‘Three Parent Embryos / Babies’

Infertility is a major challenge affecting couples worldwide, leading many individuals who wish to become parents to seek treatment at IVF units. Despite significant advances in assisted reproductive technologies, one of the most common reasons for unsuccessful IVF treatments remains poor embryo quality. To improve treatment outcomes and achieve higher-quality embryos, various clinical and laboratory-based approaches have been developed. Among these emerging strategies, techniques targeting the egg cytoplasm have gained increasing attention, giving rise to what is commonly referred to as “three parent embryos.” These techniques are considered part of advanced in vitro fertilization (IVF) treatment approaches.

Approaches to Improve Embryo Quality

Clinical Approaches

  • Different types of treatment protocols

  • Supplement therapies

  • Regenerative therapies such as PRP

  • Stem cell and exosome treatments

Laboratory Techniques

  • Better sperm selection methods such as IMSI, microfluidic sperm chips, or the use of artificial intelligence

  • More sophisticated embryo culture media

  • Time-lapse incubators for continuous embryo monitoring

  • Improving fertilization rates through oocyte activation using calcium ionophore or Piezo electric techniques

Unfortunately, despite all these advanced techniques, poor embryo quality still remains the biggest underlying problem in infertility.

Importance of Egg Cytoplasm in Embryo Development

The egg cytoplasm plays a crucial role in embryo development. Fertilization occurs within the oocyte cytoplasm regardless of the technique used (natural conception, IVF, ICSI, IMSI).

The cytoplasm contains:

  • Mitochondria (the energy center of the cell)

  • Proteins

  • Organelles

  • mRNAs

This microenvironment is the key factor for healthy fertilization and embryo development. A young and healthy cytoplasm can even assist cellular repair mechanisms, helping to repair certain DNA damages. Based on this understanding, “changing the cytoplasm” has emerged as a new tool to address embryo quality problems. This concept is closely associated with PGT and genetic diagnosis, which aim to identify genetic risks before embryo transfer.

What Are Three Parent Embryos?

These techniques have been publicly referred to as “three parent embryos”, because the resulting embryos contain:

  • The mother’s nuclear DNA

  • The father’s nuclear DNA

  • Maternal (mitochondrial) DNA from a donor egg

Techniques Used to Create Three Parent Embryos

Cytoplasm Transfer

Cytoplasm transfer has been performed for many years. During fertilization (ICSI), the embryologist injects a portion of the donor’s oocyte cytoplasm into the mother’s egg cytoplasm together with the husband’s sperm.
The goal is to provide a healthier and more energetic cytoplasmic environment for embryo development.

Maternal Spindle Transfer (MST)

The spindle refers to the egg’s DNA at the metaphase II stage.

Maternal spindle transfer is a more complex technique compared to cytoplasm transfer. In this method:

  • The donor egg is enucleated (its genetic material is removed)

  • The spindle from the mother’s egg is extracted

  • The mother’s spindle is transferred into the enucleated donor egg

  • The reconstructed egg is then fertilized with the husband’s sperm

This process results in a hybrid egg containing the mother’s nuclear DNA and the donor’s cytoplasm.

Although creating a healthier and more energetic environment for embryo development appears promising, several concerns remain:

  • Egg age is still the most critical factor determining embryo quality

  • These techniques are more effective in younger women

  • They cannot correct age-related chromosomal abnormalities

  • Long-term follow-up data on children born using these methods is still limited

  • Mitochondrial DNA carryover from the mother may still occur

Advances in assisted reproductive technologies continue to expand the boundaries of IVF treatment, particularly in cases where embryo quality remains a limiting factor. Techniques involving cytoplasmic support represent an innovative approach aimed at optimizing the cellular environment necessary for healthy fertilization and embryo development. Ongoing scientific research and laboratory expertise remain essential to achieving reliable and safe outcomes in this evolving field.

At Cyprus Hope Fertility | Team-Z, advanced IVF laboratory techniques are applied within a highly specialized and evidence-based framework under the leadership of Dr. Zehra Onar. By integrating scientific innovation with personalized care, each treatment process is carefully designed to support optimal embryo development and reproductive success. Cyprus has become an important destination for patients seeking advanced IVF treatment in Cyprus, including innovative laboratory techniques.