Embryo Implantation

Embryo implantation is a term with which many women who are struggling to become pregnant are all too familiar.

Women who understand their bodies and how they function know that embryo implantation occurs at the stage in which the blastocyst – the growing embryo – hatches and adheres itself to the wall of the uterus. When this happens, a woman is considered to be pregnant, and at that point, her body begins to provide the nutrients and oxygen needed for the embryo to grow and develop into a baby.  Medical professionals, however, do not all agree on a single definition of embryo implantation. Many define it as the fusion of an egg and sperm to form a zygote (the first stage of development for human cells) or defining a blastocyst as implantation if the age from fertilization is between 7-10 days. It is true that when an embryo attaches to the wall of the uterus, it is considered to be implanted. But not all embryos successfully implant, and this is where things get tricky.

For those having difficulty becoming pregnant, natural embryo implantation often does not happen, resulting in disappointment month after month. However, with the help of in vitro fertilization (IVF), eggs can be retrieved from a woman’s ovaries, fertilized in a laboratory, and then the embryos are transferred back to the woman’s uterus. At this point, embryo implantation can occur.

Some medical professionals argue that implantation is necessary for pregnancy, while others believe that pregnancy can occur without implantation. The latter group believes that as long as the embryo is alive and developing, it can be considered to be pregnant, even if it is not implanted in the uterus. This debate has important implications for research and for how we define pregnancy itself.

Reasons for needing IVF

There are a number of reasons why natural fertilization does not take place within a woman’s body. As a matter of fact, some 12 percent of women in the United States report fertility issues, so it is not at all uncommon for this to occur. Some reasons might include:

• Problems with ovulation – The female in question may not be ovulating in a timely fashion if at all, making successful fertilization difficult.
• Uterine fibroids – These benign tumors that grow on the walls of the uterus can prevent embryo implantation.
• Endometriosis – This disorder where tissue from the uterus implants and grows outside the uterus can make it difficult to conceive.
• Fallopian tube issues – When fallopian tubes are damaged or scarred, the sperm may not reach the eggs to fertilize them, and even if so, the embryos may have a difficult time making it to the uterus.
• Low sperm production or sperm motility issues – Inability to conceive doesn’t lie solely with the female. The male partner may suffer from a low sperm count, sperm that doesn’t move the way it should, or other sperm abnormalities.

The embryo implantation process

If these or other problems hinder conception, IVF is often the answer and can be very successful. Many couples or individuals turn to it each year and experience a happy end result.

One of the major steps in the IVF process is embryo transfer, which occurs after the eggs are retrieved from the woman’s body and are fertilized in the lab. A few days before the transfer is scheduled, the doctor will choose the best embryo for the process; these are those that have the best chance of implanting and developing normally.

Once the day of the embryo implantation arrives, patients will be happy to discover that the procedure for transfer is not difficult or something to fear. In fact, it is actually one of the simplest parts of the entire IVF process.

To perform the transfer, the doctor will use a standard speculum to expose the cervix and will then insert a catheter through the cervix and into the uterus. With the help of ultrasound guidance, the embryos will be passed through the catheter and are thus transferred into the womb.

The process is relatively pain-free and there’s rarely a need for sedation. Some cramping or vaginal discharge may occur afterward or women may be slightly uncomfortable from having a full bladder, which is needed so that the ultrasound is accurate.

It takes about 10 days to determine whether the transferred embryo(s) have implanted themselves in the wall of the uterus. A follow-up appointment will be scheduled to make this determination.

If you’re having difficulty conceiving and are considering IVF, contact Advanced Reproductive Medicine to schedule a consultation with one of our infertility experts or call us at 732-339-9300 for more information about how to get started.