There are several signs that may indicate labor is about to begin, including lightening, nesting, effacement and dilation, bloody show, rupture of membranes, and finally consistent contractions.
Near the end of your pregnancy, your baby will settle down deeper into your pelvis. This is known as lightening. Once the baby has lightened, you will notice there is less pressure on your lungs and you are able to breathe better. For many women, lightening occurs as much as a couple of weeks prior to labor, but for others it may occur just before labor begins.
For most of the pregnancy you have probably been fighting the urge to take a nap, so you’ll know when you experience "nesting." One day you will wake up feeling full of energy! You’ll start making hundreds of list of things to do, things to clean, things to buy and everything you’ve put off doing will become a high priority.
Dilation and effacement refer to the preparation of the cervix for birth. The cervix will thin or "ripen" and it will open. This ripening is called effacement and the opening is called dilation. These can only be observed through a vaginal exam.
A thick plug of mucus blocks the cervical opening during pregnancy to prevent bacteria from entering the uterus. When your cervix begins to thin and open, this plug will likely be discharged. You may notice a thick discharge or stringy mucus, typically brown and sometimes tinged with blood. Losing the mucus plug is a sign that labor may begin soon, but it’s not a guarantee. Labor may still be a week or more away.
The amniotic sac is a membrane filled with fluid that cushions your baby in the uterus. Often this membrane will rupture and leak or break just before labor begins. This is often referred to as your "water breaking." If this happens, you may notice a trickle of fluid or a more obvious gush. If your water breaks, or if you believe your water may have broken, consult your doctor right away. He or she will evaluate you and your baby to determine the next steps.
Finally, consistent regular contractions are a good sign you are going into labor. It can be difficult to distinguish these from "braxton-hicks" or "false labor." True labor contractions are regular, follow a predictable pattern (such as every eight minutes), become progressively closer, last progressively longer and become progressively stronger. Each contraction is felt starting in the lower back and then radiating around to the front or visa versa.