Babies go toward the birth canal shortly before birth, which should be around a woman's due date, according to Women's Health. It's hard to say exactly when this will take place, but there are some signs that show labor is approaching.
A baby drops soon before birth, so it should be close to the due date. There is no exact time frame for a child to be born, so it's hard to say in advance, but there are symptoms of labor that can be tracked.
According to Women's Health, when the baby drops into the lower pelvis, it's called lightening. At this point, the body is preparing itself to give birth. Women may also go through a phase called "nesting," in which they clean, cook, and otherwise prepare for the child that is on its way.
Contractions, lower back pain and cramping that doesn't go away can signify that labor is on the way. Bloody or brownish mucus discharge could be the mucus plug discharging from your body; this means that the cervix is dilating, and the baby should be on its way into the birth canal shortly. When the water breaks, this is also a sign that labor is happening or about to start. Babies enter the birth canal when ready to be birthed, so it typically occurs near the end of labor.