Early Human Growth

Abstract

Adverse birth outcomes, such as intrauterine growth restriction, preterm birth and congenital malformations, are major contributors to short and long term morbidity and mortality. From the late eighties of the last century, evidence is accumulating that the course and outcome of pregnancy is not only important for the health of the mother and child, but can also be considered a predictor of future health and disease. A mismatch between pre- and postnatal life can increase the vulnerability of the development of non-communicable diseases. This insight led to the Development Origins of Health and Disease (DOHaD) hypothesis, which states that prenatal insults and especially a suboptimal intrauterine environment can result in endocrine and metabolic adaptations in the fetus (reprogramming). Although these adaptations are beneficial to the fetus at first, this eventually could lead to increased risks of non-communicable diseases in adulthood. Most pregnancy complications originate in the periconceptional period and first trimester growth restriction has been related to an increased risk of adverse birth outcomes, including being born SGA. The periconceptional period has been defined based on biological mechanisms as a time span of 14 weeks before conception up to ten weeks after conception. Until recently, epidemiological research has largely neglected the periconceptional period by focusing on fetal size and growth trajectories in the second half of pregnancy and on pregnancy outcome. These outcomes however, are largely influenced by first trimester size and growth trajectories making this an especially vulnerable period in life. Therefore, future research and clinical care will be gradually shifted towards the periconceptional period.