Twins and cerebral palsy

Associations of Assisted Reproductive Technology and Twin Pregnancy With Risk of Congenital Heart Defects

IMPORTANCE

The extent to which assisted reproductive technology is associated with increased risk of congenital heart defects independent of its known association with twinning remains uncertain.

OBJECTIVE

To assess the extent to which assisted pregnancy is associated with increased risk of congenital heart defects independent of its known association with twinning.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study linked records of congenital heart defect diagnoses with assisted reproductive technology cycles in 507 390 singleton or twin pregnancies (10 149 assisted pregnancies and 497 241 nonassisted pregnancies), including singleton and twin early pregnancy losses, stillbirths, and live births (follow-up to 1 year of age) in Ontario, Canada, between April 1, 2012, and October 31, 2015. Statistical analysis was performed from January 1, 2017, to September 9, 2019.

EXPOSURES

Assisted reproductive technology and its 2 subtypes: intracytoplasmic sperm injection and in vitro fertilization without intracytoplasmic sperm injection.

MAIN OUTCOMES AND MEASURES

The main outcome was congenital heart defects (prevalence and relative risk measured as odds ratios [ORs]). Mediation analysis was performed to assess the extent to which the association between assisted reproductive technology and congenital heart defects was mediated by twinning.

RESULTS

Of 507 390 mother-infant pairs with singleton or twin pregnancies evaluated, the prevalence of congenital heart defects in assisted pregnancies (223 [2.2%]) was higher than that in nonassisted pregnancies (6057 [1.2%]; crude OR, 1.82; 95% CI, 1.59-2.09). The strength of the association between assisted pregnancy and congenital heart defects decreased after adjusting for several risk factors simultaneously (adjusted OR, 1.70; 95% CI, 1.48-1.95). Further mediation analysis indicated that most of the association between assisted pregnancy and congenital heart defects was mediated by twinning (adjusted OR, 1.68; 95% CI, 1.44-1.92), and the natural direct association of assisted pregnancy with congenital heart defects among singleton pregnancies was 1.09 (95% CI, 0.93-1.25). Mediation of twinning accounted for 87.3% of the association.

CONCLUSIONS AND RELEVANCE

Our study results suggest that the association between assisted reproductive technology and congenital heart defects may be mediated by twinning.

Effectiveness of timing strategies for delivery of monochorionic diamniotic twins

OBJECTIVE

The purpose of this study was to compare strategies for delivery timing of uncomplicated monochorionic diamniotic twin pregnancies.

STUDY DESIGN

A decision tree compared 9 strategies that included scheduled delivery between 32 and 38 weeks' gestation, with or without confirmation of fetal lung maturity. Outcomes in the model included fetal death, infant death, respiratory distress syndrome, mental retardation, and cerebral palsy.

RESULTS

A scheduled delivery at 38 weeks' gestation was the preferred strategy, which resulted in the highest quality adjusted life years under base-case assumptions. Decreased, but comparable, quality adjusted life years estimates resulted from scheduled deliveries at 36 and 37 weeks' gestation, with or without amniocentesis. Sensitivity analyses demonstrated that the optimal gestational age for delivery was always ≥36 weeks' gestation.

CONCLUSION

This decision analysis suggests that, for women with uncomplicated monochorionic twins, delivery between 36 and 38 weeks' gestation is the preferred strategy for timing of delivery.

Cerebral palsy secondary to perinatal ischemic stroke

Congenital hemiplegia is the most common form of cerebral palsy in children born at term, and stroke is the number one cause. Neonatal ischemic stroke includes perinatal arterial ischemic stroke, presumed pre- or perinatal stroke, and cerebral sinovenous thrombosis, all of which have emerged as important contributors to cerebral palsy. Of increasing interest is how the overlapping list of associations and risks for stroke and cerebral palsy relate to each other. Stroke-induced injury is focal, and the preservation of normal areas of brain may afford unique opportunities for plastic adaptation. The implications of this essential difference are stressed in a discussion of how the epidemiology, pathophysiology, diagnosis, and therapeutic advancements in perinatal stroke relate to the outcome of cerebral palsy.

High risk of unexpected late fetal death in monochorionic twins despite intensive ultrasound surveillance: a cohort study

BACKGROUND

The rationale for fetal surveillance in monochorionic twin pregnancies is timely intervention to prevent the increased fetal/perinatal morbidity and mortality attributed to twin-twin transfusion syndrome and intrauterine growth restriction. We investigated the residual risk of fetal death after viability in otherwise uncomplicated monochorionic diamniotic twin pregnancies.

METHODS AND FINDINGS

We searched an electronic database of 480 completed monochorionic pregnancies that underwent fortnightly ultrasound surveillance in our tertiary referral fetal medicine service between 1992 and 2004. After excluding pregnancies with twin-twin transfusion syndrome, growth restriction, structural abnormalities, or twin reversed arterial perfusion sequence, and monoamniotic and high-order multiple pregnancies, we identified 151 uncomplicated monochorionic diamniotic twin pregnancies with normal growth, normal liquor volume, and normal Doppler studies on fortnightly ultrasound scans. Ten unexpected intrauterine deaths occurred in seven (4.6%) of 151 previously uncomplicated monochorionic diamniotic pregnancies, within 2 wk of a normal scan, at a median gestational age of 34(+1) wk (weeks(+days); range 28(+0) to 36(+3)). Two of the five cases that underwent autopsy had features suggestive of acute late onset twin-twin transfusion syndrome, but no antenatal indicators of transfusional imbalance or growth restriction, either empirically or in a 1:3 gestation-matched case-control comparison. The prospective risk of unexpected antepartum stillbirth after 32 wk was 1/23 monochorionic diamniotic pregnancies (95% confidence interval 1/11 to 1/63).

CONCLUSION

Despite intensive fetal surveillance, structurally normal monochorionic diamniotic twin pregnancies without TTTS or IUGR are complicated by a high rate of unexpected intrauterine death. This prospective risk of fetal death in otherwise uncomplicated monochorionic diamniotic pregnancies after 32 wk of gestation might be obviated by a policy of elective preterm delivery, which now warrants evaluation.

Preterm twin gestation and cystic periventricular leucomalacia

OBJECTIVE

To identify risk factors for the development of cystic periventricular leucomalacia (PVL) in twin gestation.

DESIGN

Retrospective case-control study.

SETTING

Tertiary care university hospital, Department of Paediatrics, Division of Neonatology, Graz, Austria.

PATIENTS

Preterm twin gestations with one sibling having developed cystic PVL, diagnosed by ultrasound scans, compared with their co-twins without PVL, in hospital between 1988 and 2000.

MAIN OUTCOME MEASURES

Perinatal and postnatal risk factors for the development of PVL.

RESULTS

Eighteen preterm twin gestations were included. Monochorionicity was evident in 47% of the pregnancies, and twin to twin transfusion syndrome occurred in two cases (11%). Fetal distress correlated inversely with PVL (15% v 53%, p = 0.019, relative risk (RR) = 2.057, 95% confidence interval (CI) = 1.067 to 3.968). Hypocarbia with Pco(2) levels below 30 mm Hg (4 kPa) was diagnosed in 29% of the cases compared with 6% of the controls (p = 0.038, RR = 1.944, 95% CI = 1.113 to 3.396). There were no significant differences between groups with regard to premature rupture of the membranes, early onset infection, respiratory distress syndrome, mechanical ventilation, arterial hypotension, persistent ductus arteriosus, and hyperbilirubinaemia. Asphyxia was only evident in three controls. Three infants died and another three were lost to follow up. None of the cases compared with 62% of the controls were diagnosed as having developed normally (p < 0.001), and 14 cases (82%) compared with two controls (15%) developed cerebral palsy (p < 0.001).

CONCLUSION

Hypocarbia was the only risk factor strongly associated with cystic PVL. The general outcome of the infants was poor.

The epidemiology of sudden infant death syndrome

BACKGROUND

Twins compared to singletons are at increased risk of sudden infant death syndrome (SIDS).

AIMS

To compare the epidemiology of SIDS in twins and singletons and to test the hypothesis that monozygous (MZ) were at greater risk of SIDS than dizygous (DZ) twins.

METHODS

Data from the Office for National Statistics on all registered live births and infant deaths with registered cause of death "sudden unexpected death in infancy" in England and Wales from 1993 to 1998 were obtained, together with the registered birth weight and, for twins, whether they were of like or unlike sex.

RESULTS

The crude relative risk of SIDS in twins is twice that in singletons. There has been a significant temporal decline in SIDS mortality. There is also a significant increase in risk with decreasing birth weight for both twins and singletons. The birth weight specific risk of SIDS in all except for those > or =3000 g is greater in singletons than in twins. There is no significant difference in risk of SIDS in like compared with unlike sex twins.

CONCLUSIONS

In spite of a lower risk of SIDS in twins compared with singletons for each birth weight group <3000 g, one component of the higher crude relative risk of SIDS in twins is attributable to the higher proportion of twins that are of low birth weight. A second component is the higher risk in twins compared with singletons for those of birth weight > or =3000 g. Like sex are at no greater risk than unlike sex twins, which suggests that zygosity is not a significant factor in SIDS.

The epidemiology of cerebral palsy in term infants

Half of cerebral palsy (CP) arises in infants of normal birthweight; yet, many fewer studies seek to identify risk factors for CP in term and near-term infants than in those born very prematurely. There has been no net decrease in the prevalence of CP in term and near-term infants over recent decades. Potentially asphyxiating birth complications account for a small minority of CP cases. Recent studies suggest that disorders of coagulation and intrauterine exposure to infection or inflammation are associated with risk of CP, and that both can be accompanied by signs of neonatal encephalopathy, the best available predictor of CP in term neonates. Therapeutic interventions directed at preventing interruption of oxygen supply have not been shown to reduce the occurrence of CP. There have not yet been studies examining whether medical interventions directed at infection or coagulation disorder can reduce the frequency of CP.