IVF protocol
Women primarily underwent a GnRH antagonist protocol of treatment with
vaginal progesterone gel (Crinone) / estradiol valterate luteal support
or human-derived hCG luteal support (pregnyl) as previously described14. At the time of study (2009-2017) there were
minimal changes to laboratory protocols including culture media,
consumables or equipment used. Eggs were fertilised by either standard
IVF or ICSI in fertilization medium (G-IVF-PLUS, Vitrolife, Gothenberg,
Sweden). Embryos were cultured using the sequential culture media system
supplied by Vitrolife at 6% CO2, 5% O2and 89% N2 where cleavage-stage embryos were grown
until day 3 in G1 PLUS and then moved into G2 PLUS which supports
blastocyst development until embryo transfer on day 4 or day 5. The best
morphological graded embryo was transferred back into the patient using
EmbryoGlue transfer medium (Vitrolife). Patients were in the care of
their treating IVF physician until confirmation of a viable pregnancy
following ultrasound at 6-8 weeks’ gestation, where they were then
referred onto primary obstetrics care.