Labor is the process by which the fetus and the placenta leave the uterus. Delivery can occur in two ways, vaginally or by a cesarean delivery.
Labor occurs in three stages and can begin weeks before a woman delivers her infant. The first stage begins with the woman's first contractions and continues until she is dilated fully (10 centimetres, or 4 inches), which means the cervix has stretched to prepare for birth. The second stage is the active stage, in which the pregnant woman begins to push downward. It begins with complete dilation of the cervix and ends with the actual birth. The third stage, or placental stage, begins with the birth and ends with the completed delivery of the placenta and afterbirth.
Just as pregnancy is different for every woman, the signs of labor and the length of time it can take to go through the three stages will vary from woman to woman.
Some signs indicating that labor may be close (although in fact it might still be weeks away) may include:
• "Lightening." This term describes when the fetus "drops," or moves lower in the uterus. Not all fetuses drop before birth. Lightening gets its name from the feeling of lightness or relief that some women experience when the fetus moves away from the rib cage to the pelvic area. This allows some women to breathe easier, more deeply, and get relief from heartburn.
• Increase in vaginal discharge. Called "show," the discharge can be clear, pink, or slightly bloody. This occurs as the cervix begins to dilate and can happen several days before labor or as labor begins.
If you experience any of the following signs of labor at any point in your pregnancy you should contact your health care provider:
• Contractions every 10 minutes or more often
• Change in color of vaginal discharge
• Pelvic pressure
• Low, dull backache
• Vaginal spotting or bleeding
• Abdominal cramps with or without diarrhea
Sometimes a woman's health care provider will recommend inducing labor (using medically supervised methods, such as medication, to bring on labor) if the health of the mother or the fetus is at risk. Unless delivery is medically necessary, a woman should wait until at least 39 weeks before delivering her infant to give her/him the best chance for healthy outcomes. During the last few weeks of pregnancy, the fetus is still developing its lungs, brain, and liver.