During the early days of IVF when it was impossible to keep embryos alive for very long outside of the human body, all embryo transfers took place immediately after fertilization. The procedure was typically performed on the second or third day after egg retrieval.
As scientific advancements continued to be made, embryos were developing well over three days after egg retrieval. Now, many IVF procedures are done upon the 5th day after egg retrieval, when embryos have reached the blastocyst stage.
Today, 3-day embryo transfers are still performed, but these have less likelihood of implantation than those in the blastocyst stage.
When a sperm and egg meet, fertilization occurs. At this point, a zygote is formed. Cells continue to divide and around 5 to 6 days after fertilization, the embryo becomes a blastocyst. The blastocyst differs from an embryo because of its advanced cell development and growth. This includes a fluid-filled cavity and two distinct types of cells: T cells, and the ICM. Around 5 or 6 days after fertilization, a healthy blastocyst will hatch from its protective outer shell known as the zona pellucida. It is around 24 hours after this hatching process that embryo implantation is ready to occur.
Having high-quality embryos to transfer to a uterus is the most important part of the IVF process. Blastocysts are graded by an embryologist to determine which have the greatest likelihood of resulting in pregnancy. The amount of fluid in the cavity, along with the appearance of the T cells and ICM are the features that determine the quality of a blastocyst.
For a couple or individual undergoing IVF, it may be required to decide between an embryo transfer and a blastocyst transfer. This is a decision that is informed by the reproductive endocrinologist and embryologist based on the development of the embryos. This decision comes down to the number of days that are optimal for the embryo/blastocyst to reside in the lab before being inserted into the uterus or the overall number of embryos that continue to develop.
With a blastocyst transfer, the timing is the most dominant factor. An embryo has been fertilized for just two to three days. With intercourse, the embryo would still be residing in the fallopian tubes, having not yet reached the uterus. With IVF, introducing the embryo to the uterus several days before it would biologically arrive is thought to be potentially disruptive to the process. Therefore, the blastocyst transfer may be considered a closer imitation of the naturally occurring biological process. Additionally, blastocyst transfer allows for a more selective choice of transfer specimens. While lab-developed embryos may not have enough time to fully demonstrate their overall viability, more advanced blastocysts can. Additionally, because a more informed decision can be made, fewer blastocysts are typically transferred which reduces the chances of multiple pregnancies.
Prolonged exposure of the embryo to the conditions of a lab (versus the uterus)
Requirement of high-level lab equipment and capabilities
Potential of having no embryos to transfer
After the embryo transfer, you receive instructions before leaving the clinic. These instructions include what medication to take, when your pregnancy test is going to be and any lifestyle restrictions such as bed rest, exercise, no alcohol or caffeine. Clinics vary in the extent of restrictions following transfer. As a rule of thumb: take it easy at least until you hear about the pregnancy test.
Once the embryo has been placed inside the uterus the cells keep dividing and the embryo grows bigger in size. At the blastocyst stage, around development day 6-7 the embryo will have hatched out of it's shell and begins to attach to the uterine lining. The outer surface of the embryo cells are sticky and recognize molecules in the uterus, this allows the initial attachment to happen. Over the next few days the embryo burrows down into the uterine lining and the tiny embryonic sac starts to form. Some people see a little bleeding at this stage referred to as "implantation bleeding," so if you do see this don't be alarmed but make sure you tell your doctor as you might need extra progesterone.
The growing embryo cells secrete Human Chorionic Hormone (hCG), this is the hormone that is detected by a home pregnancy test or the blood test done at your doctors office. Sometimes a positive HCG level can be detected 2-3 days before your official blood test is due. But certain fertility medication can cause a false positive and so make sure you wait long enough for that to clear out of your system before taking a pregnancy test.
You usually take a pregnancy test two weeks after your egg retrieval. On that day, you most likely will have a blood test to detect the exact level of hCG (alternatively a urine test may be done). A positive level indicates that the embryos have implanted. A follow-up test two days later checks if the pregnancy is progressing normally; the hCG level should approximately double every 48 hours.
Unfortunately, not all embryos develop normally; some pregnancies end in miscarriage. Your reproductive endocrinologist follows the hCG blood levels early in the pregnancy followed by one or two ultrasounds between 6 and 10 weeks of pregnancy.
Whatever the outcome of your fertility treatment, it’s very important to stay on all prescribed medication and follow your doctor’s instructions. A normal pregnancy will be followed until approximately 10 weeks gestation at the IVF clinic, at which time you will be referred to a regular obstetrician for prenatal care.
After an egg is fertilized in the laboratory, the cells begin to divide. During these initial stages of development, the embryo is contained in a layer of proteins known as the zona pellicuda. In order to successfully implant into the uterine lining, an embryo has to hatch out of the zona pellucida and attach to the walls of the uterus.
Assisted hatching is a newer lab technique that was developed when fertility experts observed that embryos with a thin zona pellucida had a higher rate of implantation during IVF. With assisted hatching, an embryologist uses micromanipulation under a microscope to create a small hole in the zona pellucida. This happens on the fourth day of embryo development when the embryos contain an average of six to eight cells.
The embryos are stabilized by a holding pipette, and on the opposite side a small pipette containing an acidified solution creates a small defect in the zona pellucida. The embryos are then rinsed to remove any excess acid solution and returned to the incubator for a few hours before transfer into the uterus.
Assisted hatching is thought to be helpful for couples with a poor prognosis whose embryos are thought to lack sufficient energy to complete the hatching process.
According to the American Society for Reproductive Medicine, assisted hatching may be indicated for women with
Advanced Maternal Age (older than 38)
Poor Embryo Quality
Two or more failed IVF cycles
Assisted hatching has been found to help with IVF success in poor prognosis patients.
Researchers found that with assisted hatching, there was an increase in implantation in all women studied, particularly in those over age 38 or those who had an elevated FSH level on Day 3 of the menstrual cycle. Couples with multiple failed IVF cycles also benefited from assisted hatching.
Because assisted hatching is a difficult technique, the success is dependent on the embryologist's experience and technique, it is important to talk with your fertility clinic about how successful they are with the procedure.
Laser assisted hatching (LAH) is a procedure where a laser beam is used to make a small hole in the outer layer of the embryo. This helps the embryo to hatch out and prepare to implant in the woman’s uterus. While most patients choose to use LAH on their embryos prior to an embryo transfer, this procedure is optional and some patients decide not to use LAH at all.
Advanced age and low ovarian reserve may lead to fewer embryos and embryos that are not chromosomally normal; this is one of the leading causes of failed IVF cycles.
Poor egg and embryo quality will lead to a lower chance of the embryos implanting, most likely again due to chromosomal abnormalities.
Some medical diagnoses may lead to a lower chance of success.
Uterine issues may prevent implantation.
Immune and blood clotting factors may prevent implantation or cause early miscarriage.
Sperm factors may produce abnormal embryos that do not implant.
Stimulation protocols may not be optimal and may not produce the necessary number of eggs for success.
An embryo transfer procedure may disrupt the uterine lining if it was extremely difficult.
Clinic and laboratory procedures may be poor.
Errors with medication/instructions may cause the uterine environment to be out of synchrony with the embryo.
Preimplantation genetic screening (PGS) determines the chromosomal status of an embryo by screening all 23 chromosome pairs prior to transfer in an IVF cycle.PGS may be appropriate for couples pursuing IVF due to a history of infertility or recurrent pregnancy loss because a major cause of IVF failure is aneuploidy — embryos with an abnormal number of chromosomes. Aneuploidy can occur in any embryo; however, the chances increase with maternal age.
Selectively transferring embryos most likely to have a normal number of chromosomes (euploid) is important in reducing miscarriage rates and improving IVF success rates. Pre implantation genetic screening has the following benefits:
Mitigates several reproductive challenges associated with maternal age
Leads to greater implantation rates and improved IVF outcomes
Enables single embryo transfers with higher chance of success, reducing multiple births and the complications that can result from it.
Preimplantation Genetic Screening (PGS)
Preimplantation Genetic Diagnosis (PGD).
PGS analyzes biopsied cells from the embryo to screen for potential genetic abnormalities when there are no known potentially inherited disorders. PGD, on the other hand, uses the same process to detect a specific disorder that has a high probability of being passed down from parents to their offspring.
PGS is recommended for parents who have no known genetic abnormalities, as well as patients who meet any of the following conditions:
Female partner age 38 or older
Couples interested in a single embryo transfer
Couples interested in gender selection
History of pregnancy loss (recurrent miscarriage)
History of failed IVF/implantation failure
PGD is recommended for couples that have a genetic predisposition and/or have any probability of passing down a known genetic abnormality. Any couple with a family history of aneuploidy (abnormal number of chromosomes) which results in miscarriage, birth defects, or Down Syndrome can be screened.
In addition, families that have a history of single-gene defects—such as cystic fibrosis, sickle cell anemia, and muscular dystrophy—can consider PGD testing.
Through this procedure, the highly skilled laboratory staff at New England Fertility will determine which embryos are unaffected and therefore the most viable for uterine transfer.
Donor programme is recommended as a last resort, where after all available techniques are exhausted and there is no possibility of a successful parenthood owing to nil sperm or egg , no quality sperm or egg developed from the couple. This programme is done as per the guidelines of Indian Council of Medical Research (ICMR) . Proper consent is obtained from the couples as well as the donor and the identity of the donor & recipient is kept confidential.
The child born through this method is considered to be the legal heir of the beneficiary parents and the child inherits all the rights , that of child born with own gametes.
Surrogacy is employed where a woman have no uterus, under grown uterus or weak uterus incapable carrying the fetus for 10 months. In some cases where the mother suffers repeated implantation failure or miscarriages surrogacy is employed. Also if a woman have other severe chronic illness which endangers her life if conceived in such cases surrogacy is recommended.
Legally the surrogate mother have no rights over the child born out of surrogacy. This treatment is carried out as per the guidelines of ICMR
In India surrogate mother cannot be employed for a foreign couple.
Cryo preservation is preserving the gametes ( Ovum or Sperm) or Embryos in a cryo can filled with liquid nitrogen, maintaining a temperature as low as – 196 degree celcius. In this way the gametes or embryos can be kept alive for long periods and can be thawed and reused at the time of requirement.
The excess embryos or gamets in a IVF treatment can be preserved and reused thus saves time & necessity of redoing costly ICSI .
Cryo preservation is useful for the persons who are likely to undergo chemotherapy or radiation treatment and likely to loose the potentiality due to the treatment. So healthier gametes can be preserved before starting those treatments and can utilize them when required.
As the IVF treatment is costly inorder to improve the success rate more number of embryos are implanted inside the uterus. In some cases all the implanted embryos successfully grow and developed as fetus. That is the reason for more than one baby delivered mostly.
However where the Single Embryo Transfer (SET) is done there is only one baby is delivered. This technique is used only the doctors are confident of the embryo quality which will mostly end up in positive result.
The genetic integrity of the sperm is crucial for successful fertilization and normal embryo development. Sperm DNA fragmentation is a term used to denote when the genetic material within the sperm is abnormal, which in turn may lead to male sub fertility and IVF failure. Conventional sperm examinations (i.e., semen analysis) done for sperm concentration, motility analysis and morphology assessment cannot assess the sperm at the molecular level and as result aid the detection of DNA fragmentation.
A number of sperm DNA fragmentation tests are available on the market, but the one used at the Reproductive Health Group, is the Sperm Comet test which is currently the most accurate than other tests such as SCSA and TUNEL.
High sperm DNA fragmentation does not impair fertilisation or embryo cleavage stages
High sperm DNA fragmentation affects subsequent blastocyst development
Higher the DNA fragmentation levels, higher the chances of failed assisted conception treatment and miscarriage
Sperm DNA fragmentation is higher in subfertile men with abnormal sperm parameters
Men with normal sperm parameters are also found to have high sperm DNA fragmentation
Provides a reliable analysis, beyond the routine semen sample assessment, of sperm DNA integrity that may help to identify men who are at risk of failing to initiate a healthy pregnancy
Information helps in the clinical diagnosis, management and treatment of male infertility
Prognostic value in assessing outcome of assisted conception treatment
One of the causes of infertility is the inability of the uterus to hold on to a healthy embryo. Experts until recently believed that the viability of an embryo is the sole determinant of a successful IVF cycle. But recent studies have discovered that while the quality of embryos is an important factor, the receptivity of the uterus also plays a significant role in deciding the fate of the IVF cycle.
The test called Endometrial Receptivity Array (ERA) not only measures the receptivity of the uterus, but also helps determine the exact time for embryo transfer which offers the best chances of success.
The ERA test is unique because it examines endometrial receptivity as a product of gene expression of the endometrial lining at specific times during a woman’s ovulation cycle. It monitors the cyclical pattern of 238 different genes and determines a personalized window of implantation for each patient. Endometrial biopsy before embryo transfer can accurately predict the day on which implantation may occur in a subsequent cycle. ERA operates on a similar premise and provides an insight into how receptive a woman’s uterus would be at a particular stage in her menstrual cycle. This enables doctors to determine the best time of embryo transfer for a successful implant.
The natural conception is possible through reversal surgery called tubal recanalization. However it depends on the tube condition whether the circumference of the face of tube is smooth or extensively damaged.