What is Embryo Transfer? How is Embryo Transfer Done?

Embryo transfer is the process of placing embryos obtained in a laboratory environment, that is, outside the female body, into the uterus of the expectant mother during in vitro fertilization treatment. Embryo transfer, which is also defined as the fertilization of egg cells collected from the expectant mother with sperm cells taken from the expectant father in a laboratory environment and then dropping them into the uterus of the expectant mother, can help achieve pregnancy in couples who cannot have a baby naturally.

What is Embryo Transfer?

Embryo transfer is the process of placing the embryos obtained during in vitro fertilization treatment into the uterus by a specialist doctor under ultrasound guidance (1). Infertility, as it is commonly used among the public, is the inability to achieve pregnancy naturally despite unprotected sexual intercourse for 12 months in women under the age of 35, and despite regular unprotected intercourse for six months in women aged 35 and over (2). According to research, today approximately 15% of couples of reproductive age face infertility problems (3). Today, with the help of developments in health technology, various techniques can be used in couples who want to have a baby but cannot achieve pregnancy naturally.

One of the most frequently used assisted reproductive techniques today is in vitro fertilization, also known as in vitro fertilization. In vitro fertilization treatment is the process of fertilizing the egg cells (OPU) collected from the woman with the sperm sample taken from the man in a laboratory environment and then transferring the quality embryos obtained to the woman’s uterus. The final stage of in vitro fertilization treatment is embryo transfer. After embryo transfer, specialists may continue the treatment process, if necessary, by taking support from various medications to increase the chances of the embryo adhering to the uterus (4, 5).

How is Embryo Transfer Done?

In women who are suitable for in vitro fertilization treatment, the treatment can be carried out with two different procedures: long protocol or short protocol. In the procedure known as the long protocol, the duration of in vitro fertilization treatment may last more than one menstrual cycle, while the short protocol is usually completed in 2-3 weeks (2, 6).

Under normal circumstances, in women with regular menstrual cycles, a certain number of egg cells begin to develop in each menstrual period, but while one of them matures enough to crack, the others are expelled before they mature. The purpose of in vitro fertilization treatment is to ensure the maturation of all egg cells in that cycle with the help of various hormone medications and injections. In this way, women can obtain more than one mature egg cell in that menstrual cycle instead of one mature egg cell. In in vitro fertilization treatment, medications and injections, also known as egg stimulating drugs, are usually started on the 2nd or 3rd day of the menstrual period. Then, experts call the patient to the clinic to check the diameter of the follicles (the structure surrounding the egg cell) with the help of ultrasound and the estradiol hormone level in the patient with the help of blood tests. Generally, when one of the follicles reaches 14 mm in diameter, another medication is started to prevent spontaneous cracking. When the follicles reach a certain diameter, injections, also known as cracking needles, are requested. After this injection, the patient is called to the clinic for egg collection. The man must also provide a sperm sample on the day the eggs will be collected from the woman. In some cases, sperm samples previously frozen under special conditions can also be used. Egg collection can be performed with the help of general anesthesia or sedation. The type of anesthesia to be used during the procedure can be decided according to the patient’s condition and wishes.

Eggs and sperm are brought together in special laboratories for fertilization. While in some cases sperm are expected to fertilize the eggs spontaneously, a single quality sperm can be injected into the egg by microinjection method, especially in patients with insufficient sperm count. After egg collection, patients are usually called to the clinic 2-6 days later for embryo transfer. If necessary, the quality embryos obtained can be frozen and stored for later transfer (5, 6).

Unlike egg retrieval, embryo transfer does not require anesthesia. However, in some cases, mild doses of sedatives may be administered to make patients feel comfortable. One or two embryos evaluated by embryologists are placed in a syringe containing a small amount of liquid, and the syringe is placed at the end of the catheter, which resembles a flexible tube. While the patient is in the vaginal examination position, a special speculum is inserted to ensure uterine patency. Then, the catheter with a syringe at the end is advanced towards the uterus (5, 6).

Today, according to the Regulation on Assisted Reproductive Treatment Practices and Assisted Reproductive Treatment Centers, a single embryo can be transferred in the first and second applications up to the age of 35, two embryos can be transferred in the third and subsequent applications, and a maximum of two embryos can be transferred in all applications over the age of 35. In this way, the risk of multiple pregnancy can be minimized after the procedure (7).

Who Can Have Embryo Transfer?

In vitro fertilization treatment is one of the assisted reproductive techniques used by couples who are diagnosed with infertility and want to have a baby. Some cases of infertility are caused only by women and some are caused only by men. In addition, in approximately 20% of couples diagnosed with infertility, infertility is caused by both the woman and the man (8). Additionally, there are cases of unexplained infertility. In couples diagnosed with infertility, assisted reproductive techniques such as insemination (intrauterine insemination, that is, the delivery of sperm obtained by various methods directly to the woman’s uterus) or in vitro fertilization treatment may help achieve pregnancy (9). Embryo transfer can help couples who need in vitro fertilization treatment for any reason to have a baby. Accordingly, the situations in which embryo transfer can be performed are as follows (5):

• Blockage or damage to the fallopian tubes that makes it difficult for the embryo to fertilize or progress to the uterus
• Ovulation disorders,
• Decrease in egg reserve,
• Endometriosis, which is characterized by the growth of the inner tissue of the uterus somewhere other than the uterus,
• Male causes such as azoospermia (no sperm in the semen) or oligospermia (insufficient sperm number and quality),
• One or both couples have a genetic disorder that is likely to affect the baby’s health in the future.

In addition to the above, it is possible to freeze and then transfer eggs or embryos before treatments that may harm reproductive health, such as cancer treatment (5).

What Should Be Considered After Embryo Transfer?

It is considered normal to experience complications such as swelling in the groin, mild cramps, and constipation after embryo transfer. Some points to consider after embryo transfer can be listed as follows (10):

• Using medications prescribed by the doctor: After embryo transfer, experts may prescribe some medications, such as progesterone hormone, to increase the chances of the embryo attaching to the uterus. It is important to use these medications as recommended by the doctor.
• Eating a healthy and balanced diet: Eating a healthy and balanced diet both before in vitro fertilization treatment and after embryo transfer can increase the chance of success of the treatment. In this process, it is important to adopt a diet rich in minerals such as calcium, magnesium, iron and B vitamins, as well as fresh vegetables and fruits. Additionally, adding high-protein foods to your diet plan can help you have a healthy pregnancy.
• Using folic acid: Research shows that using folic acid, a type of B vitamin, may reduce the risk of babies being born with congenital heart diseases.
• Taking a break from sexual intercourse: Sexual intercourse after embryo transfer may trigger uterine contractions, reducing the chances of the embryo implanting. For this reason, it is beneficial to abstain from sexual intercourse for the period recommended by the doctor after the transfer.

A blood pregnancy test can be performed on average within 10-12 days after the transfer. After the necessary examinations for those who cannot have a baby for various reasons, the couple can decide whether to apply in vitro fertilization treatment or not. For this reason, it is recommended to make an appointment with a specialist doctor in the field to get detailed information about in vitro fertilization treatment and to have the necessary checks.