Assisted Hatching and IVF: Everything You Need to Know

Assisted hatching is a precise laboratory procedure carried out by experienced embryologists as part of an IVF or frozen embryo transfer (FET) cycle. The process involves several key steps, from embryo selection to transfer, each designed to give the embryo the best possible chance to implant. Here’s what typically happens — and when. [11]

Step 1: Pretreatment

Time: 1–2 weeks before embryo transfer

Location: Home and clinic

Before any lab work begins, your fertility specialist will review your medical history, previous IVF outcomes, and whether assisted hatching may be beneficial in your case. You’ll sign consent forms and start your prescribed hormonal medications to stimulate the ovaries and prepare the uterus for embryo transfer.

Step 2: Egg retrieval and fertilisation

Time: Around 10–14 days after starting stimulation medication

Location: Clinic

Once your follicles are mature, a short egg collection procedure takes place under light sedation. Your retrieved eggs are then fertilised in the lab — either by conventional IVF or intracytoplasmic sperm injection (ICSI), where a single sperm is injected directly into each egg.

After fertilisation, embryos are cultured and closely monitored over the next few days. By Day 3 (cleavage stage) or Day 5 (blastocyst stage), embryologists assess their development (through embryo grading) and decide whether assisted hatching could support implantation later in the process.

Step 3: Embryo selection and preparation

Time: Day 2–5 of embryo development

Location: Laboratory

Embryologists examine each embryo under a microscope to assess its growth and the appearance of the zona pellucida — the protective outer shell. Assisted hatching is only performed on embryos that are developing normally and meet strict laboratory criteria.

The most common timing is on Day 3 or Day 5, depending on your clinic’s protocol and whether fresh or frozen embryos are being used.

Step 4: The hatching procedure

Time: 5–10 minutes per embryo

Location: Laboratory

Using high-precision micromanipulation tools, your embryologist creates a minute opening in the zona pellucida to help the embryo hatch. This can be achieved through:

• Laser-assisted hatching: A focused laser beam creates a controlled hole in the outer layer (the safest and most common method).
  
  
• Mechanical hatching: A fine glass needle gently thins or pierces the zona.
  
  
• Chemical hatching: A mild acidic solution dissolves part of the shell (rarely used today).
  
  

Each method is performed under strict laboratory conditions to avoid harming the embryo.

Step 5: Embryo transfer

Time: Same day as hatching

Location: Clinic

After assisted hatching, selected embryos are transferred into the uterus using a fine catheter. This procedure is identical to a standard IVF transfer and usually takes only a few minutes. You may be advised to rest briefly afterwards, though most people can return home the same day.

Step 6: The two-week wait

Time: 1–2 weeks after transfer

Location: Home

Once transferred, the embryo continues developing and ideally implants into the uterine lining within 6–10 days. You’ll continue any prescribed progesterone support during this time, and your clinic will schedule a pregnancy test around two weeks after transfer.