How An Egg Implants for an Early Pregnancy

The egg released from the ovary makes it’s way to the fallopian tube within 15 minutes.

The fallopian tube is the site of fertilization and thus has to be open, have normal secretions, and be able to contract to usher the fertilized egg to the uterus for implantation.

The egg stays in the fallopian tube for about 3 days.

An egg once fertilized in the fallopian tube an enters the cavity of the uterus as an 8 cell embryo called a morula.

The morula is not capable of implantation, the cells grow and divide several times before the implantation occurs when the morula becomes an early embryo called a blastocyst before implanting.

A cloud of tissue called the zona pellucida sheds during these first few days the tiny morula is in the uterus, and allows for implantation to begin.

Implantation can only occur after there is a complicated sequence of events preparing the tissue with growth factors and fats, and the endometrium (uterine lining) is only receptive to the egg for a few days.

Fibronectin and laminin are tissue products that are the glue allow the first sticking of the young embryo to the lining of the uterus and this process is governed by cytokines.

Finally the early placental tissue known as trophoblast begins to secrete enzymes that breakdown some of the surface matrix between cells of the endometrium and the early placenta grows into the wall of the uterus.

The placenta itself is formed around the time of the missed period, or about two weeks after ovulation, at which time the hormone HCG is easily being secreted into the blood stream, and the pregnancy test becomes positive.

For pregnancy planning advice we suggest you come for an appointment.