What does the term "lightening" refer to in pregnancy?

The term "lightening" refers specifically to the descent of the fetus into the pelvic cavity before labor begins. This physiological process typically occurs in the later stages of pregnancy, usually a few weeks before delivery. As the fetus drops into the pelvis, it can lead to several changes for the pregnant person, including increased pelvic pressure and potentially relief from pressure on the diaphragm, which may make breathing easier.

This descent helps prepare the body for labor by positioning the fetus appropriately for delivery. In many cases, this process is accompanied by other signs of impending labor, but lightening itself specifically pertains to the positioning of the fetus rather than the onset of labor or contractions.

The other options do not accurately define the term "lightening." While increased fetal movements, the onset of contractions, and cervical dilation are all relevant to the labor process, they represent different aspects of labor readiness rather than the specific phenomenon of lightening.