EMBRYOLOGY
Our embryology laboratory is a full service, New York Sate accredited laboratory with state-of –the –art equipment. We offer conventional IVF, Intracytoplasmic Sperm Injection (ICSI), Assisted Hatching (AH), Preimplantation Genetic Diagnosis (PGD), Embryo Cryopreservation (freezing) and Embryo Thawing. Our embryology team consists of 4 highly trained embryologists who are skilled in all aspects of IVF and embryo manipulations.

Conventional InVitro Fertilization (IVF)
Our laboratory offers conventional IVF to our patients, whereby the eggs are retrieved and are then exposed to sperm and incubated for 18 hours. They are then observed under a microscope, and the presence or absence of fertilization is determined.  The embryos (eggs which have fertilized) remain in culture media in the incubator until transfer or cryopreservation.

Intracytoplasmic Sperm Injection (ICSI)
ICSI is the process of injecting a single sperm directly into one oocyte (egg) using micro tools on a micromanipulator. Eggs are about the size of a grain of sand and a sperm is much smaller than the egg.

ICSI was first developed in the early 1990's as a solution for patients that had severe male factor. Since that time, thousands of healthy babies have been born thanks to ICSI. A patient having a very low sperm count may still be able to father a child. Since only one sperm per egg is needed, patients with the rarest of sperm counts can be given the chance at creating a pregnancy through this procedure.

Patients with no sperm in their ejaculate are referred to a urologist or a consultation.  The urologist may perform a procedure known as PESA (percuatenous epididymal sperm aspiration) where sperm is aspirated from the epididymus in an in-office procedure, and then used for ICSI. If there is no sperm in their epididymus, they may opt for a testicular biopsy. The patient usually receives anesthesia for this procedure. A biopsy tool is utilized to retrieve samples of the testicular tissue which is examined for sperm in the laboratory. Sperm that is discovered can then be used for ICSI.

The process of ICSI begins following egg retrieval. For a step by step tour of oocytes and embryos click here. The eggs are cultured in media in an incubator for several hours. Cumulus cells surrounding the eggs are then removed. Once these cells are removed each egg can be graded for quality, and the maturity of each egg determined. Only mature eggs can be fertilized and therefore only mature eggs are injected with sperm. Each egg is injected with one sperm, and placed into dishes containing culture media. The eggs are cultured in an incubator at a constant temperature of 37ºC, 100% humidity and 6% CO2 concentration for 18 hours. They are observed under a microscope, and the presence or absence of fertilization is determined. Fertilized embryos remain in culture media in the incubator until they are transferred into the patient’s uterus and/or cryopreserved.

Assisted Hatching (AH)
Assisted Hatching is performed to assist embryos in hatching from their  shell (zona pellucida). The zona pellucida initially helps to protect the egg and resulting embryo, but it is essential that the embryo hatch from the zona pellucida for it to implant on the uterine wall and create a pregnancy. Assisted Hatching may help patients with increased FSH levels, who are of advanced maternal age, or whose embryos have thick zonas. Patients who have embryos cryopreserved and are preparing for a Frozen Embryo Transfer (FET) can also benefit from AH. The freezing process may harden the zona pellucida. Creating a small slit in the zona pellucida facilitates in its eventual hatching. There are three types of AH:

Laser Assisted Hatching (LAH) – This is the method that we currently use at CNY Fertility Center in which a laser is used to create an exact opening in the zona pellucida. This technology is the newest method of assisted hatching. The precision that the laser offers helps to minimize embryo damage during this micromanipulation.

         Assisted Hatching (AH) via Laser Assisted Hatching (LAH)

Partial Zona Dissection (PZD) - A thin needle is used to physically create a slit in the zona pellucida. This process itself does not injure the embryo as the tool penetrates the shell only, and does not penetrate the individual cells comprising the embryo.

Assisted Hatching (AH) via Partial Zona Dissection (PZD)

Acidic Tyrode's (AT) - Acid Tyrode's is a solution which is applied to the zona pellucida using a tiny pipette which slowly breaks down the exposed area of zona pellucida, thus creating an opening.

Embryo Transfer
Embryos are transferred to the patient’s uterus on days 3, 4 or 5. The day of transfer and number of embryos transferred will depend on several factors. Patient age, infertility factor(s), embryo quality, previous failed cycles and other factors are taken into account. Embryos are selected in the laboratory and loaded into a catheter. A speculum is placed in the vagina and the soft-tipped catheter is gently placed into the uterus. Ultrasound is used to guide the catheter to the proper location, the embryos are released into the uterus, and the catheter is removed. Patients often feel that embryo transfer is the easiest part of the IVF process. 

Embryo Cryopreservation (Freezing)
Surplus embryos remaining after the transfer are evaluated by Dr. Kiltz and the embryologist to determine if their quality meets the criteria for cryopreservation.  NOT ALL PATIENTS WILL HAVE EMBRYOS FOR FREEZING. Embryos which are cryopreserved may be used in a subsequent frozen embryo transfer (FET) cycle. Not all embryos will survive the cryopreservation or thawing process.

Embryo freezing is a process where embryos are immersed in a series of solutions which dehydrate the cells and replace the water molecules with cryoprotectant, which protects the integrity of the embryo during the freezing process. The embryos are then loaded into special straws, labeled with the unique identifiers of the patient. The straws are placed in a freezer specifically manufactured to freeze embryos. These straws are then placed in tanks of liquid nitrogen for long term storage. There is no known time limit for how long embryos can be stored for.

Do you have remaining cryopreserved embryos, and want to know what your options are? Click here to learn more.

Preimplantation Genetic Diagnosis (PGD)

What is PGD?
Preimplantation Genetic Diagnosis (PGD) is a technology used to screen embryos created from IVF with ICSI for genetic diseases, before they are transferred back to the female's uterus. PGD is used to screen embryos for single gene defects such as Tay-Sachs, Huntington Disease, Sickle Cell Anemia and Cystic Fibrosis. It can also test embryos for chromosomal disorders such as Down's Syndrome and for X-linked diseases like Hemophilia. Additionally, PGD may be used for women who suffer recurrent pregnancy loss from chromosomal abnormalities and advanced maternal age. Screening and transferring only unaffected embryos reduces the rate of miscarriage and may help to alleviate the decision to terminate a pregnancy due to a genetic defect.

What happens during the PGD process?
In this process embryos are created by using ICSI for insemination. The embryos that fertilize and begin to divide are cultured to Day 3 where they are 8-10 blastomeres (cells) in size. At this point a hole is made in the zona pellucida of the embryo, very similar to embryo hatching, but it is used for a different purpose. Once the hole has been made in the zona pellucida a biopsy micro tool is used to gently remove one or two blastomeres from the embryo. This does not harm the embryo because at this point the cells have not begun to differentiate. Differentiation means that certain cells will develop into certain tissues of the fetus. The 8-10 blastomeres are composed of identical genetic material, and will continue to divide and grow properly even if one or two cells are biopsied. The incident of embryo damage during this process is very low, but does exist as in any other micromanipulation. Once the blastomeres are biopsied, they are processed according to the testing to be performed, and sent to a laboratory specializing in PGD analyses for definitive results.

How are the results determined?
Results from the PGD are obtained, and the laboratory is able to determine which embryos are not affected by the genetic disease being screened for. At that point, generally on Day 5, the healthy embryos are transferred back to the patient in anticipation of creating a viable pregnancy. An HCG beta is drawn 2 weeks from the date of egg retrieval to determine if a pregnancy has been initiated.

What else do I need to know?
As with any diagnostic procedure, PGD is not 100% accurate. Some embryos have mosaicism which means that not all the blastomeres are comprised of identical genetic material. In this event embryos which have been determined healthy may in fact be affected by the genetic disease. Patients may undergo an amniocentesis or chorionic villus sampling (CVS) to confirm that the fetus is negative for the genetic disease.

Images of PGD

(Updated 2/7/06)