Which hormone is least associated with fetal growth?

Human Growth Hormone (hGH) is primarily associated with growth and development in childhood, largely acting through mediating insulin-like growth factor (IGF) production. In fetal growth, while hGH plays a role, it is not as significant as the other hormones listed.

Insulin-like Growth Factor (IGF) is crucial for fetal development as it directly stimulates cellular growth and has numerous actions that support the creation and expansion of tissues. Estrogen also plays a significant role in pregnancy, contributing to the regulation of various processes, including uterine growth, increasing blood flow to tissues, and impacting fetal organ systems. Cortisol, although commonly recognized for its role in stress response, also influences fetal development, particularly in the maturation of organ systems, including the lungs.

In contrast, hGH's effect is less direct when it comes to fetal growth compared to the other hormones in this question. Thus, its association with fetal growth is the weakest among the options listed. This understanding highlights the specific roles that various hormones play during pregnancy and fetal development, underlining the importance of IGF, estrogen, and cortisol in fostering appropriate growth and maturation in the fetus.