Dystocia is an abnormal or difficult childbirth

Childbirth

Childbirth is the culmination of a human pregnancy or gestation period with the birth of one or more newborn infants from a woman's uterus...

 or labour. Approximately one fifth of human labours have dystocia.
Dystocia may arise due to incoordinate uterine activity, abnormal fetal lie or presentation, absolute or relative cephalopelvic disproportion

Cephalopelvic disproportion

Cephalo-pelvic disproportion exists when the capacity of the pelvis is inadequate to allow the fetus to negotiate the birth canal. This may be due to a small pelvis, a nongynecoid pelvic formation, a large fetus, or a combination of these factors...

, or (rarely) a massive fetal tumor such as a sacrococcygeal teratoma

Sacrococcygeal teratoma

Sacrococcygeal teratoma is a teratoma located at the base of the coccyx . It is thought to be a derivative of the primitive streak.-Natural history:...

. Oxytocin

Oxytocin

Oxytocin is a mammalian hormone that acts primarily as a neuromodulator in the brain.Oxytocin is best known for its roles in sexual reproduction, in particular during and after childbirth...

 is commonly used to treat incoordinate uterine activity, but pregnancies

Pregnancy

Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...

 complicated by dystocia often end with assisted deliveries, including forceps

Forceps in childbirth

Forceps are a surgical instrument that resembles a pair of tongs and can be used in surgery for grabbing, maneuvering, or removing various things within or from the body...

, ventouse

Ventouse

Ventouse is a vacuum device used to assist the delivery of a baby when the second stage of labour has not progressed adequately. It is an alternative to a forceps delivery and caesarean section. It cannot be used when the baby is in the breech position or for premature births. This technique is...

 or, commonly, caesarean section

Caesarean section

A Caesarean section, is a surgical procedure in which one or more incisions are made through a mother's abdomen and uterus to deliver one or more babies, or, rarely, to remove a dead fetus...

. Recognized complications of dystocia include fetal death, respiratory depression, hypoxic ischaemic encephalopathy (HIE), and brachial nerve damage. A prolonged interval between pregnancies, primigravid birth, and multiple birth have also been associated with increased risk for labor dystocia.

Shoulder dystocia

Shoulder dystocia

Shoulder dystocia is a specific case of dystocia whereby after the delivery of the head, the anterior shoulder of the infant cannot pass below the pubic symphysis, or requires significant manipulation to pass below the pubic symphysis. It is diagnosed when the shoulders fail to deliver shortly...

 is a dystocia in which the anterior shoulder of the infant cannot pass below the pubic symphysis

Pubic symphysis

The pubic symphysis or symphysis pubis is the midline cartilaginous joint uniting the superior rami of the left and right pubic bones. It is located anterior to the urinary bladder and superior to the external genitalia; for females it is above the vulva and for males it is above the penis...

 or requires significant manipulation to pass below it. It can also be described as delivery requiring additional manoeuvres after gentle downward traction on the head has failed to deliver the shoulders.

A prolonged second stage of labour is another type of dystocia whereby the fetus has not been delivered within three hours in a nulliparous woman, or two hours in multiparous woman, after her cervix has become fully dilated.

Synonyms for dystocia include difficult labour, abnormal labour, difficult childbirth, abnormal childbirth, and dysfunctional labour.

The term can also be used in the context of various animals. Dystocia pertaining to birds and reptiles is also called egg binding.