What factor is primarily responsible for fetal growth?

The factor primarily responsible for fetal growth is insulin and its insulin-like growth factors. During pregnancy, insulin plays a crucial role in facilitating the uptake of glucose and amino acids in both the mother and fetus, which are vital for the growth and development of fetal tissues. Insulin-like growth factors (IGFs), primarily IGF-1 and IGF-2, are also important mediators in fetal growth, promoting cellular proliferation and differentiation.

These factors work in conjunction with growth hormone and other placental hormones to create a conducive environment for fetal development, influencing not only the size of the fetus but also its overall health and metabolic status. The secretion of these growth factors increases significantly during pregnancy, highlighting their importance in supporting the demands of a growing fetus. Thus, insulin and its insulin-like growth factors are integral to the complex physiological processes that regulate fetal growth.