Not pregnant!
The part of the uterus that lies above the point where the uterine tubes attach is called the fundus. It is the top portion of the uterus and is where the fertilized egg implants and grows during pregnancy.
Endometriosis
Assuming you meant '...fertilized egg attaches to the lining of the uterus' - the process is called implantation.
No you shouldn't at all because during a pregnancy the egg attaches itself to th inside wall of your uterus and grows there. During your period an egg goes into your uterus from your overies but doesnt attach itself to the wall of your uterus because it wasnt fertalized by a sperm cell. The egg passing through your uterus it what causes you to bleed during your period.
The condition is called a Uterine Prolapse, and can be very minor to actually visible from the out side of the vagina.
The fundus is the uppermost part of the uterus.
The lining of the uterus
Implantation is the medical term meaning attachment of the zygote to the uterine wall. If the zygote does not attach, a period occurs.
The place in the uterus where the sperm and egg meet and attach.
A retroverted uterus means that your uterus is tilted backwards instead of forwards. This condition does not effect the possibility of getting pregnant.
When the egg don't get fertilized it will come out and since it will not attach in the uterus, the lining of the uterus will change and that is when you bleed. When you are pregnant there are no eggs dropped and the uterus is closed for the baby to be safe.
The fertilized egg will attach itself to the inner lining of the uterus, the endometrium, in most cases. In some instances, it may implant itself into the Fallopian tube, which results in an ectopic pregnancy that can be fatal to the mother and fetus.