Parturition

Parturition can be defined as an act or process of giving birth to a child. Parturition encompasses a complex series of physiological actions that necessitate the fetus to rotate into its birth position, followed by a series of endocrine changes that end with successful delivery.

The stages of parturition and their duration:

There are three main stages of parturition. The first phase of parturition begins with the commencement of labor. This endures until the cervix is completely dilated. This dilation can be divided into two phases: latent phases where the cervix extends from 0 to 4 centimetres (cm) and active stage where the cervix widens between 4-10 cm, allowing the baby's head and body to sort of fit through. At the week of 37, progesterone levels begin to decline while estrogens levels are high at that time. The new augmented ratio of estrogens and progesterone increases the uterine muscle's sensitivity to other hormones, such as the posterior pituitary hormone oxytocin that stimulates uterine contraction. Prostaglandins are other hormones that are released in response to fetal stress that soften the cervix and increase uterine contractions. More prostaglandins are released when the contractions are greater. The cycle kind of continues a positive feedback loop, and the contractions simply keep becoming stronger and stronger as part of the delivering process, also known as actual labor. The fetus is pushed on the cervix by the contractions, which acts as a trigger to further enlarge the cervix. Additionally, the placenta begins to emit more of the hormone relaxin. It relaxes the pelvic ligaments, allowing the pelvic bones to slightly separate in order to support the growing uterus. During labor, relaxin also assists in further cervix dilating.

Stage 2 ends with the birth of the child.

The third stage of labor begins after childbirth and ends with postpartum (placenta and membrane) delivery. If the doctor has an active role (such as gently pulling on the placenta), Step 3 usually lasts about 5 minutes. Stage 3 may take approximately 30 minutes if the placenta is delivered without assistance. [Sonia Tamanna]