What is the name of the given structure?

Progesterone

The correct answer is option 4. Progesterone.

Progesterone also plays a crucial role during pregnancy, but its effects are more prominent in preparing the body for childbirth and maintaining a healthy pregnancy rather than during the birthing process itself.

Progesterone is known as the "pregnancy hormone" for a reason. Throughout pregnancy, it acts to:

Thicken the uterine lining to create a nurturing environment for the fertilized egg to implant and grow.

Suppress uterine contractions to prevent premature labor.

Increase blood flow to the uterus to nourish the developing baby.

Stimulate the development of breast tissue for milk production.

As childbirth approaches, progesterone levels naturally begin to decline. This decline plays a part in signaling the body that it's time to initiate labor. Oxytocin then takes over as the dominant hormone during childbirth.