucidate observed practice patterns in the management of periviable births and may assist providers in the counseling of women at risk of periviable birth.

Neurodevelopmental Outcome and Adaptive Behavior in Preterm Multiples and Singletons at 1 and 2 Years of Corrected Age

Background

Recent literature has investigated the role of multiple birth on neurodevelopmental outcomes of premature infants, especially extremely preterm ones. Multiple gestations are often associated to increased neurodevelopmental disability. Actually, research findings are controversial.

Objective

To compare the neurodevelopmental and behavioral outcomes of multiples and singletons in a cohort of preterm infants ≤28 weeks gestational age at 1 and 2 years of corrected age.

Methods

The study included 86 infants, born from January 2014 to September 2017 and enrolled in the follow-up program provided at authors’ Institution. Exclusion criteria included: major brain lesions and malformations, severe neuro-sensorial deficits, genetic syndromes, single-twin survivors. Thirty four multiples were compared to 52 singletons, using the Griffiths Mental Development Scales and the Child Behavior Checklist 1½–5. Statistical analysis was based on ANOVA techniques to test group differences. A p < 0.05 was considered statistically significant.

Results

The neurodevelopmental outcomes of multiples and singletons at 1 and 2 years of corrected age did not significantly differ at a general level (p > 0.05). Multiples showed significantly lower mean scores than singletons at 1 year in Locomotor (87.15 ± 11.94 vs. 92.48 ± 11.59) and Personal-Social (84.88 ± 10.25 vs. 89.63 ± 8.19) subscales. Considering the behavioral outcomes, higher rates of externalizing problems were observed in multiples at 2 years (54.27 ± 9.64 vs. 49.31 ± 10.39).

Conclusion

The slightly lower neurodevelopmental outcome showed by multiples, especially in the gross-motor and personal-social domains at 1 year, might be related to the specific environmental condition they experience. Multiple birth may affect mother’s sensitivity to infant’s needs and infant’s acquisition of emotional and behavioral regulation. This affects the separation process and the acquisition of the independent walking and other gross-motor skills. Being multiples might also induce an hyperstimulation and this could explain their higher vulnerability to externalizing problems (impulsiveness, hyperactivity, attention deficits). Additionally, males are more affected by the multiple condition than females.

Neurodevelopmental outcome of preterm twins at 5 years of age

BACKGROUND

Twins are considered to be at an increased risk for perinatal mortality and morbidities, but it is unclear whether preterm twins are at an increased risk for poor developmental outcomes when compared to preterm singletons. Our aim was to compare the neurodevelopmental outcome of preterm twins vs singletons at 5 years of age.

METHODS

Very low birth weight and very low gestational age infants (twins n = 66, singletons n = 157) were recruited as a part of the PIPARI project in the Turku University Hospital, covering a regional population. Cognitive development, neuropsychological performance, and neurodevelopmental impairments (including cerebral palsy, hearing deficit, visual impairment, and intellectual disability) were evaluated at 5 years of age.

RESULTS

Twins and singletons had otherwise similar perinatal background factors, except for the higher proportion of preterm rupture of membranes in singletons. Twins had cognitive and neuropsychological outcomes that were otherwise comparable with singletons, but they had a slightly lower verbal intelligence quotient (estimate -5.81, 95% CI -11.14 to -0.48, p = 0.03). Being a twin was not a risk for neurodevelopmental impairments.

CONCLUSIONS

Our study shows that, contrary to a common hypothesis, the overall neurodevelopment of very preterm twins does not significantly differ from that of preterm singletons.

Different levels of cardiometabolic indicators in multiple vs. singleton children

BACKGROUND

We aimed to compare cardiometabolic indicators in singletons and multiples at age 7 and explore the birthweight mediation effect.

METHODS

We studied 5431 singletons and 103 sets of multiples from Generation XXI birth cohort. Anthropometric measurements, body composition, and fasting blood samples were obtained. Age- and sex-specific z-scores were calculated (additionally height-specific for blood pressure). Adjusted regression coefficients and respective 95% confidence intervals [β (95%CI)] were computed using path analysis.

RESULTS

Multiples had lower weight [- 0.419 (- 0.616;-0.223)], height [- 0.404 (- 0.594;-0.213)], BMI [- 0.470 (- 0.705;-0.234)], fat mass index [- 0.359 (- 0.565;-0.152)], waist circumference [- 0.342 (- 0.537;-0.147)], and waist-to-height ratio [- 0.165 (- 0.326;-0.003)] z-scores. These results were explained by the indirect effect via birthweight, which was also negative and significant for all the aforementioned cardiometabolic indicators, while no direct effect was present. There were also significant indirect effects regarding fat-free mass index, glucose, insulin, and blood pressure, though the total effects were not significant, due to the balance between direct and indirect effects. The only significant direct effect was regarding diastolic blood pressure [- 0.165 (- 0.302;-0.028)].

CONCLUSIONS

At age 7, multiples presented better cardiometabolic indicators explained by lower weight at birth, except for the lower blood pressure which was independent of an effect via birthweight.

Twin versus singleton pregnancy in women ≥ 45 years of age: comparison of maternal and neonatal outcomes

Objectives: The aim of the study is to compare the effect of very advanced maternal age (≥45 years) on maternal and neonatal outcomes of twin and singleton pregnancies.Materials and methods: This retrospective cohort study included women ≥ 45 years of age who gave birth to twins. Each was randomly matched to two women ≥ 45 years of age who gave birth to singletons within 7 days of the study subject. Data on maternal age, gravidity, parity, background medical information, body mass index at conception, number of fetuses, mode of conception (either spontaneous or assisted reproductive technology [ART]), mode of delivery, and gestational age at delivery were extracted from a real-time computerized database.Results: The data of 75 twin pregnancies of women aged ≥ 45 years were compared with those of 150 singleton pregnancies matched for maternal age. There were significantly more cases of hypertensive complications among the twin pregnancies compared to the singleton pregnancies (41.33 versus 14.00%, respectively, OR = 3.33, 95% CI = 2.26-8.30, p = .000) and more cases of preeclamptic toxemia (29.33 versus 12.00%, respectively, OR = 3.04, 95% CI = 1.51-6.13, p = .001). The duration of twin pregnancies was much shorter compared to singleton pregnancies, with a higher incidence of deliveries prior to 37 weeks' gestation (56.00 versus 8.00%, respectively, OR = 14.64, 95% CI = 6.94-30.85, p = .000), and deliveries prior to 34 weeks' gestation (22.67 versus 2.00%, respectively, OR = 14.36, 95% CI = 4.06-50.86, p = .000). More infants of twin pregnancies had a low birth weight (68.00 versus 10.00%, respectively, OR = 19.13, 95% CI = 10.14-36.06, p = .000), and many had a very low birth weight (10.67 versus 0.67%, respectively, OR = 17.79, 95% CI = 2.33-135.97, p = .000). The infants of twin pregnancies also included more cases of intubation (10.00 versus 0.00%, respectively, p = .000), more cases of hypoglycemia (12.67 versus 5.33%, respectively, OR = 2.57, 95% CI = 1.09-6.08, p = .026), and were admitted much more often to the neonatal intensive care unit (36.00 versus 8.00%, respectively, OR = 6.47, p = .00, CI = 3.29-12.74).Conclusions: Women ≥ 45 years of age with twin pregnancies and their neonates sustain more severe adverse outcome compared to matched pairs of singleton pregnancies. It is recommended that a single embryo transfer should be offered in preference to multiple embryos when those women are undergoing ART.

Temporal trends in the birth rates and perinatal mortality of twins: A population-based study in China

OBJECTIVE

Until now, little was known about the epidemiological characteristics of twins in China due to a lack of reliable national data. In this study, we aimed to analyze temporal trends and perinatal mortality of twins from China.

METHODS

Data on twins between 2007 and 2014 were obtained from the China National Population-Based Birth Defects Surveillance System. Twin and singleton deliveries after at least 28 weeks of gestation were recruited and followed until postnatal day 42. Twinning rates were defined as the number of twin individuals per 1000 births(stillbirths and live births). The Weinberg's differential method was utilized to estimate the number of monozygotic and dizygotic twins.

RESULTS

During 2007-2014, the twinning rate increased by 32.3% from 16.4 to 21.7 per 1000 total births with an average of 18.8‰. Among twins, both the perinatal mortality rate (26.1 per 1000 total births) and neonatal death rate (15.7 per 1000 live births) presented a downward tendency but remained at a high level. Large urban-rural and geographic disparities were identified in twinning rates, in perinatal and neonatal mortality, and in their temporal trends.

CONCLUSIONS

The upward trend of twinning rates in China paired with the relatively high rates of perinatal and neonatal mortality among twins highlights the need for improved perinatal care in the light of socio-demographic differences.

Comparison of different types of twin pregnancies in terms of obstetric and perinatal outcomes: association of vanished twins with methylenetetrahydrofolate reductase (MTHFR) polymorphism(s)

PURPOSE

Vanished twin (VT) has been associated with poor perinatal outcomes. Our research aimed to investigate the outcomes of pregnancies with vanished twin and its possible association with methylenetetrahydrofolate reductase (MTHFR) polymorphisms.

METHODS

This study consisted of 30 of 38 VT pregnancies (group 1, VT group), 109 singletons (group 2), 70 spontaneous twins (group 3), and 101 in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) twins (group 4).

RESULTS

Most patients in group 1 (28/30) were tested for MTHFR genes (C677T or A1298C polymorphisms). Eight of the 38 pregnancies with VT (21.1%) resulted in miscarriage. The prevalence of "2 or more pregnancy losses" in the "obstetric history" in group 1 was higher (23.3%) than those in the other groups (p = 0.007, χ² = 17.8). The allelic frequencies of MTHFR 677 and MTHFR 1298 in group 1 were 0.268 and 0.429, respectively (higher than those in healthy population). The median birthweights in groups 1, 2, 3, and 4 were 2940, 3200, 2300, and 2095 g, respectively. The prevalence of respiratory distress syndrome was significantly higher in the IVF/ICSI twin pregnancy group (p < 0.001, χ² = 21.2). Early pregnancy loss and the presence of "2 or more miscarriages" in the obstetric history of pregnancies with VT were more frequent.

CONCLUSION

The coincidence of VT and MTHFR polymorphisms might play an incidental or factual role in this connection.

Perinatal outcomes after previable preterm premature rupture of membranes before 24 weeks of gestation

OBJECTIVE

A current descriptive assessment of perinatal outcomes in pregnancies complicated by previable preterm premature rupture of membranes (pPPROM) at <24 weeks of gestation, after expectant treatment.

STUDY DESIGN

Maternal and short-term neonatal data were collected for patients with pPPROM.

RESULTS

Seventy-three patients with 93 fetuses were hospitalized with pPPROM at 15-24 weeks' gestation. Among these patients, 27.4% (n=20) chose pregnancy termination, 27.4% (n=20) miscarried and 45.2% (n=33) proceeded to live births. After a median latency period of 38 days, ranging from 1 to 126 days, 24 singletons and 20 multiples were live-born, of whom 79.5% (n=35) survived the perinatal period. The main neonatal sequelae were pulmonary hypoplasia (29.5%; n=13), connatal infection (56.8%; n=25), intraventricular hemorrhage (25%; n=11; resulting in five neonatal deaths) and Potter's syndrome (15.9%; n=7). Nine newborns died, within an average of 2.8 days (range, 1-10 days). The overall neonatal survival rate was 51.5% - including miscarriages but not elective terminations. The intact survival rate was 45.5% of all live-born neonates.

CONCLUSIONS

Even with limited treatment options, overall neonatal survival is increasing. However, neonatal mortality and morbidity rates remain high. The gestational age at membrane rupture does not predict neonatal outcome.

Outcome of Twin Pregnancies Complicated by a Neural Tube Defect

Twin pregnancies discordant for neural tube defects (NTD) is a management dilemma. Risks of preterm delivery from polyhydramnios must be balanced with the risks of selective termination (ST) of the anomalous fetus. We investigated the prevalence of twin pregnancies discordant for NTD and the rate of pregnancy complications in our institution over a 10-year period. Cases were obtained by searching the hospital ultrasound database and findings were confirmed by expert review of ultrasound images. Outcomes of ST and expectant management were assessed. Each unaffected co-twin was assigned to three consecutive twin pregnancy controls matched by chorionicity and maternal age. Primary outcome was birth before 34 weeks' gestation. Secondary outcomes were small for gestational age, mode of delivery, neonatal unit admission, and neonatal death. In total, 13 pregnancies were identified as potential cases. Of these, 11 were included in the analysis: 9 dichorionic diamniotic and 2 monochorionic diamniotic twins. Seven cases had ST and four were managed expectantly. We found 100% (4/4) of expectantly managed pregnancies delivered <34 weeks compared with 14% (1/7) of the ST group (p = .015). Polyhydramnios complicated three expectantly managed pregnancies and one pregnancy in the ST group. The birthweight SD score of all unaffected co-twins was ≥-2. The case-control analysis showed a higher rate of polyhydramnios in twin pregnancies discordant for NTD compared with controls, but little evidence for differences between groups in delivery rates <34 weeks, birthweight, neonatal unit admission, or neonatal death. ST warrants serious consideration to avoid potential complications to the unaffected co-twin.

Neurodevelopmental Outcomes of Twins Compared With Singleton Children: A Systematic Review

More than 200 million children aged <5 years fail to reach their full cognitive potential, and children born as twins are particularly at risk. In this article, we review studies that examined differences in the neurodevelopmental outcomes of twins compared to singletons. We searched the Medline database for articles on twins, singletons, neuro, and cognitive development. We also inspected bibliographies of relevant publications to identify related articles from 2011 to 2017. Our search criteria yielded 162 studies, 8 of which met the inclusion criteria. Of the eight studies examined, four were prospective follow-up studies, three were cross-sectional studies, and one was a randomized controlled trial. Five of these studies were carried out in developed countries, and they found no statistically significant difference in neurodevelopmental outcomes among twins and singletons. However, two of the three studies carried out in developing countries found a difference with singletons having significantly higher academic ratings than twins. Studies in which neurodevelopmental outcomes were measured early in life (1-5 years) showed no significant twin-singleton differences, while those in which it was measured later in life showed mixed twin-singleton differences. Overall, these studies may have been underpowered and may not have been optimally designed and implemented. There is need for studies with adequate sample sizes, good design, and optimal measurement of all relevant covariates in order to resolve the conflicting reports in the literature.

Morbidity and mortality of very low birth weight multiples compared with singletons

BACKGROUND

Previous studies comparing the neonatal outcome of very low birth weight (VLBW) multiples and singletons have suggested a worse outcome for multiples at gestational ages on the limits of viability.

OBJECTIVES

The objective of this study is to determine the neonatal mortality and morbidity of VLBW multiples compared to singletons.

METHODS

This is a retrospective study including all infants registered in the Spanish network for infants under 1500 g (SEN1500), over a 12-year period (from 2002 to 2013). Mortality and major morbidities were compared between singletons and multiples.

RESULTS

About 32,770 infants were included: 21,123 singletons (64.5%) and 11,647 multiples (35.5%), with a mean gestational age of 29.5 weeks (22-38), and mean birth weight of 1115 g (340-1500). When adjusted by other perinatal factors, multiple pregnancy has a significantly higher risk of mortality than singleton pregnancy (odds ratio (OR) 1.15; IC 95% 1.05-1.26, p = .002), but not a higher risk of major morbidity or composite adverse outcome. In the subgroup of infants born before 26 weeks, multiples showed a higher risk of mortality (63.9% versus 51%, OR 1.7; 95% CI 1.47-1.96) and a higher risk of composite adverse outcome (88.9% versus 81.5%, OR 1.82, 95% CI 1.28-2.24).

CONCLUSIONS

In preterm infants born with less than 1500 g, multiple pregnancy is a prognostic factor that can slightly increase mortality. Extremely preterm infants born before 26 weeks have a greater risk of mortality and major morbidity if they come from a multiple pregnancy.

Epidemiology of Periviable Births: The Impact and Neonatal Outcomes of Twin Pregnancy

This article discusses a study that estimated the prevalence of twin live births in the United States that were delivered in the periviable (20-25 weeks) gestational age, and compared changes in twin neonatal mortality and morbidity rates between 2005 and 2013 overall, and at periviable gestations. Although the decline in twin neonatal mortality rates at 23 and 24 weeks is encouraging, and suggests advancement in the neonatal care of these extremely small twins, the concomitant increase in neonatal morbidity at 23 weeks is concerning. Efforts to understand if twins delivered at periviable gestations suffer from long-term consequences of neurodevelopmental and cognitive deficits remain important.

Risk factors for brain damage among preterm twins

AIM

To evaluate the perinatal and postnatal risk factors for various brain pathologies among preterm twins.

METHODS

Retrospective data of 104 twin pairs of which one of the siblings had evidence of abnormal head ultrasound (HUS) and its co-twin with normal HUS served as control.

RESULTS

Abnormal HUS consisted of periventricular echodensities among 69 infants, intraventricular hemorrhage among 28 infants, cystic periventricular leukomalacia among 10 infants, and other parenchymal brain pathologies among 5 infants. Perinatal and postnatal complications were similar between study and controls. Siblings with severe brain pathologies were ventilated for longer time over their co-twins. In 10 out of 11 cases of discordant twins (≥20%) with severe brain pathology, the severe pathology was recorded in the larger sibling.

CONCLUSIONS

Our study results, which included matched preterm twin pairs for study/control groups to evaluate risk factors for the overall evidence of brain injury, could not determine specific risk factors for these brain pathologies. The finding that severe brain pathologies were more common among the larger co-twin requires further study of and attention to short- and long-term outcomes and the potential conflicts that may arise.

Neonatal morbidities and need for intervention in twins and singletons born at 34-35 weeks of gestation

OBJECTIVE

To compare indications for delivery and neonatal morbidities between twins and singletons born between 34 and 35 weeks of gestation.

STUDY DESIGN

A prospective observational study was performed in which all infants born between January and August 2008, at Sheba Medical Center at 34 0/7-35 6/7 weeks of gestational age were included. Indications for delivery, infants' morbidities and medical interventions were documented. Twins and singletons were compared for antenatal maternal characteristics, risks of short-term neonatal complications and interventions.

RESULTS

One hundred and seventy-three mothers and 229 neonates (114 twins and 115 singletons) were included. Background maternal characteristics as well as the use of antenatal steroids and MgSO4 were similar between the groups. Only 44% of all deliveries were spontaneous, while the rest were indicated deliveries. Twins were born lighter and 31.9% of them were SGA. Nevertheless, singletons were significantly more likely to receive medical interventions such as prolonged oxygen use (>1 day) and phototherapy. All late preterm infants (n=5) needing surfactant administration were singletons. Overall, the risk of needing any medical intervention was significantly higher for singletons compared with twins (OR 1.8, 95% CI 1.02-3.2).

CONCLUSIONS

A significant proportion of late preterm births is iatrogenic. Twins and singletons are dissimilar with regards to risks of short-term complications. Despite being born smaller and more SGA, twins are at lower risk of requiring medical intervention in the immediate neonatal period compared with singletons.

Pregestational diabetes is associated with adverse outcomes in twin pregnancies: a regional register-based study

INTRODUCTION

The incidence of pregnancies complicated by twinning and diabetes is increasing in the UK. This is a worrying trend as both diabetes and twin gestations are associated with a high risk of adverse pregnancy outcomes. The few studies that have specifically addressed how twinning and pregestational diabetes in the same pregnancy may affect outcome have reported conflicting results.

MATERIAL AND METHODS

We analyzed data on 27 women with a twin pregnancy and pregestational diabetes (54 babies) and 6407 women with a twin pregnancy without diabetes (12 814 babies) from the Northern Survey of Twin and Multiple Pregnancy during 1998-2010. A composite adverse pregnancy outcome (comprising fetal loss before 24 weeks, termination of pregnancy, stillbirth, infant death or any major congenital anomaly), extended perinatal mortality (stillbirths and neonatal deaths) and major congenital anomaly were the main outcome measures. Adjusted rate ratios were estimated using generalized estimating equations for Poisson regression controlling for potential confounders.

RESULTS

Mothers with twin pregnancies with diabetes were older (p = 0.001) and had higher body mass indices (p < 0.0001) than those without diabetes. Their twins were more likely to be delivered earlier (p = 0.026), be delivered by cesarean section (80.4% vs. 49.7%; p < 0.0001), be large-for-gestational-age (p < 0.0001) and require admission to a special care baby unit (p < 0.0001). Pregestational diabetes was associated with significantly increased rates of the composite adverse outcome and major congenital anomalies in twins (adjusted rate ratios 2.66, 95% confidence interval 1.14-6.20 and adjusted rate ratios 3.51, 95% confidence interval 1.31-9.40, respectively).

CONCLUSION

Maternal pregestational diabetes in twin pregnancies is associated with a significantly increased risk of an adverse pregnancy outcome.

Neurodevelopmental outcomes of preterm singletons, twins and higher-order gestations: a population-based cohort study

OBJECTIVE

To study the neurodevelopmental outcomes of multiple (twins, triplets, quads) compared with singleton extremely preterm infants <29 weeks gestation.

DESIGN

Population-based retrospective cohort study.

SETTING

A network of 10 neonatal intensive care units in a geographically defined area of New South Wales and the Australian Capital territory.

PATIENTS

1473 infants <29 weeks gestation born between 1 January 1998 and 31 December 2004.

INTERVENTION

At 2-3 years of corrected age, a neurodevelopmental assessment was conducted using either the Griffiths Mental Developmental Scales or the Bayley Scales of Infant Development II.

MAIN OUTCOME MEASURE

Moderate-severe functional disability was defined as developmental delay (Griffiths Mental Developmental Scales General Quotient or Bayley Scales of Infant Development-II Mental Development Index >2 SDs below the mean), moderate cerebral palsy (unable to walk without aids), sensorineural or conductive deafness (requiring amplification) or bilateral blindness (visual acuity <6/60 in the better eye).

RESULTS

Of the 1081 singletons and 392 multiples followed-up, singletons demonstrated higher rates of systemic infections, steroid treatment for chronic lung disease and birth weight <10th percentile. Moderate-severe functional disability did not differ significantly between singletons and multiples (15.8% vs 17.6%, OR 1.14; 95% CI 0.84 to 1.54; p=0.464). Further subgroup analysis of twins, higher-order gestations, 1st-born multiples, 2nd or higher-born multiples, same and unlike gender multiples, did not demonstrate statistically higher rates of functional disability compared with singletons.

CONCLUSIONS

Premature infants from multiple gestation pregnancies appear to have comparable neurodevelopmental outcomes to singletons.

Trends in the prevalence, risk and pregnancy outcome of multiple births with congenital anomaly: a registry-based study in 14 European countries 1984-2007

OBJECTIVE

To assess the public health consequences of the rise in multiple births with respect to congenital anomalies.

DESIGN

Descriptive epidemiological analysis of data from population-based congenital anomaly registries.

SETTING

Fourteen European countries.

POPULATION

A total of 5.4 million births 1984-2007, of which 3% were multiple births.

METHODS

Cases of congenital anomaly included live births, fetal deaths from 20 weeks of gestation and terminations of pregnancy for fetal anomaly.

MAIN OUTCOME MEASURES

Prevalence rates per 10,000 births and relative risk of congenital anomaly in multiple versus singleton births (1984-2007); proportion prenatally diagnosed, proportion by pregnancy outcome (2000-07). Proportion of pairs where both co-twins were cases.

RESULTS

Prevalence of congenital anomalies from multiple births increased from 5.9 (1984-87) to 10.7 per 10,000 births (2004-07). Relative risk of nonchromosomal anomaly in multiple births was 1.35 (95% CI 1.31-1.39), increasing over time, and of chromosomal anomalies was 0.72 (95% CI 0.65-0.80), decreasing over time. In 11.4% of affected twin pairs both babies had congenital anomalies (2000-07). The prenatal diagnosis rate was similar for multiple and singleton pregnancies. Cases from multiple pregnancies were less likely to be terminations of pregnancy for fetal anomaly, odds ratio 0.41 (95% CI 0.35-0.48) and more likely to be stillbirths and neonatal deaths.

CONCLUSIONS

The increase in babies who are both from a multiple pregnancy and affected by a congenital anomaly has implications for prenatal and postnatal service provision. The contribution of assisted reproductive technologies to the increase in risk needs further research. The deficit of chromosomal anomalies among multiple births has relevance for prenatal risk counselling.