Definition and History of IVF
In Vitro Fertilization (IVF) is Latin in origin, literally meaning “fertilization in glass.” This term is commonly known as “test-tube baby treatment” among the public. IVF is an assisted reproductive technique where egg and sperm cells are combined outside the body under special laboratory conditions to achieve fertilization.
The resulting embryos, after successful fertilization, are transferred to the expectant mother’s uterus. The birth of the first successful test-tube baby, Louise Brown, in 1978 marked a turning point in infertility treatment, fulfilling the dream of millions of families to have children since then. Thanks to modern techniques used today, both pregnancy rates and treatment safety have been maximized, making IVF one of the most effective infertility treatment methods available.
In Which Cases is IVF Recommended?
IVF is generally considered as the first option when other, less invasive treatment methods (such as intrauterine insemination – IUI) have failed or are not medically suitable. There are many different indications, including blocked or damaged fallopian tubes, severe male infertility (very low sperm count or motility), endometriosis, unexplained infertility, advanced maternal age, and the need for Preimplantation Genetic Testing (PGT) due to being a carrier of genetic diseases. Furthermore, IVF is the directly recommended treatment path for couples with long-term unsuccessful IUI attempts or reproductive system problems that cannot be corrected with surgery. These complex situations demonstrate why IVF is one of the cornerstones of modern reproductive medicine.
What are the Key Factors Affecting IVF Success?
The success rate of IVF treatment is determined by the complex interplay of many variables. The most critical factor is undoubtedly the expectant mother’s age; as egg reserve and quality rapidly decline after the age of 35. However, embryo quality (laboratory conditions and embryologist expertise), the cause of infertility (for example, tubal factor infertility may offer higher success, while advanced male factor infertility may be challenging), and the uterus’s ability to accept the embryo (endometrial thickness and health) are also vital. Lifestyle factors such as smoking, obesity, and excessive stress can also negatively affect the success rate. A comprehensive evaluation of these factors ensures that the couple receives a personalized treatment protocol and develops realistic expectations.
Stage 1: Ovarian Stimulation and Monitoring
Pre-Treatment Preparation and Evaluation
Before starting an IVF cycle, a comprehensive medical and fertility evaluation of the couple is mandatory. For the woman, ovarian reserve is determined by the Anti-Müllerian Hormone (AMH) level and a basal ultrasound (performed on the 2nd or 3rd day of the menstrual cycle). These reserve tests provide vital information about the drug dosage to be used and the treatment protocol. Additionally, the structure of the uterus, the condition of the fallopian tubes, and general health screenings (infection tests, hormone levels) are performed. For the man, a detailed semen analysis (spermiogram) is carried out. This preparation process is the first and most crucial step in ensuring that the treatment is personalized and focused on maximum success.
Hormonal Drug Protocols (Long Protocol, Short Protocol)
Various hormonal protocols are used for ovarian stimulation. The Long Protocol (which usually involves a Gonadotropin-Releasing Hormone agonist) lasts approximately one month and aims to increase the doctor’s control by suppressing the ovaries’ natural cycle. The Short Protocol (which involves a GnRH antagonist) is shorter and is often preferred for women with low ovarian reserve. These protocols stimulate follicle development with injections containing Follicle-Stimulating Hormone (FSH) and sometimes Luteinizing Hormone (LH). The choice of protocol is a personalized decision determined by the physician based on the patient’s age, AMH level, and previous treatment experiences.
Monitoring Follicle Development with Ultrasound and Blood Tests
Throughout the stimulation period (usually 8 to 14 days), the ovarian response is closely monitored. This monitoring includes regular measurement of follicle number and size with transvaginal ultrasonography and the determination of estradiol (E2), progesterone, and LH levels with blood tests. Ultrasound follow-ups are typically done every few days, and the physician aims for the follicles to reach the desired maturity (usually 18-20 mm). Blood hormone levels indicate whether the ovaries’ response to the medication is optimal and allow for dosage adjustments if necessary. This meticulous monitoring is critical for preventing premature ovulation and determining the precise time for egg retrieval to ensure the highest quality eggs.
Final Egg Maturation (Trigger) Injection
When it is decided that the follicles have reached adequate size and hormone levels are appropriate, the final and most critical injection, the “trigger” injection, is administered. This injection typically contains Human Chorionic Gonadotropin (hCG) and initiates the final maturation of the follicles. Timing requires absolute precision; the egg retrieval procedure (oocyte aspiration) must be scheduled exactly 34 to 36 hours after this injection. Adhering to this precise time window is an indispensable step that directly affects the success of the treatment by ensuring the collected eggs are at the optimal maturity for fertilization.
Stage 2: Egg Retrieval (Oocyte Aspiration)
Pre-Procedure Preparation and Anesthesia
Egg retrieval is a short surgical procedure performed 34-36 hours after the trigger injection. The procedure is usually performed under light sedation or short-term general anesthesia, ensuring that the expectant mother does not feel any pain. The patient must fast for several hours before the procedure. Before the procedure, the patient is asked to empty their bladder and is positioned comfortably. The anesthesiologist closely monitors the entire process to ensure the patient’s comfort and safety. These preparations are essential conditions for the procedure to proceed comfortably for the patient and in a sterile and timely manner for the physician.
Egg Retrieval Technique and Duration
The egg retrieval procedure is performed under the guidance of transvaginal ultrasonography. A fine needle (aspiration needle), passed through the vagina, is guided by ultrasound to each follicle in the ovaries. Negative pressure is applied to aspirate the fluid and egg cells (oocytes) inside the follicle. This follicular fluid is immediately delivered to the embryologists in the laboratory. The embryologists search for the eggs under a microscope and evaluate their quality. The procedure usually takes 10 to 20 minutes, and the number of eggs collected varies depending on the patient’s ovarian reserve and stimulation success.
Evaluation of Collected Eggs
After the collected follicular fluid is examined in the laboratory, the maturity level of the found eggs is of critical importance. For the eggs to be capable of fertilization, they must be at the Metaphase II (MII) stage. Immature eggs (at the GV or MI stage) usually do not fertilize or form poor-quality embryos. The embryologist separates the mature eggs and cultures them in special incubators at a temperature close to body temperature until the fertilization stage. The number of eggs collected and the maturity rate constitute the first significant indicator of success in the IVF cycle.
Stage 3: Sperm Sample Collection and Preparation
Sperm Collection Methods (Ejaculation, TESA, TESE)
The sperm sample from the male partner is typically collected via masturbation on the day of egg retrieval. However, in cases of absence of sperm in the ejaculate (azoospermia) or severe problems with sperm motility, surgical sperm retrieval methods are applied. These methods include Testicular Sperm Aspiration (TESA) or Testicular Sperm Extraction (TESE). TESA/TESE involves surgically retrieving sperm directly from the testicular tissue. The obtained sperm is then prepared for fertilization. Surgical methods significantly increase the chance of success, especially when used with the ICSI (microinjection) technique.
Sperm Washing and Quality Control
The collected or surgically retrieved sperm sample undergoes a special preparation process in the laboratory before the fertilization procedure. This process is called “sperm washing.” The washing procedure aims to remove cell debris, dead sperm, and seminal fluid other than the sperm itself. The goal is to isolate the sperm with the highest motility, best morphology, and highest fertilization potential. This selective process is vital for maximizing fertilization success for both conventional IVF and especially ICSI. This step also helps minimize issues with genetic integrity in the sperm.
Stage 4: Fertilization
Conventional IVF (Traditional Method)
Conventional IVF is the most traditional fertilization method. Mature eggs are combined with a high concentration of prepared (washed and selected) motile sperm in a petri dish. The sperm are expected to fertilize the egg spontaneously and naturally. This method is suitable for couples whose sperm count, motility, and morphology are within normal limits and who are presumed to have had natural fertilization previously. In conventional IVF, the fertilization process is the laboratory application that most closely resembles the natural process. However, fertilization rates may be slightly lower compared to ICSI.
Intracytoplasmic Sperm Injection (ICSI)
ICSI is an advanced method that requires micro-manipulation technique and significantly increases fertilization success. In this method, the embryologist selects a single sperm that looks morphologically best and motile under a high-magnification microscope and injects this sperm directly into the cytoplasm of the egg cell using a special micro-pipette. ICSI becomes mandatory, especially in cases of severe male factor infertility, low fertilization rates in previous IVF attempts, or when sperm is retrieved surgically. ICSI is also generally preferred when advanced techniques like PGT are to be used.
Reasons and Advantages of ICSI Preference
ICSI is preferred not only for couples with sperm issues but also in cycles where PGT is planned, when a low number of eggs are obtained, or in cases of unexplained infertility. The greatest advantage of ICSI is the guarantee of fertilization and the direct bypassing of the barrier between sperm and egg. This provides more predictable and generally higher fertilization rates than conventional IVF. Furthermore, especially when surgically retrieved sperm (TESA/TESE) have low motility and morphological quality, ICSI maximizes the fertilization chance of these sperm.
Fertilization Check and Success Rate
Approximately 16 to 18 hours after the eggs and sperm are combined, the embryologist checks whether fertilization has occurred. Successful fertilization is indicated by the presence of two pronuclei within the egg: one representing the genetic material from the mother and the other from the father. Only normally fertilized eggs (zygotes) are moved to the embryo culture stage. The fertilization rate is generally around 60% to 80% of the number of mature eggs collected. Determining the number of normal fertilizations provides the first information about the embryo development potential at this critical stage of the IVF cycle.
Stage 5: Embryo Development and Culture
Zygote Stage (Day 0)
The egg confirmed to be successfully fertilized is called a “zygote.” This single-celled structure is considered Day 0 of IVF. The zygote contains two separate nuclei (pronuclei). These nuclei merge their genetic material approximately 18 hours later to initiate the first cell division. Embryologists examine the zygote closely not only to confirm fertilization but also to check for abnormal fertilization (e.g., zygotes with one or three nuclei). Abnormally fertilized zygotes are not cultured and are not used for transfer.
Cleavage Stage (Day 2 and 3)
Days 2 and 3 after fertilization constitute the cleavage stage, where the embryo undergoes rapid cell divisions. The embryo is expected to be 4-celled on Day 2 and 6 to 8-celled on Day 3. At this stage, embryologists grade the embryo quality by evaluating the cell count, the equality of cell sizes (symmetry), and the amount of cell fragmentation within the embryo. A high-quality Day 3 embryo should have regular cells and a low fragmentation rate. This evaluation plays a significant role in determining the timing of the transfer.
Blastocyst Stage (Day 5 and 6): Why is Blastocyst Transfer Important?
The advanced developmental stage reached by the embryo on Day 5 or 6, consisting of approximately 100-200 cells, is called the “blastocyst.” The blastocyst has two distinct cell groups: the Inner Cell Mass (ICM) that will form the fetus and the outer layer (Trophectoderm) that will form the placenta. Only genetically healthy and strong embryos can reach this stage. Blastocyst transfer provides higher implantation and pregnancy rates because it synchronizes embryo development with the intrauterine environment and mimics natural selection. Therefore, when possible, blastocyst transfer is preferred to maximize success per transfer.
Embryo Quality Assessment (Grading System)
Embryologists grade embryos under a microscope according to specific criteria. For cleavage-stage embryos, cell count, symmetry, and percentage of fragmentation are used; for blastocysts, ICM and Trophectoderm quality (with letters A, B, or C) are used. For example, a blastocyst graded as 5AA or 5AB is considered of the highest quality. This grading system provides an objective way to select the embryo with the highest pregnancy potential for transfer. The quality grade also determines the embryo’s potential for cryopreservation (freezing and storage).
Time-Lapse Imaging System (Embryoscope)
Traditional embryo culture involves briefly observing the embryos only at certain times (e.g., Day 1, 3, and 5) after taking them out of the incubator. Time-lapse imaging systems (like the Embryoscope) allow embryos to be continuously observed and filmed without ever being removed from the incubator. This technology gives embryologists the opportunity to detect critical developmental events such as division timing and abnormal division patterns. As a result, the selection of the best embryo for transfer can be made more accurately based not only on morphological (shape) but also on kinetic (developmental speed) data.
Stage 6: Embryo Transfer
Preparation of the Uterus (Endometrium)
Before embryo transfer, the inner lining of the uterus (endometrium) needs to be prepared to receive the embryo. This preparation is ensured by the use of estrogen and progesterone hormones in a natural or medicated cycle. Estrogen causes the uterine lining to thicken, while progesterone makes the lining receptive. The endometrial thickness reaching a certain level (usually between 7-14 mm) and having adequate blood flow are mandatory conditions for successful implantation. The transfer is timed to coincide with an optimal window after the start of progesterone treatment.
Transfer Day and Procedure Details
Embryo transfer is the most exciting and usually the least invasive stage of the IVF process. The procedure does not require anesthesia and is performed in a gynecological examination position, without pain. Under ultrasound guidance, the physician passes a thin and flexible catheter through the vagina and cervix to place the embryo in the most suitable area of the uterus. The embryologist loads the selected embryo into the catheter and, after transfer, checks the catheter under a microscope to ensure the embryo has completely detached from the catheter. This procedure usually takes only a few minutes and requires high precision.
How Many Embryos Should Be Transferred? Legal Restrictions
The Assisted Reproductive Treatment regulations in the Republic of Türkiye restrict the number of embryos to be transferred to minimize the risk of multiple pregnancies. The general rule is single embryo transfer for women under 35 in the first two IVF attempts. Two embryos may be transferred for women aged 35 and over or if there has been a history of previous failures. The transfer of three or more embryos can only be done in exceptional circumstances with special medical necessity and ministerial permission. These legal restrictions aim to protect the health of both the mother and the baby.
What to Pay Attention to After Transfer
Immediately after the embryo transfer, the patient is recommended to rest briefly (usually about 30 minutes). However, there is no scientific evidence that prolonged bed rest increases the chance of pregnancy. The patient can return to their normal light daily activities but should avoid heavy lifting, strenuous exercise, and hot baths/saunas. Continuing the progesterone supplementation (which may be in the form of suppositories, gel, or injection) prescribed by the physician is critical for luteal phase support. Avoiding stress and paying attention to a healthy diet are also general lifestyle changes advised during this period.
Stage 7: Pregnancy Test and Evaluation of Results
Waiting Period (Luteal Phase Support)
The period of approximately 10 to 14 days between embryo transfer and the pregnancy test is called the “waiting period” or luteal phase. During this time, the transferred embryo is expected to implant in the uterus and start producing the Beta HCG hormone. In this phase, the uterine lining is supported using hormone supplements such as progesterone and sometimes estrogen. This waiting period is one of the most emotionally challenging times for couples, and patience and strict adherence to doctor’s advice are essential during this process.
Beta HCG Test (Blood Analysis)
For definitive detection of pregnancy, the Beta HCG (Human Chorionic Gonadotropin) level in the blood is measured approximately 10-14 days after the transfer. Beta HCG is the hormone produced by placental cells once the embryo has successfully implanted in the uterus. A result above a certain threshold (usually above 5 mIU/mL) indicates a positive pregnancy. However, for definitive confirmation of pregnancy, the test is repeated after 48 hours to check if the value has approximately doubled. A healthy increase is a strong sign that the pregnancy is progressing normally.
What to Do in Case of a Negative Result
If the pregnancy test is negative, this can cause great disappointment for the couple. Emotional support is very important at this point. After a negative result is obtained, all medications used are discontinued under medical supervision, and menstrual bleeding is awaited. The physician and embryologists review the entire treatment cycle (egg quality, sperm quality, embryo development performance, and uterine preparation) in detail to analyze the reasons for the failure. This evaluation helps determine whether changes should be made to the treatment protocol to increase the chance of success in the next attempt. It should be remembered that many couples achieve pregnancy with more than one attempt.
Costs, Risks, and Emotional Dimensions of IVF Treatment
General Cost Components of IVF Treatment
IVF treatment is not a single cost item but consists of multiple components. The cost includes hormonal medications used (which vary according to the protocol length and dosage), surgical procedure fees such as egg retrieval and embryo transfer, laboratory expenses for embryo culture and monitoring, preliminary tests and continuous ultrasound/blood monitoring fees, and physician and embryologist fees. If additional advanced techniques such as PGT or embryo freezing are used, the cost increases further. This complex and expensive process requires couples to plan their finances in detail before the treatment.
Potential Medical Risks (OHSS, Multiple Pregnancy)
Although IVF treatment is generally considered safe, some risks exist. Ovarian Hyperstimulation Syndrome (OHSS) occurs when the ovaries over-respond to hormonal drugs, manifesting symptoms such as abdominal swelling and nausea; rarely, severe cases may require hospital monitoring. Another significant risk is the risk of multiple pregnancies (twins, triplets). Multiple pregnancies significantly increase the risks of premature birth, low birth weight, and other neonatal complications. Therefore, single embryo transfer is the most encouraged approach in current medical practice. Additionally, there is a very rare risk of bleeding or infection during the egg retrieval procedure.
Why is Emotional and Psychological Support Necessary?
IVF is an emotionally and physically demanding process. Hormonal fluctuations, long waiting periods, financial burden, and the lack of guaranteed success create significant stress and anxiety for couples. Therefore, receiving professional psychological and emotional support during the treatment is critical to prevent burnout and protect the couple’s mental health. Psychological counseling can help couples develop coping mechanisms for anxiety, manage relationship tensions, and navigate the emotional ups and downs of the treatment in a healthier way.
Additional Advanced Techniques and Future Perspectives
Preimplantation Genetic Testing (PGT) and its Role
PGT is the procedure of genetically screening the embryo before it is transferred to the uterus, making IVF an even more advanced treatment method. PGT has three main subcategories: PGT-A (chromosomal number abnormalities), PGT-M (single-gene disorders) and PGT-SR (structural chromosome abnormalities). PGT allows for the selection of genetically healthy embryos, thereby increasing pregnancy success and reducing the risk of genetic diseases. Especially for couples with advanced maternal age, a history of recurrent pregnancy loss, or failed implantation, PGT is an important tool for optimizing treatment chances.
Assisted Hatching
In a natural pregnancy, the embryo must separate from its outer membrane (zona pellucida) to implant in the uterine wall. This separation process is called “hatching.” In some cases (especially advanced maternal age, thick zona pellucida, or frozen embryo use), the embryo’s membrane may harden, making implantation difficult. Assisted Hatching is a procedure performed just before embryo transfer, where a small opening is created in this membrane using laser or chemical methods. This technique aims to increase the chance of implantation by facilitating the embryo’s emergence from the membrane.
Embryo Freezing (Cryopreservation)
Cryopreservation is the process of freezing and storing healthy, high-quality embryos remaining after transfer in an IVF cycle for future use. The rapid freezing technique called vitrification, used today, minimizes the risk of damage to the embryos. Embryo freezing offers couples the chance to attempt again after an unsuccessful trial without undergoing a new ovarian stimulation cycle, or to have a second child after a successful pregnancy. Frozen Embryo Transfer (FET) cycles are less costly and require less physical strain compared to fresh transfers.
Future Perspective in IVF Treatment
IVF and reproductive medicine are rapidly evolving fields. Future trends focus on the use of Artificial Intelligence (AI) in embryo selection and techniques like Non-Invasive PGT (niPGT) to perform genetic analysis without intervening with the embryo. AI can assist embryologists in selecting the embryos with the highest implantation potential by analyzing the development kinetics of the embryos. niPGT aims to completely eliminate the biopsy risk by analyzing DNA in the culture medium. These technological advancements promise to both further increase IVF success rates and make the treatment process safer and more comfortable for patients.
The Importance of Clinic Selection in IVF Application
Success in IVF treatment largely depends on the experience and technological infrastructure of the clinic where the treatment is performed. Clinics with high success rates generally have a team of experienced reproductive endocrinologists, expert embryologists, and an advanced embryology laboratory. The clinic’s ability to apply personalized treatment protocols according to individual circumstances, select the correct stimulation protocol, and use the latest technologies in embryo culture (Time-Lapse, niPGT, etc.) directly affects the chance of pregnancy. It is important for couples to pay attention not only to success rates but also to ethical approaches, patient communication, and laboratory quality when selecting a clinic.