2 year follow-up of children born after the transfer of embryos obtained by in vitro fertilization of human oocytes cryopreserved in low sodium medium

Abstract

OBJECTIVE: To evaluate the growth and development of children born after the transfer of embryos obtained by in vitro fertilization of human oocytes cryopreserved in a choline-based freezing medium. DESIGN: Long term follow-up study in a medical institution. MATERIALS AND METHODS: Follow-up of 4 ICSI-singletons born between January 2000 and January 2004 in Halitus Medical Institute. Obstetric, peri- and post-natal data were collected and children were examined at 6, 12 and 24 months after birth. The four patients included in the study cryopreserved their oocytes (41 oocytes in total) between 1999 and 2003. Our oocyte cryopreservation program started in 1998. At the moment, 48 patients maintain 629 oocytes cryopreserved (13,1 oocytes/ patient); in 5 cases fertility preservation was the indication for oocyte cryopreservation. RESULTS: Four women, aged 30 ± 0.81(mean ± SD) gave birth to 4 singleton infants. Mean duration of female infertility was 5, 5 years (range 3 to 8 years). Patients had their 41 oocytes thawed; survival rate was: 41,4 % (17 oocytes), fertilization rate was 64,7% (11). Number of embryos transferred/ patient: 2, 4, 3 and 2 (2,75 ± 0,96). All transfers were performed on day 2. Mean birthweight of infants was 2870,75 ± 631 g (range: 2050 to 3550 g). There was 1 preterm delivery at 34 weeks of gestation; neonatal intensive care was required in this case. In all, 1 was a vaginal delivery and the other 3 were caesarean sections. Three healthy girls (75%) and one healthy baby boy (25%) were born. No perinatal mortality occurred. No post-partum complications were observed. At 6, 12 and 24 months of age, weights and heights of children were within normal parameters: mean weights: 7525, 10135 and 12562 g; and mean heights 63, 74,6 and 86,5 cm respectively. Neurological outcome of the four children at the age of 12 months showed normal development. CONCLUSIONS: The obstetric, peri- and post-natal outcome of the four babies was good. Further development of children was normal after 2 years of follow up. To our knowledge, this is the first report to present preliminary follow-up data of children born after oocyte cryopreservation in a low sodium medium. Careful evaluation is essential since choline based freezing technique is relatively new. These promising findings enhance the need for long-term follow-up of children born after this procedure.