IVF

IVF involves a series of steps,

• IVF stimulation

• Egg collection

• Fertilisation

• Embryo development

• Embryo transfer

• Pregnancy test

IVF stimulation

At the start of your IVF cycle, your nurse will guide you through how to give your injections at home. Most people are able to maintain their normal daily routines while undergoing treatment.

The medications used typically include follicle stimulating hormone (FSH), which helps the ovaries develop multiple follicles, each potentially containing an egg. These injections are usually taken for around 8 to 15 days. In addition, you may be prescribed another medication to prevent premature ovulation, depending on your individual protocol.

Throughout this phase, monitoring is important. You will usually have two to three transvaginal ultrasounds to assess follicle growth and check the thickness of the uterine lining. The number of follicles produced varies between individuals but commonly ranges from around 6 to 15. In some cases, fewer follicles develop than expected, or ovulation may occur earlier than planned. If this happens, your doctor may advise cancelling the cycle and adjusting your treatment approach. This occurs in approximately 5–10% of cycles.

Because of the small risk of unintended ovulation, using contraception during stimulation is recommended if you are sexually active.

When the follicles have reached the appropriate size, you will be instructed to take a “trigger” injection. This is given approximately 35 to 38 hours before your scheduled egg collection and helps prepare the eggs for retrieval by allowing them to mature and detach from the follicle wall. Your care team will then confirm the timing of your egg collection procedure.

Egg collection

Your fertility team will let you know what time to arrive for your egg collection. You will usually be asked not to eat or drink beforehand, as the procedure is performed under sedation.

The egg collection itself typically takes between 5 and 30 minutes. Using a transvaginal ultrasound for guidance, a fine needle is passed through the vaginal wall into each follicle. The fluid within the follicles, which may contain eggs, is gently aspirated.

In uncommon situations, alternative approaches may be required, such as laparoscopic (keyhole) surgery or inserting a needle through the abdomen to access the ovaries. Your doctor will discuss this with you if needed.

The collected fluid is immediately handed to an embryologist, who examines it under a microscope to locate and count the eggs. You will then be informed of how many eggs were retrieved. It’s important to note that the number of eggs collected may differ from the number of follicles seen on ultrasound. In fewer than 2% of procedures, no eggs are obtained. If this occurs, your doctor will review possible reasons and discuss next steps with you.

Before you leave, you will receive instructions about recovery, including suitable pain relief and when to seek medical advice. You will need a support person to accompany you home and stay with you while you recover from the sedation.

After collection, the eggs are taken to the laboratory to be fertilised with sperm. Sperm may come from a fresh sample, a previously frozen sample, or be obtained through a minor surgical procedure directly from the testicle if required.

Fertilisation

Fertilisation occurs when a sperm successfully penetrates an egg, allowing it to develop into an embryo.

There are two main methods used in IVF:

·         Standard insemination, where eggs are placed in a dish with sperm and fertilisation occurs naturally

·         ICSI (intracytoplasmic sperm injection), where a single sperm is injected directly into each mature egg

In some cases, the choice to use ICSI is made on the day of egg collection, particularly if the sperm sample is not ideal. If no sperm is available at the time, the collected eggs may be frozen for future use.

It’s important to understand that not every egg retrieved will be mature, and not all mature eggs will fertilise. In approximately 1–3% of cycles, fertilisation does not occur at all, even when ICSI is used. If this happens, your doctor will discuss possible reasons and outline options for future treatment.

Your fertility team will contact you the day after egg collection to update you on how many eggs have fertilised successfully.

Embryo development

After fertilisation, the egg begins to divide and grow, forming an embryo. By around day 5, the embryo may be ready for transfer into the uterus or suitable for freezing for future use.

It’s important to recognise that not all fertilised eggs will continue developing to this stage.

For example,

·         if 10 eggs are collected, about 9 may be mature.

·         Of these, around 6 might fertilise normally, while some may fail to fertilise or develop abnormally.

·         As development continues, only a portion of these embryos may progress, with others stopping growth along the way.

·         In this scenario, perhaps 3 embryos continue to develop appropriately, while the others stop growing.

·         One embryo may be selected for transfer

·         Any additional suitable embryos frozen for later use.

In approximately 5–10% of IVF cycles, none of the embryos reach a stage suitable for transfer. If this occurs, your doctor will discuss possible explanations and explore options for future treatment.

By days 5 to 7, embryos that continue to develop form a blastocyst.

This stage includes two key parts:

·         an outer layer of cells that will form the placenta,

·         and an inner group of cells (the inner cell mass) that will develop into the baby.

Embryos are assessed and graded based on their appearance and development, and the highest-quality embryo is typically chosen first for transfer.

Embryo transfer

A fresh embryo transfer is typically planned around five days after egg collection. In some situations, your doctor may instead recommend a frozen embryo transfer. This may be advised if there is a risk of ovarian hyperstimulation syndrome (OHSS), if genetic testing of embryos is planned, or if a previous fresh transfer has not been successful and frozen embryos are available.

Frozen embryo transfers can be performed in different ways. They may be timed with your natural ovulation cycle or carried out using hormone replacement with oestrogen and progesterone. These cycles are usually monitored with blood tests and ultrasounds. Occasionally, a planned transfer may need to be cancelled if ovulation occurs earlier than expected or if the uterine lining is not suitable.

During IVF treatment, contraception is recommended if you are sexually active.

When embryos are thawed for transfer, a small proportion may not survive the warming process (approximately 1 in 20). If this occurs and additional embryos are available, another embryo can be thawed.

The transfer procedure itself usually takes about 15 minutes. An abdominal ultrasound is used to guide placement. You will be asked to have a comfortably full bladder. A speculum is gently inserted into the vagina, and the embryo is placed into a fine catheter prepared by the embryologist. The doctor then guides the catheter through the cervix into the uterus, where the embryo is transferred.

After the procedure, you can return to your usual activities, including walking, working, swimming, and emptying your bladder.

Hormonal support with progesterone—often referred to as luteal phase support—is commonly prescribed following transfer. This is usually given as a vaginal medication and is continued until the pregnancy test.

Pregnancy test

A blood test to check for pregnancy is typically performed around 10 days after the transfer. It is important to attend this test even if you experience bleeding. Your medical team will then advise whether to continue or stop your medications based on the result.