hello ladies!

one of my neighbor was pregnant.. she is my childhood friend. we even got married in the same month.. it was her first pregnancy like mine. she is very healthy and I used to see her very active all these months . taking walks, going out with family and friends etc. today evening I got the news that she lost her baby. her 9th month had started and on previous day she held her appointment with her gync and all was good.. absolutely normal. but very next day she felt some pain in the right side of her abdomen. immediately they went to see her doc. but there they found her baby died in her womb. her baby's neck was wrapped around with cord. she had to undergo c sec to  remove her baby out.. it's so heart breaking. feeling very bad for her. I can imagine their pain. ever since I got this news I am feeling restless. I am stressed, worried, tensed and very very scared.

just want to know how do we come to know if the cord gets wrapped around baby's neck? what are the signs and symptoms?? how common is this?