Answer
The function of hCG is to support the corpus luteum so it keeps producing two hormones that the placenta can not produce itself, estrogen and progesterone. When the placenta is developed enough to produce these hormones independently, the presence of hCG decrease.. Which is why it is not needed after the first trimester because the placenta is developed enough to produce it on its own.
Work Step by Step
The function of hCG is to support the corpus luteum so it keeps producing two hormones that the placenta can not produce itself, estrogen and progesterone. When the placenta is developed enough to produce these hormones independently, the presence of hCG decrease.. Which is why it is not needed after the first trimester because the placenta is developed enough to produce it on its own.
