What is Parturition?

Parturition is the mechanisms of signalling the onset of labour (or) a procedure of delivering a fully grown or developed fetus after the completion of pregnancy period.

It is a process of fetus birth with the release of cortisol. During parturition process, the cervix dilates and relaxes. Along with cortisol, oxytocin and estrogen hormones are released to begin the milk production and labour.


During parturition, the uterus contracts to push the fetus towards the cervix and continued till the fetus come down the birth canal. In this process, the head should be first to come out. After parturition, the uterus releases the placenta and it passes out immediately after the fetus is born. Lactation begins – where a mother starts preparing milk for a baby and the first milk, which is called colostrum. This milk contains antibodies, which is required for a newborn baby to protect against the diseases.

Signs of Parturition

The signs of Parturition includes:

  • Bloated abdomen.
  • Development of Mammary glands along with milk secretion.
  • Fully swollen vulva and relaxed pelvic ligaments.
  • Mucous discharge.
  • Feeling relentlessness.
  • Labour and Contractions.

Stages of Parturition

There are three stages of Parturition, which includes:

Stage 1: Preparatory Stage- which is for 2 to 12 hours.

This stage is characterized by the expanding of the cervix, permitting the uterus and vagina to open and become a continuous canal. In this stage, the soft birth canal and the bony birth canal are in relaxed phase and the fetus is in aligned stage along with the lubrication of the birth canal and enlargement of the cervix

Stage 2: Birthing Process – which is for 30 to 180 minutes.

This stage is characterized by the increase in contractions with pressing the abdominal. The placenta, along with the head and forelegs, is forced into the birth canal. There are strong uterine contractions along with abdomen. During this stage, the mother should lay down to allow the fetus to enter the birth canal.

Stage 3: Placenta Expulsion – which is for 1 to 12 hours.

In this stage placenta of ruminants is allowed to expel within 12 hours of the baby born and the contractions of uterus decrease simultaneously.

Hormones involved in controlling the Parturition

There are two main hormones involved in controlling the Parturition.

  • Oxytocin – This hormone helps in the contractions of myometrium during parturition.
  • Relaxin –This hormone helps in the widening of the pelvis by relaxing the cartilaginous joint.

Learn more about Parturition, stages of parturition, and other related topics @ BYJU’S Biology

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