Kindly explain about shoulder dystocia that occurs as a complication of Normal Vaginal delivery

"After the delivery of the head, the shoulders are pulled gently downward. If this method fails to deliver the shoulders and if it requires extra manoeuvres to deliver the shoulders, then it's called shoulder dystocia. Once the head is delivered and if it slightly pulls back, it's called a turtle sign; then we have to suspect shoulder dystocia. It's a pretty rare condition. The risk factors are if the baby is more than 4 kilos. If the mother has diabetes, we can also be suspect. When there is a prolonged first stage of labour and maternal obesity but still shoulder dystocia can occur in any baby. Suppose there is a disproportion between the baby's weight. So, how do we manage regular shoulder dystocia? Drills are conducted in our hospital, and all the labour room staff are trained to manage shoulder dystocia. The first thing to do is to call for help, and we have certain manoeuvres; we give suprapubic pressure, and we also flex the thigh against the abdomen so much that the opens widens and there is room for the shoulder to come out. So the last assort used in case of shoulder dystocia is either clavicle fracture in severe cases or, you know, pushing the head from below and taking it out through a C-section. How do we prevent shoulder dystocia? Prevention is by controlling diabetes. In case you're diagnosed with gestational diabetes and avoid excess maternal weight gain, regular excess exercise, proper diet, and follow the instructions given by your doctor."