Lightening is when the baby drops deep to the pelvis.  It is also known as engagement because the baby’s head engages the pelvic opening. When the baby settles deep into the pelvis, it reduces some of the  pressure on the diaphragm and relieve shortness of breath. This may also mean that there is increased pressure on your bladder and therefore increased bathroom trips.
 

 
The baby drops sometime during the last stages of labor. For new moms , this is usually within 2 weeks to delivery. However in some cases, the baby may drop as early as 4 weeks to delivery.  For second time mothers, lightening may not occur until labor has begun. This is because the pelvic muscles have already been stretched. Lightening will make you feel and look different.

Changes that may occur during lightening

 
Breathe better : Breathing becomes easy as the baby settles deep into the pelvis. This is because as the baby drops, it relieves some pressure on the diaphragm making it easier to take deep breaths .

Frequent urination : When the baby drops, it increases the pressure on the bladder. Even though frequent urination is common during pregnancy, lightening increases the number of trips to the bathroom even more.

Increased appetite :As the baby drops during pregnancy, it puts pressure on organs of the body including the stomach. This makes it difficult for a pregnant women to eat a full meal. When lightening occurs, pressure on the stomach is drastically reduced. It also reduces the frequency  of heartburn.

Change in abdomen : Lightening causes the stomach to hang lower than it did before. When sitting , it may feel as if the baby is resting on your lap.