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Labour is one of the most important moments of pregnancy. Someone once said that the few centimeters of the birth canal is the distance that we travel shorter but more important in our lifetime.

Childbirth has three fundamental periods, dilation, period expulsive and the third stage.

The onset may be spontaneous or induced for maternal and/or fetal reasons. The induction of labor implies the administration of medications, devices or the performance of certain maneuvers so that the uterine cervix matures and the uterine contractions start.

The period of dilation occurs due to the presence of contractions regular and effective, not always painful, and has a slower phase until reaching 4 cm, and another accelerated phase in which the cervix achieves a full dilation (10 cm). In addition to dilating the uterine cervix during this period its shortening occurs and softening, key aspects to allow the delivery of the fetus that occurs during the expulsive period. During this period the fetus, ideally in the cephalic position, perform certain rotations and push-ups of the head that allow him to pass through the birth canal in the way more favorable as possible.

Right after the delivery of the fetus begins the third period of birth, this should not last more than 30 minutes in ideal conditions and at this time the uterus contracts strongly to expel the placenta and the membranes and reduces the bleeding with a permanent contraction in the following hours.

Childbirth continues to be a mystery in some aspects.

For example, we do not know what triggers its start, if they are only maternal factors or the fetus may be involved.

Thanks to the great advance of anesthetic techniques, the pain of some periods of delivery can be controlled very effectively, mainly with regional anesthesia, which allows to maintain the woman without pain but participating and enjoying all the moments of birth, something that is remembered for life.

Dr. Javier Pérez Pedregosa


Gynecologist. Director of Maternal Fetal Medicine Unit. Hospital Sanitas La Moraleja and HM Puerta del Sur, Madrid. Associate Professor of Medicine. Francisco de Vito