New trends in assisted reproductive technology

• Foreword

32 years have passed since the birth of the first IVF baby in the world in 1978. With the advances in medical technology, IVF treatment has become a “deep-in-the-mind” hope of conception for infertile couples. The progress in reproductive technology provides multiple choices for infertile couples to make their dream come true: intrauterine insemination, in vitro fertilization, sperm donation, testicular sperm retrieval, egg donation, surrogate mother (Assisted reproduction act in Taiwan failed), traditional intracytoplasmic sperm injection, ultra-high magnification sperm injection (IMSI), traditional imaging technique, digital chromosomal imaging technique, slow embryo freezing technology, ultra-fast embryo freezing technique (vitrification), etc.
 

• What is intrauterine insemination?

Intrauterine insemination (IUI) is performed through taking ovulation stimulation pills as well as injections, and vaginal ultrasound-guided monitor of follicle maturation, when the follicle is almost mature, ovulation inductionis triggered by a hormone injection. The sperms was retrieved from the husband, after wash, sperms of good quality was delivered into the uterus for fertilization.
 

• Methods and procedures of intrauterine insemination

Normal women have only one egg per cycle, and the number and quality of eggs obtained by ovulation induction are better than those produced by normal cycles. In order to have more and better eggs, some drugs, such as ovulation stimulation drugs or injections, are used during the process of intrauterine insemination.

The sperms for intrauterine insemination are obtained after screening and purification. A wash step is required to remove all impurities. Usually, an ejaculatory abstinence interval of 3 to 4 days is required before obtaining the semen via masturbation, using of condom is prohibited, both hands and sexual organ must be cleaned before ejaculating directly into the sterile container, the semen has to be delivered to the laboratory within two hours for screening and purification of sperms with good quality and motility.

Usually the eggs for intrauterine insemination are obtained by stimulation, vaginal ultrasound-guided monitor of follicle maturation, and then when the follicle is mature, ovulation induction is triggered and arranging the time for embryo transfer. Embryos are transferred to the patient’s uterus through a high-tech and disposable catheter, which has the advantages of reducing infection and increasing the pregnancy rate.After retrieval of the best sperms, the catheter is implanted into the uterus through the cervix. The advantages are no anesthesia and hospitalization is required, and after laying down for half hour to increase pregnancy rate, the patients are allowed to discharge.
 

• What is in vitro fertilization?

In vitro fertilization is carried out as follow. Sperms obtained by masturbation and eggs retrieved from vaginal ultrasound guidance are cultured in the laboratory. Fertilization is performed in vitro and after the fertilized eggs are transferred into the uterus of the wife after successfully develop into embryos in the culture system (Figure 1).

Methods and procedures of in vitro fertilization：

1. Normal women have only one egg per cycle, and the number and quality of eggs obtained by ovulation induction are better than those produced by normal cycles. In order to have more and better eggs, some drugs, such as ovulation stimulation drugs or injections, are used during the process of in vitro fertilization.
    
2. In general, eggs required for IVF are obtained by stimulating ovulation. It takes about 4 to 5 days to monitor the maturation of follicles with vaginal ultrasound. Egg retrieval will be arranged once the follicles are mature. The retrieval surgery is carried out through vaginal ultrasound guidance and directly from the ovaries. The advantages are no wound formation, rapid recovery, and no hospitalization.
    
3. The sperms for intrauterine insemination are obtained after screening and purification. A wash step is required to remove all impurities. Usually, an ejaculatory abstinence interval of 3 to 4 days is required before obtaining the semen via masturbation, using of condom is prohibited, both hands and sexual organ must be cleaned before ejaculating directly into the sterile container, the semen has to be delivered to the laboratory within two hours for screening and purification of sperms with good quality and motility.
    
4. Laser assisted hatching (LAH) of embryos uses a laser beam to remove a small part of zone pellucida (Figure 2) to facilitate the hatching of embryos as well as the implantation in the uterus. The pregnancy rate can be enhanced by 10% to 20% by LAH.
    
5. The aim of intracytoplasmic sperm injectionis to treat severe microinjection surgery is used to treat severe sperm problems or failure in the union of egg and sperm. Through microsurgery, the sperm is directly injected in to the egg to force fertilization, the fertilization rate is about 85%, similar to normal fertilization. If there are sufficient numbers of eggs, a 40% to 50% pregnancy rate can be achieved.Ultra-high magnification sperm injection (intracytoplasmic morphologically selected sperm injection, IMSI) involves the magnification of sperm to at least 6300x (Figure) to improve the observation of live sperm, followed by microinjection of the selected sperm in to oocyte. With IMSI, both fertilization rate and embryo quality can be improved!
    
6. Another new equipment, chromosome (spindle) digital imager (Figure 4) can detect spindle abnormality, and can observe the location of chromosome such that chromosome damage can be prevented during sperm microinjection, as well as prevent embryo damage which will lead to abnormal fertilization or embryonic development, which in turn results in pregnancy failure. Spindle observation is not possible in traditional microinjection, which could result in chromosome damage, abnormal fertilization and developmental abnormalities.
    
7. Embryo freezing is carried out as part of the IVF procedure, if there are excess embryos, part oh tem can be cryopreserved, and if the current embryo transfer successfully leads to pregnancy, these frozen embryos can be stored until the couples willing to have another child; and if the current transfer does not lead to pregnancy, the cryopreserved embryos can be thawed in the next cycle for transfer. No ovulation stimulation is required again. Thanks to ultra-fast embryo and oocyte freezing technique (Figure 5), there are successful cryopreservation or successful implantation of more than 1500 embryos each year. The average pregnancy rate of frozen embryos is as high as 50 to 60%.
    
8. Preimplantation genetic diagnosis (PGGD) technology (Figure 6) is a technology to screen embryos with genetic defects and implant normal embryos. At day 3 of culture, the embryos are developed into 8-cell stage, and 1 to 2 blastomeres were extracted for PGD via embryo biopsy. Its main advantage is that it avoids selective abortion, as PGD makes it highly likely that the baby will be free of genetic diseases such as thalassemia, hemophilia, Down's disease, and muscular dystrophy.