December 2014 (No. 4) Volume 14
Time-lapse videography of human oocytes following intracytoplasmic sperm injection: Events up to the first cleavage division
Yanhe Liu a,b,*, Vincent Chapple a, Peter Roberts b, Jaffar Ali c, Phillip Matson a,b
a Fertility North, Joondalup Health Campus, Joondalup, Western Australia, Australia
b School of Medical Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
c Department of Obstetrics and Gynaecology, University of Malaya, Kuala Lumpur, Malaysia
A total of 341 fertilized and 37 unfertilized oocytes from 63 intracytoplasmic sperm injection (ICSI) treatment cycles were included for retrospective assessment using the EmbryoscopeTM time-lapse video system. The second polar body (pb2) extrusion occurred at 2.9 ± 0.1 h (range 0.70–10.15 h) relative to sperm injection. All oocytes reduced in size following sperm injection ( p < 0.05) with shrinkage ceasing after 2 h in the unfertilized and at pb2 extrusion in the fertilized oocytes. Pb2 extrusion was significantly delayed for women aged >38 years compared to those <35 years (3.4 ± 0.2 vs. 2.8 ± 0.1, p < 0.01) or 35–38 years (3.4 ± 0.2 vs. 2.8 ± 0.1, p < 0.01), but timing was not related to the Day 3 morphological grades (1–4) of subsequent embryos (2.9 ± 0.1, 2.9 ± 0.1, 2.8 ± 0.2 and 3.0 ± 0.1; p > 0.05 respectively). A shorter time of first cleavage division relative to either sperm injection or pb2 extrusion is associated with both top grade (AUC = 0.596 or 0.601, p = 0.006 or 0.004) and usable embryos (AUC = 0.638 or 0.632, p = 0.000 respectively) on Day 3. In summary, (i) pb2 of human oocytes extrudes at various times following sperm injection, (ii) the timing of pb2 extrusion is significantly delayed when female age >38 years, but not related to subsequent embryo development, (iii) all human oocytes reduce in size following sperm injection, (iv) comple-tion of pb2 extrusion in the fertilized oocytes is a pivotal event in terminating shrinkage of the vitellus, and (v) time to first cleavage division either from sperm injection or pb2 extrusion is a significant predictive marker for embryo quality on Day 3.
Reproductive Biology, 2014 14 (4): 249-256.
* Corresponding author at: Fertility North, Joondalup Health Campus, Joondalup, Western Australia, Australia. E-mail addresses: firstname.lastname@example.org, email@example.com (Y. Liu)