Long-term Effects of selective fetal growth restriction in MONochorionic twins

Selective fetal growth restriction (sFGR) in monochorionic (MC) twin pregnancies is characterized by a large intertwin growth discrepancy due to unequal placental sharing. Neonatal morbidity and mortality associated with sFGR have been thoroughly described, but data on long-term outcomes is lacking although we know that fetal growth restriction (FGR) in singletons has been associated with an increased risk of neurodevelopmental impairment (NDI), cardiovascular disease (CVD), impaired lung function and suboptimal growth later in life. Knowledge of long-term outcomes is essential both for adequate counselling of parents of these vulnerable patients and for early identification of children who will benefit from additional postnatal monitoring. Moreover, a better understanding of long-term outcome might aid in devising feasible management options in the future.Therefore, insight into long-term outcomes is crucial in providing the highest standard of care for MC twins with sFGR. The results of this study will be complementary to the Twinlife study (NL67331.058.18) which is already ongoing at the LUMC.

The main objective is to assess long-term neurodevelopmental, cardiovascular, pulmonary, and growth outcomes in a cohort of MC twins with sFGR and to compare outcomes within sFGR twin pairs. The study population consists of all MC twin pairs with sFGR born in the LUMC between 2002 and 2017. We defined sFGR as a birth weight discordance (BWD) ≥ 20%.

To assess long-term neurodevelopmental outcome, cognitive and motor development will be evaluated using standardized psychometric age-appropriate tests and a neurological examination. Echocardiography will be used to assess differences in structural cardiac measures and cardiac function, including aortic pulse-wave velocity (aPWV) and carotid intima-media thickness (cIMT). Spirometry will be recorded in children ≥ 4 years old to quantify lung function, including forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and forced mid-expiratory flow rate (FEF(25%-75%). Growth will be assessed using available childhood growth curves from the primary care system and by detailed anthropometric measurements.

The growth-restricted twin will have an increased risk of neurodevelopmental impairment, cardiovascular disease, impaired lung function and suboptimal growth later in life as opposed to its appropriately-grown co-twin.

Parents and children are asked to fill in part of questionnaires at home prior to the follow-up examinations. Two examinations will be scheduled, one for the for the neurodevelopmental assessment, growth measurements and the buccal swab and one for the echocardiography and spirometry.