There are many, many new moons and full moons that do not result in eclipses. Why is that?

it is because the sun , moon and earth don't stay in a single line on every new moon and full moon night

what's the question ?

the level of progesterone is low at the pre-ovulatory phase of the cycle but it gradually increases and the levels are high at the luteal phase. if pregnancy occurs, the level of progesterone will be high throughout the pregnancy.

if egg is fertilized and the mother gets pregnant, progesterone starts preparing the uterus for the implantation. it starts building up the lining of uterus and make it hostile of the period of pregnancy.