Learn about the embryo's nesting window

This is an automatically translated article.

This article is professionally consulted by Master, Doctor Nguyen Thi Cam Van - IVF Lab Doctor - Reproductive Support Center - Vinmec Times City International Hospital.

1. What is fertilization?

Fertilization is the fusion of sperm and ovum to form a new cell called a zygote.
This zygote is a newly formed individual and is the earliest stage of a pregnancy. Normally, fertilization in humans will occur in the outer third of the fallopian tube. Then, the implantation of the egg will take place to develop and form a fetus.

2. What is in vitro fertilization?

In vitro fertilization is a treatment for infertility where sperm and eggs are fertilized in a laboratory to form an embryo. After 2 to 5 days of external culture, the embryos are placed in the woman's uterus.

The success rate of IVF in the world today is about 40-45%. However, in Vietnam, this rate is only about 35-40%. The success rate of IVF will also decrease by 2 to 10% for older women (after age 40).
In vitro fertilization will be indicated in some of the following cases:
Blocked and damaged fallopian tubes or no fallopian tubes. Endometrial optimism . Mild sperm abnormalities. In addition, this method is also applied to cases of unexplained infertility or unable to conceive with other infertility treatments.

3. Embryo nesting window period and embryo transfer

For the method of in vitro fertilization, the doctor needs to determine the time to open the implantation window of the embryo to proceed to transfer the embryo into the patient's uterus. Determining this time will play a very important role in the process of embryo transfer and embryo reception of the in vitro fertilization method.

However, the embryo transfer process can only be guaranteed when the patient conducts an examination and finds that the uterine lining is of sufficient thickness and of good quality, facilitating the implantation and development of the following embryos. when placed in the uterus.

4. How does the embryo implantation window take place?

In the endometrium, the harmonization of the action between estrogen and progesterone is essential to create the necessary changes before implantation.
The endometrium must reach a certain level of estrogen and progesterone must arrive at the right time when the endometrium is ready. The implantation window will be opened with progesterone, when it is ready to reach an appropriate level of progesterone, the endometrium will also achieve a state of readiness to accept the embryo for implantation.
The endometrium only accepts embryos if and only if the implantation window is open, where the implantation window opens on day 18 and closes on day 23 of the cycle. This is the only time that the endothelium can accept the implanted embryo.
If the time of opening the implantation window and the time of the embryo exiting the membrane, it will lead to the embryo reaching the endometrium outside the implantation window and the embryo will not be accepted.

5. What should the patient do before carrying out embryo transfer?

Embryo transfer is one of the simple but very important steps in the in vitro fertilization process. When it is certain that the time to open the implantation window and the test indicators are satisfactory, the patient will be carried out embryo transfer. Because this is a simple technique, the patient does not need to undergo anesthesia and the embryo transfer time only lasts about 5 - 10 minutes. However, the patient needs to arrive 45 to 60 minutes earlier to prepare for the embryo transfer.

Before that, the patient needed to hold his urine for about 2 hours before the ultrasound showed the uterus. Embryo transfer is usually guided by transabdominal ultrasound, so if there is a lot of urine in the bladder, the doctor can see the uterus underneath more easily.
As mentioned above, the embryo attaches to the uterine cavity only if it is placed in the uterus at the right period of the implantation window. Therefore, patients need to adhere to the medication prescribed by the doctor. Currently, there are many different embryo transfer regimens, doctors will consider and specify the most suitable regimen for the patient. But most of the time, if the patient has an embryo on day 3 or 5, the doctor will prescribe the drug 3 or 5 days after placing Progesterone to conduct embryo transfer.
The embryo implantation window period is an important one, especially for in vitro fertilization. Determining this time period will help increase the success rate for this method of insemination.
Vinmec IVF Reproductive Center is the address of infertility - infertility treatment chosen by many couples. So far, the Center has performed fertility support for over 1000 infertile couples with a success rate of 45%-50%. This rate is equivalent to developed countries such as the UK, USA, Australia,...
The center gathers a team of leading experts in the field of obstetrics and gynecology nationally and internationally, trained in centers leading in the world such as in the US, Singapore, Japan, Australia and famous fertility centers in the world. Vinmec Fertility Center can perform most of the advanced assisted reproductive techniques in the world such as: classical IVF, ICSI (intracytoplasmic sperm injection), embryo freezing, culture - embryo transfer, support embryo rupture, reduce multiple pregnancies...help realize the dream of parenthood of hundreds of families across Vietnam.
Master. Doctor. Nguyen Thi Cam Van has experience and strength in performing specialized techniques on assisted reproduction in the IVF lab. Before being an IVF lab doctor at the Reproductive Support Center, Vinmec Times City International Hospital, he had obtained foreign training certificates such as: Certificate of Advanced Reproductive Technology at IVF GangNam Cha, Korea, Certificate of Quality Management in IVF lab at Origio lab, Denmark.
To learn about assisted reproductive methods at Vinmec International General Hospital, you can contact Vinmec Health System nationwide, or register for an online examination HERE.