At a Glance Why Get Tested? When to Get Tested? At specific
times during a woman's menstrual cycle to determine whether/when
she is ovulating; during early pregnancy when symptoms suggest
an ectopic or failing pregnancy; throughout pregnancy to help
determine placenta and fetal health; and when a woman has
abnormal uterine bleeding A blood sample drawn from a vein in
your arm; a limited number of laboratories can perform this test
on saliva. Test Preparation Needed? The Test Sample What is
being tested? This test measures the level of progesterone in
the blood. Progesterone is a steroid hormone whose main role is
to help prepare a woman's body for pregnancy; it works in
conjunction with several other female hormones. On a monthly
basis, the hormone estrogen causes the lining of the uterus, the
endometrium, to grow and replenish itself, while a surge in
luteinizing hormone (LH) leads to the release of an egg from one
of two ovaries. A corpus luteum then forms in the ovary at the
site where the egg was released