ANATOMY

Detailed explanation-1: -About 6 days after fertilization, the blastocyst attaches to the lining of the uterus, usually near the top. This process, called implantation, is completed by day 9 or 10.

Detailed explanation-2: -Background. Human embryos are usually cultured to blastocyst stage by Day 5 or 6 after insemination. However, some embryos grow slowly and reach blastocyst stage at Day 7. Acceptable live birth rates have been reported after transfer of Day 7 blastocysts resulted from fresh oocyte in vitro fertilization (IVF).

Detailed explanation-3: -Day 1: The blastocyst begins to hatch out of its shell. Day 2: The blastocyst continues to hatch out of its shell and begins to attach itself to the uterus. Day 3: The blastocyst attaches deeper into the uterine lining, beginning implantation. Day 4: Implantation continues.

Detailed explanation-4: -The blastocyst has a diameter of about 0.1–0.2 mm and comprises 200–300 cells following rapid cleavage (cell division). About seven days after fertilization, the blastocyst undergoes implantation, embedding into the endometrium of the uterine wall.

Detailed explanation-5: -During fertilization, the sperm and egg unite in one of the fallopian tubes to form a zygote. Then the zygote travels down the fallopian tube, where it becomes a morula. Once it reaches the uterus, the morula becomes a blastocyst. The blastocyst then burrows into the uterine lining-a process called implantation.