How long does a morula take to implant

Implantation is the very early stage of pregnancy at which the embryo adheres to the wall of the uterus and begins to form the placenta. Implantation is the very early stage of pregnancy during which the embryo embeds into the wall of the uterus. At this stage of prenatal development, the embryo is a blastocyst. It is by this adhesion that the fetus receives oxygen and nutrients from the mother to be able to grow.

In humans, implantation of a blastocyst occurs between 6 to 12 days after ovulation. In preparation for implantation, the blastocyst sheds its outside layer, the zona pellucida, which binds sperm during fertilization.

The zona pellucida degenerates and decomposes, and is replaced by a layer of underlying cells called the trophoblast. The trophoblast will give rise to the placenta after implantation. During implantation, the trophoblast differentiates into two distinct layers: the inner cytotrophoblast, and the outer syncytiotrophoblast. Chorionic villi : During implantation, extensions of the trophoblast, the syncytiotrophoblasts, embed within the endometrium and form chorionic villi.

The syncytiotrophoblast then implants the blastocyst into the endometrium of the uterus by forming finger-like projections into the uterine wall called chorionic villi.

The chorionic villi grow outwards until they come into contact with the maternal blood supply. The chorionic villi will be the border between maternal and fetal blood during the pregnancy, and the location of gas and nutrient exchange between the fetus and the mother.

The creation of chorionic villi is assisted by hydrolytic enzymes that erode the uterine epithelium. Human chorionic gonadotropin is the hormone that is detected by pregnancy tests, as it is found in the maternal bloodstream and urine. Privacy Policy.

Skip to main content. Human Development and Pregnancy. Search for:. First Week of Development. Fertilization Fertilization occurs when a sperm and an egg have fused together to form a zygote, which begins to divide as it moves towards the uterus. Learning Objectives Describe human fertilization. Key Takeaways Key Points Fertilization is commonly known as conception.

Once the fertilized gamete ovum implants itself in the uterine lining, pregnancy begins. The fusion of male and female gametes sperm and ovum, respectively usually occurs following the act of sexual intercourse.

However, artificial insemination and in vitro fertilization have made achieving pregnancy possible without engaging in sexual intercourse. Prior to fertilization, sperm undergo a process of capacitation in response to conditions in the female reproductive tract, which include increases in motility and destabilization of the cell membrane that allows the head of the sperm to penetrate the egg.

Key Terms fertilization : The act of fecundating or impregnating animal or vegetable gametes. Nondisjunction : Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate properly during cell division.

Cleavage of the Zygote The process of cleavage is the step of embryogenesis where the zygote divides to produce a cluster of cells known as the morula. Learning Objectives Describe cleavage of the zygote. The different cells derived from cleavage, up to the blastula stage, are called blastomeres. For species such as humans, there is little yolk in eggs, and the divisions are relatively symmetrical, or holoblastic.

For other species, such as birds and reptiles, the presence of yolk dictates uneven meroblastic divisions that produce cells of uneven size and distribution. The cells of the morula are at first closely aggregated, but quickly become arranged into an outer or peripheral layer, the trophoblast, which does not contribute to the formation of the embryo proper, and an inner cell mass from which the embryo develops.

Key Terms cleavage : In embryology, this is the division of cells in the early embryo. Rosenwaks et al, in published a study looking at donor embryo transfers done in natural cycles. They got good results when transferring cell embryos with day endometrium the day of the LH surge was called day Formigli et al, in reported uterine lavage of embryos from uteri of donors at 5 days post-ovulation.

The embryos were then transferred to recipient women. This suggests a window of implantation of up to 7 days. Pregnancies resulted from transfers on all days. This suggests a window of at least 6 days. Ovulation — mating — fertilization — and subsequent development to the blastocyst stage occurs. The blastocyst then remains in the uterus without implanting or developing further. In some species, the corpus luteum cyst in the ovary is later reactivated — at which time the embryo implants and continues development.

Click here to learn more. Patient Resource Center. Patient Portal. Request a Consult. Answers to questions about implantation of embryos after in vitro fertilization What is involved in embryo implantation?

Successful implantation requires a competent blastocyst embryo interacting with a receptive endometrial uterine lining When does blastocyst implantation actually occur after an IVF cycle — or in a normal menstrual cycle?

Implantation occurs on day after the egg retrieval Which is 1 to 5 days after a blastocyst transfer Which is equivalent to day of a natural menstrual cycle idealized 28 day cycle How long does embryo implantation take? Once the blastocyst has hatched out of its shell, the actual attachment and invasion of embryonic cells begins within one day. What is the latest chance for implantation of an embryo after an IVF transfer?

What is the cause of late implantation of an embryo in humans? How can we improve implantation rates with IVF? Embryo implantation in humans After fertilization the human embryo begins a 4 day long journey down the fallopian tube and into the uterus.

Integrins extend from the lining of the uterus and from the surface of the blastula. Integrins have many functions in nearly all tissue types, and they have a role in cell adhesion, conveying information about the extracellular environment to the nucleus , and modulating the local immune response.

Immediately following implantation , integrins help regulate gene expression in the embryo. Doctors also look for high concentrations of integrins when they look for areas of uteruses receptive to implantation in assisted reproductive therapy ART , and they use the lack of such concentrations to identify women who may be infertile.

Despite the contact between the blastocyst and the endometrium , implantation can fail. There are many potential causes of errors. If implantation does not occur, the endometrium breaks down and sheds, along with the blastocyst , as part of the menstrual cycle. However, if a blastocyst does implant, then the endometrium remains in the uterus , and together with uterine tissue, becomes the maternal portion of the placenta , called the deciduas.

Once the blastocyst adheres to the uterine wall, the trophoblast secretes enzymes that digest the extracellular matrix of endometrial tissue. The trophoblast cells then begin to intrude between the endometrial cells, attaching the blastocyst to the uterine surface. Further secretions of enzymes allow the blastocyst to bury itself deeply among the uterine stromal cells that form the structural components of the uterus.

Subsequently, trophoblast cells continue to divide and form two extraembryonic membranes. These membranes form the fetal portion of the placenta called the chorion. Additional enzymes and signaling factors secreted by these membranes remodel the uterine vasculature to bathe the fetal or embryonic blood vessels in maternal blood. Chorionic villi are the folds of tissue and blood vessels that connect maternal and fetal blood pools.

Maternal blood diffuses into the villi, and it travels through them into the fetus 's vasculature. Similarly, fetal blood diffuses from the villi and into the maternal vasculature.

Normally fetal and maternal blood do not mix, but the relationship between the two circulatory systems enables the transfer of nutrients and oxygen to the fetus or embryo, and carbon dioxide and urea from the fetus to the mother.

While unique to mammals as a reproductive process, implantation is not unique to the uterus and the trophoblast. In the s, researchers found similarities between the invasive abilities of blastocysts and those of cancer cells. The same trophoblast enzymes that digest the endometrium are also used by tumor cells to burrow into tissues throughout body.