Reproduction Abstracts

Several million babies have been born worldwide since IVF and assisted-reproductive technologies (ART) became available. However, reports link IVF techniques with adverse short- and long-term health outcomes.^1,2,3 Using a mouse model, we investigated the effect of IVF on the total cell number in blastocyst stage embryos and the postnatal health of offspring.

Methods: Experimental groups; (NM) C57/BL6 non-superovulated females naturally mated with CBA males. (IVC) Two-cell stage embryos collected from C57/BL6 superovulated females mated with CBA males and transferred to MF1 pseudo pregnant recipients. (IVF) Conducted on isolated C57/BL6 oocytes from superovulated females using CBA sperm following an IVF protocol;⁴ embryos at two-cell stage transferred as above. Blastocyst trophectoderm (TE) and inner cell mass (ICM) cell numbers from NM and IVF embryos were determined by differential staining.⁵ Offspring were analysed for body weight, systolic blood pressure (SBP).

Results and discussion: NM blastocysts (41 embryos from 12 mothers) had significantly more TE and ICM cells (P<0.05) compared with IVF (25 embryos; 12 mothers). Male (26–40; 27 mothers) and female (21–38; 27 mothers) offspring from IVC and IVF embryos were heavier than NM offspring from week 6 and 5 (P<0.05); respectively; no differences between IVC and IVF weights were present. IVF and IVC induced increased SBP in male (weeks 9 and 15) and female (week 15) offspring vs NM (P<0.05). We conclude IVF causes reduction in blastocyst cell numbers but superovulation and embryo transfer are sufficient to alter offspring growth and SBP. Further offspring growth, SBP and glucose tolerance analyses are underway.