IVF is a treatment method in which the egg and sperm are brought together in a laboratory environment to achieve fertilization. The term originates from Latin and literally means “fertilization in glass.” First successfully developed in 1978, IVF has since become one of the most widely used assisted reproductive technologies worldwide.

In 1993, the introduction of Intracytoplasmic Sperm Injection (ICSI) — a technique in which a single sperm is injected directly into the egg — marked a major breakthrough, particularly for couples experiencing male factor infertility.

What Are the Stages of IVF Treatment?

The main goal of IVF treatment is to obtain mature eggs, achieve fertilization under laboratory conditions, and transfer healthy embryos into the uterus to establish pregnancy.

IVF treatment consists of four main stages:

• Ovarian stimulation
• Egg retrieval
• Fertilization in the laboratory
• Embryo transfer

1. Ovarian Stimulation

Under natural conditions, women typically produce one egg per month. In IVF treatment, multiple eggs are developed to increase the chances of successful fertilization and pregnancy.

To achieve this, ovarian stimulation medications are administered as subcutaneous or intramuscular injections. The most appropriate protocol and medications are determined individually after medical evaluation.

Stimulation typically lasts 10–14 days, during which follicles (fluid-filled sacs containing eggs) develop. Follicle growth is monitored by ultrasound, aiming for a diameter of approximately 17–18 mm. Blood tests are also performed to measure estrogen hormone levels secrtede by the ovaries.

Premature ovulation is an important risk during stimulation so some medications namely GnRH antagonists are used to prevent this happening.

Scientific evidence shows no long-term harmful effects of these medications on women’s health. Temporary side effects such as bloating, mild weight gain, or emotional sensitivity may occur but resolve after treatment.

2. Egg Retrieval

Egg retrieval is performed using a needle attached to a vaginal ultrasound probe. The procedure lasts about 15 minutes and is carried out under light anesthesia, making it painless.

Fluid from the follicles is aspirated, specimens are sent to laboratory to search for the eggs. After approximately 2 hours of observation, patients can return home and resume normal activities.

3. Fertilization in the Laboratory

Collected eggs are immediately transferred into special incubators that mimic the natural environment of the fallopian tubes.

After resting for 2–4 hours, eggs are fertilized using one of two methods:

• Conventional IVF: Sperm are placed near the egg and fertilization occurs naturally.
• ICSI: A single sperm is injected directly into the egg using a microscopic needle.

Sperm samples are obtained from the male partner on the day of egg retrieval. In cases where no sperm are present in semen, sperm can be surgically retrieved from the testes using a procedure called TESE (Testicular Sperm Extraction). Retrieved sperm may also be frozen for future use.

4. Embryo Transfer

After fertilization, embryo development is monitored closely:

• Day 1: Fertilization occurs.
• Day 2: 4-cell embryo stage.
• Day 3: 8-cell embryo stage.
• Day 4: Morula stage
• Day 5: Blastocyst stage — a more advanced embryo with higher implantation potential.

Embryos are typically transferred on Day 3 or Day 5 after egg retrieval. Day 5 (blastocyst) transfer allows better embryo selection, although both approaches are used depending on embryo development.

According to regulations in Türkiye (since March 2010):

• Women under 35 years: single embryo transfer
• Women aged 35 and above: maximum two embryos

This policy aims to reduce multiple pregnancies while maintaining treatment success.

Embryo transfer is a simple procedure similar to a gynecological examination. It takes approximately 3–4 minutes, requires no anesthesia, and is performed under ultrasound guidance to place embryos into the optimal area of the uterus.

Patients can return to normal daily activities after 1–2 hours of rest, and prolonged bed rest is not necessary.

Successful implantation depends mainly on embryo quality and adequate uterine (endometrial) environment.

Follow-Up After Embryo Transfer

The first pregnancy test is performed 10–12 days after embryo transfer. A blood test measuring β-hCG (Beta Human Chorionic Gonadotropin) provides definitive confirmation of pregnancy.

Approximately one week after a positive test, an ultrasound examination is performed to confirm the presence of the gestational sac. Vaginal ultrasound examinations performed during pregnancy are safe and have no harmful effects on the baby.

Close monitoring during this period aims to ensure early diagnosis of possible conditions such as ectopic pregnancy or miscarriage, allowing timely medical management when necessary.

IVF Success Rates

When IVF treatment was first introduced, pregnancy success rates were around 20%, meaning that 2 out of every 10 patients achieved pregnancy. Thanks to major advancements in laboratory technology and clinical experience, success rates today can reach approximately 50% in suitable patient groups.

The most important factor affecting IVF success is female age, mainly due to changes in egg quality over time.

With increasing age:

• Chromosomal function within the egg declines.
• The cytoplasmic environment of the egg loses efficiency.
• Overall reproductive potential gradually decreases.

Embryo Freezing (Cryopreservation)

Embryo freezing has been safely practiced worldwide and allows embryos obtained during IVF treatment to be preserved for future use.

• Vitrification (rapid freezing) — currently the most widely used method, associated with improved survival and pregnancy outcomes.

When frozen embryo transfer is planned, the uterine lining is prepared and frozen embryos are thawed and transferred into the uterus.

Preparation of the uterine lining during frozen embryo transfer cycles is achieved using oral estrogen medications, which have no proven long-term adverse effects on women’s health.

Possible Side Effects of IVF Treatment

IVF treatment is considered safe; however, as with all medical procedures, certain risks may occur.

Ovarian Hyperstimulation Syndrome (OHSS)

In some patients, ovarian stimulation medications may cause excessive ovarian response.

Possible symptoms include:

• Ovarian enlargement
• Abdominal bloating and fluid accumulation
• Nausea and vomiting

Scientific studies have not demonstrated an increased risk of ovarian, breast, or uterine cancer related to fertility medications.

Egg Retrieval–Related Risks

Bleeding may occur in approximately 1 out of 1,000 procedures. Very rarely, laparoscopic surgery may be required to control bleeding.

Ectopic Pregnancy

In rare cases (1–2%), embryos may implant outside the uterus, most commonly in the fallopian tubes. Early diagnosis allows effective medical treatment in many cases.

Risk of Congenital Anomalies

Extensive scientific data show that babies born through IVF do not have a significant increase in congenital anomalies compared with naturally conceived babies.

Patient Care and Monitoring

Throughout the IVF journey, careful monitoring and individualized treatment planning are essential. Our goal is to ensure maximum safety, optimal success rates, and personalized patient care at every stage of treatment.