Twin gestation and the burden of adult cardio-renal disease.

The rate of twin births has increased by nearly 80% in recent decades largely due to advanced reproductive technologies. Twins are often born preterm and/or growth restricted which are independently associated with impaired renal and vascular development. Many preterm and twin infants are surviving into adulthood, albeit with an increased burden of chronic health conditions. Twinning as a research tool offers the unique opportunity to investigate the impact of genetics versus the environment on clinical outcomes. This educational review will focus on delineating our current understanding of the renal and cardiovascular development and long-term outcomes among twin born individuals. Specifically, existing literature regarding how twins differ in kidney size and function as well as vascular stiffness and hypertension profiles from singletons will be discussed. The unique situation of twin-twin transfusion syndrome which is associated with distinct short- and long-term cardio-renal disease will be highlighted. Ultimately, the ability to stratify risk of future cardio-renal disease at birth for infants born preterm and/or growth restricted, including twins, is important to guide clinical follow up. In addition, this early risk stratification could direct research efforts to better understand the mechanisms driving impaired organogenesis and allow for discovery of therapeutic interventions aimed at modifying disease progression and improving longevity in the most vulnerable infant subgroups.