Why was i born 7 weeks premature?

I was born premature in 1965 at a time when most preemies did not survive. I was due Dec 20 and came on Nov 6. My mother had 4 healthy pregnancies before me. There was nothing wrong with the placenta or the cord or anything, it just happened. In fact I was 5 lbs at birth and was sent home after only a week. Premature babies are more common in multiple births mainly because of lack of space in the uterus. Sometimes, the dates can be off by even a month, as my mother suspects in my case, so babies will present early. Mothers who do drugs during pregnancy are more apt to have a preemie as are mothers who don't get enough nutrients and in rare cases extreme stress on the mother can cause a premature birth. Your were a breech as you had not yet turned in utero as babies do that in the last month. Really, in your case there is no justifiable reasoning for the premature birth, none that you know of anyways. Either way, you're here and you're healthy and without complications. Be thankful.