Oxytocin is a protein hormone created in the hypothalamus and stored in the posterior (back side) of the pituitary gland at the base of the brain.  Oxytocin stimulates contraction of the uterus during childbirth and contraction of the mammary glands during breastfeeding. 

 

Where does it come from?

Oxytocin is created in the hypothalamus (in the brain) an stored in the pituitary gland (at the base of the brain).

During childbirth, oxytocin is also released from the placenta in high amounts.

When and why is oxytocin secreted?

Childbirth - oxytocin cause contraction of the smooth muscle of the uterus.  This important for creating the contractions associated with vaginal delivery of an infant.  Oxytocin also helps the mother expel the placenta after birth of the child.  

Breastfeeding - oxytocin stimulates the contraction of smooth muscle cells around the mammary ducts.  This helps with the release of milk and is sometimes referred to milk "let down."  Suckling of the nipple by an infant sends nerve signals to the hypothalamus, which in turn sends nerve signals to the pituitary gland telling it to release oxytocin.

What does oxytocin do?

Oxytocin stimulates contraction of smooth muscle cells in the uterus (during childbirth) and smooth muscle cells of the mammary ducts (during breastfeeding).

What problems are caused by abnormal levels of oxytocin?

Premature labor during pregnancy - the early release of oxytocin may contribute to early labor. 

Delayed labor during pregnancy - The lack of release of oxytocin may contribute to delays in the timing of labor.

Difficulty with breastfeeding - The lack of oxytocin at the beginning of breastfeeding may delay milk release (milk "let down")

How is oxytocin given as a medicine?

Because oxytocin is a protein, it will be digested before it is absorbed in the gastrointestinal tract.  Therefore, ocytocin is given as a shot or intravenously (IV). Some brand names of oxytocin include: Syntocinon and Pitocin.

What does oxytocin given as a medicine treat?

Labor induction - Oxytocin can be given to help start labor and delivery of an infant.

Fetal stress testing - Oxytocin can be given in limited amounts to cause contractions of the uterus in order to test the health of the fetus.  If contractions of the uterus cause abnormal drops in the fetus's heartrate, labor may need to be induced early (or a C-section performed).

Stimulation of breast milk release - Oxytocin may be given to help with the "let down" of milk.