Dilation

Dilation is the gradual opening of the cervix to allow your baby to pass through the birth canal and it happens before labor starts.

During the pregnancy, to protect your baby inside the womb, the cervical opening is closed tightly. When your baby is about to be born, your cervix becomes dilated from 0 to 10 centimeters and it is the longest phase at the time of your labor. But once you reach your labor point of 6 cm dilation, your cervix may start dilating to 10 cm in very few hours.

Effacement

Effacement is the process of shortening and thinning the cervical opening for the preparation for childbirth. Labor may take place after 37 weeks, in the later stages of pregnancy, the effacement happens and the head of the baby drops down into the pelvis. Once the labor begins, your cervix gradually thins out like a sheet of paper which can be measured in percentages. When your cervix is fully thinned, it is said you're 100% effaced which means your cervix becomes completely thin and short, and you may deliver your baby very soon.

Symptoms of Effacement

When your cervix effaces some may or may not have symptoms. Others may feel contractions with slight pain irregularly that produces discomfort. This is because pregnancy conditions vary from woman to woman. Some other possible symptoms are:

• losing your mucus plug
• lots of vaginal discharge
• feel like a baby drops into your pelvis 

Loss of mucus plug

During pregnancy, your cervix is protected and sealed by the mucus plug to prevent uterus infection. When your cervix starts its process of dilation and effacement, you may experience a loss of mucus plug.

As effacement occurs, tiny blood vessels near the cervix may rupture causing a small number of blood spots along with the mucus plug.

Pelvic pain

Cervical dilation and effacement may occur after the head of the baby drops lower into the pelvis region. As the head puts more pressure on your pelvic ligaments, you may experience pain. However, the depth of the pain may vary, initially, it would be like a slight pain, and later a sharp pain may increase.

Contractions

The tightening and relaxing of the uterus muscles are known as Contractions. It may vary in severity and frequency. If you have contractions more regular, frequent, and strong, then you are close to delivery. These contractions' pain differs from false labor contractions, the Braxton–Hicks which occur during the second or third trimester of pregnancy not leading to delivery.

Related: What to Do If Your Water Breaks During Pregnancy?