When to jump-start fertilization

When to jump-start fertilization
The implementation of intracytoplasmic sperm injection (ICSI) has enabled men with even the most severe forms of male factor infertility to achieve fertilization and pregnancy—something that had not been possible with conventional in vitro fertilization. With its ability to attenuate defects of the zona pellucida and sperm acrosomal dysfunction, ICSI has become very popular, making it a suitable assisted reproductive technology technique for a variety of infertility indications. However, although rare, some couples suffer from total fertilization failure even with the use of ICSI.
Source: fertstert.org