Assisted Hatching

Very early in their development, embryos are surrounded by an outer coating, the zona pellucida. This coating holds together the individual cells of an embryo. Upon arrival of the embryo in the uterus, the outer zona coating dissolves. The embryo can then "hatch" out of the coating and grow larger. 

The embryo will not implant in the lining of the uterus until it hatches. One of the most common barriers to becoming pregnant with in vitro fertilization (IVF) is improper implantation of the embryo. A process called assisted hatching (AH) can be used with IVF to help embryos implant and increase the chances of pregnancy success.

Assisted hatching is recommended for infertile couples if:

• the woman is 38 years or older,
• the woman has a high follicle stimulating hormone (FSH) level,
  
• they have failed to achieve a pregnancy in a prior IVF cycle,
  
• the embryo is transferred at day three,
• the embryos are fertilized using intracytoplasmic sperm injection (ICSI), or
• they are using frozen-thawed embryos (FET).

If AH is part of an IVF cycle, the woman will receive a combination of steroid medications and antibiotics for four days starting on the day of egg retrieval. Steroids will suppress the patient's immune system so that her uterus will not react to the treated embryos. Antibiotics will fend off any possible infection within the uterus.

On the third day after egg retrieval, the embryos will be coated with a small amount of fluid. On the day of AH, the outer shell is thinned so that hatching can occur after transfer to the uterus.

AH may increase the possibility of monozygotic twins, or identical twins. In rare instances, the use of steroids can result in elevated blood pressure, salt or water retention, a higher susceptibility to infection, mood swings, insomnia, osteoporosis, nausea, and allergic reactions. The antibiotic used (usually doxycycline) may increase both skin sensitivity to sun light and the risk of vaginal yeast infection.