IVF Insemination, Fertilization, and Embryo Development

After eggs and sperm have been retrieved, the next crucial steps in the IVF process occur behind the scenes in the embryology laboratory. Our security in handling eggs, sperm, and embryos is unusually meticulous. Our laboratory protocol, SurTransferSM, calls for two of our board-certified embryologists to be present at all critical steps to avoid any potential errors.

The eggs mature for several hours in culture media. This media is made up of essential amino acids and other components necessary for good embryo development. The nutrients and sperm are then added to the eggs and media, usually in the afternoon of the egg retrieval. The addition of sperm to the culture media is called insemination. Fertilization occurs several hours later when the sperm penetrates the egg.

The stages that follow are very important to the future embryo. After the egg and sperm are united, they begin to form an embryo, which undergoes rapid cell division, growing up to 100 cells by day 5 or 6 of development. At this stage, embryos are called blastocysts.

Several procedures can be performed in the lab to support healthy embryo development. Your doctor will make recommendations about specific procedures if deemed necessary.

Assisted Hatching

A safe and simple procedure commonly performed in our lab, assisted hatching helps the embryo to hatch from its shell, which will enable it to implant in the uterus.

Intracytoplasmic Sperm Injection (ICSI)

In ICSI or Intracytoplasmic sperm injection, for cases of significant male factor infertility, the embryologist identifies the strongest and best swimming sperm and injects them into each egg. Though a large number of sperm are injected, only one will fertilize the egg.

Learn more about ICSI.

Preimplantation Genetic Testing (PGT)

Advances in embryology have enabled us to diagnose genetic abnormalities early before embryos are implanted in the uterus. This process, called preimplantation genetic testing or PGT may be recommended for aspiring parents who:

  • Are carriers for specific genetic mutations
  • Have a history of recurrent miscarriage
  • Have a history of IVF implantation failure
  • Are of advanced age

In PGT, a few cells are removed from the blastocyst-stage embryo and sent to a PGT laboratory for evaluation. The cell's genetic material is then tested to identify genetic mutations or chromosomal abnormalities, depending on the specific type of genetic testing that is ordered. This helps fertility doctors identify unaffected embryos that can be selected for embryo transfer. 

Learn more about PGT.

Freezing Eggs, Sperm, or Embryos for Future Use

The PFC IVF laboratory operates a state-of-the-art cryopreservation program that is available to freeze eggs, sperm, and embryos.

Egg Freezing

Instead of having their eggs inseminated and fertilized immediately after retrieval, patients have the option of freezing their eggs for later. In many cases, patients choose egg freezing as a long-term fertility preservation solution, but it can also be useful for short-term needs, such as:

  • Giving the body a rest after the stimulation and egg retrieval stages of IVF
  • Taking control of the timing of the IVF cycle for personal or logistical reasons
  • Allowing the body to return to a normal hormonal balance before embryo transfer

Ultimately, the decision to freeze eggs and take a break between IVF stages or cycles is a personal one and should be made in consultation with your fertility doctor based on your unique circumstances and goals.

Sperm Freezing

Male patients who have had their sperm collected surgically may freeze a sperm sample(s) for a future IVF cycle, and thus eliminate the need for further surgery. Occasionally we will freeze sperm for men who cannot attend on the day of their partners' egg collection procedure, or for men who are anxious about producing a sample.

Embryo Freezing

If an IVF cycle yields several high-quality embryos, they can be frozen for future use. The freezing process allows for additional IVF cycles at a much lower cost, as the patient will not need to start at the beginning; and with minimal medications. Frozen embryo transfers have allowed many of our patients to achieve more than one pregnancy from a single cycle of ovarian stimulation.

Learn more about embryo freezing.