Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

OBJECTIVE: To gain insights into the technical feasibility of maternal spindle transfer (MST) applied in the context of repeated IVF failures for treatment of idiopathic infertility. DESIGN: Prospective pilot study (trial registration number: ISRCTN11455145). SUBJECTS: Twenty-five infertile couples with multiple previous unsuccessful IVF cycles (range 3-11), no previous pregnancy and no history of mtDNA disease participated. The study focused on women <40 years, with previous IVF attempts characterized by a pattern of low fertilization rates and/or impaired embryo development. Couples with severe male-factor infertility were not eligible. Oocyte donors with previous successful IVF outcomes were matched with patients according to standard practice. INTERVENTION: MST was performed by transferring metaphase II spindles from the patients' oocytes into previously enucleated donor oocytes, followed by intracytoplasmic sperm injection, in vitro embryo culture, blastocyst biopsy and vitrification. Only euploid blastocysts were considered for embryo transfer. MAIN OUTCOME MEASURES: Outcome measures included oocyte fertilization, blastocyst development, clinical pregnancy and live birth, incidence of mitochondrial carryover and potential mtDNA reversal, as well as general health of the children born. RESULTS: 28 MST cycles produced 6 children (19 embryo transfers, 7 clinical pregnancies). Paediatric follow-up of the children, performed at intervals from birth to 12-24 months of age, revealed their development to be unremarkable. DNA-fingerprinting confirmed that nuclear DNA of MST children was inherited from both parents, without any contribution from the oocyte donor. For five of the children, mtDNA was derived almost exclusively (>99%) from the donor. However, one child, who had similarly low mtDNA carryover (0.8%) at the blastocyst stage, showed an increase in the maternal mtDNA haplotype, accounting for 30-60% of the total at birth. CONCLUSION: This pilot study provides the first insights into the feasibility of applying MST for patients with idiopathic infertility and repeated IVF failures. Reconstructed oocytes produced embryos capable of implanting, developing to term and producing apparently healthy newborns/babies. However, claims concerning the efficacy of MST with respect to infertility treatment would be premature considering the limitations of this study. Importantly, mtDNA reversal was detected in one child born following MST, a finding with possible implications for mitochondrial replacement therapies.

Original publication




Journal article


Fertil Steril

Publication Date



infertility, maternal spindle transfer, mitochondrial replacement therapies, mtDNA reversal