Nuchal cord---Cord around the neck

Nuchal cord -or- Cord around the neck occurs when the umbelical cord becomes wraped around the fetal neck 360 degrees.

Nuchal cords are very common, the incidence of nuchal cord

 increases with advancing gestation from 12% at 24 to 26 

weeks to 37% at term

Most are not associated with perinatal morbidity and mortality.In some fetuses and newborns CAN may cause problems, especially when the cord is tightly wrapped around the neck

The cluster of cardiorespiratory and neurological signs and symptoms associated with unique physical features that occur secondary to tight cord-round-the-neck has been referred to as 'tCAN syndrome' (tight Cord Around the Neck Syndrome) 
A small number of studies have shown that nuchal cord and or tCAN can affect the outcome of delivery and may have long-term effects on the infant  and but as a causative factor for stillbirth it is debatable .

Nuchal cord twice around the neck

It is the unique physical features of tCAN syndrome that 

distinguishes it from birth asphyxia even though there are many 

similarities between these two conditions. 

Umbilical cord abnormalities are considered as one of the 

causative factor for birth asphyxia. 

The manifestation of tCAN symptomatology seems to happen both 

in the presence of normal and depressed AGPAR scores. 

Umbilical cord compression due to tCAN may cause 

obstruction of blood flow first in thin walled umbilical vein, while

 infant’s blood continues to be pumped out of baby through the

 thicker walled umbilical arteries thus causing hypovolemia and

 hypotension resulting in acidosis . Anemia  and mild

 respiratory distress may occur. Some of these infants may also 

have facial and conjuctival petechiae and rarely petechiae of

 the neck and upper part of the chest and skin abrasion of neck

 where the cord was tightly wrapped and facial suffusion 

 all of which can also be seen in some postmortem findings of 

stillbirth infants who had tCAN.

 If born alive, some of these infants may also be

 somewhat obtunded with a low tone and have transient feeding 

difficulties. These findings raise the possibility of transient

 encephalopathy, which may lead to long-term complications.