title: Outcome of cryopreservation and subsequent programmed replacement of frozen-thawed embryos in an in vitro fertilisation programme: preliminary report and proposals for improvement.
abstract: In order to prevent wastage of good quality embryos and limit the number transferred in fresh in vitro fertilisation (IVF) cycles, 577 supernumerary embryos were cryopreserved for a mean duration of 6.23 +/- 4.7 months (range 1-24). Four hundred and twenty-two have been thawed so far of which 81 (19.19%) were totally lysed, 317 (75.12%) survived with at least 50% of their blastomeres intact and 180 (42.65%) cleaved. Two hundred and sixteen frozen-thawed embryos have been transferred in 62 stimulated and 11 natural cycles involving 61 patients. The mean number of embryos transferred per cycle was 2.96 +/- 0.86. Twenty-one pregnancies resulted from the 62 stimulated cycles (33.87%). No pregnancy occurred in the 11 natural cycles. Overall pregnancy rate was therefore 28.77%. Eleven singletons (eight male; three female) and one set of twins (one male one female) have so far been delivered in good condition:- six (54.5%) by caesarean section, five (45.5%) vaginally, including one by Neville Barnes forceps, one ventouse and the rest were spontaneous. Presentation was cephalic in 10 (91%) and breech in one case (9%). All were delivered at term except one premature (9%). Mean birth weight was 3.23 +/- 0.32 kg for singletons and 2.7 kg for the twins. Despite the diversity of racial, cultural and religious differences in our multinational patient population, we found embryo cryopreservation following IVF generally acceptable and our preliminary results are quite encouraging. Strategies for improving the outcome of future cycles are proposed.
authors.affiliation: Thomson Fertility Clinic, Thomson Medical Centre, Singapore.
authors.forename: O A
authors.initials: OA
authors.lastname: Oyesanya
authors.forename: W S
authors.initials: WS
authors.lastname: Cheng
authors.forename: E M
authors.initials: EM
authors.lastname: Quah
authors.forename: W C
authors.initials: WC
authors.lastname: Cheng
mesh_terms: D015925:Cryopreservation; D004622:Embryo, Mammalian; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome