title: Zona thinning with a noncontact diode laser in ICSI embryos from women of advanced age.
abstract: OBJECTIVE
  The objective of this study was to determine if the zona thinning (ZT) technique improved the rates of implantation and clinical pregnancy for patients aged > or = 38 years submitted to an ICSI program.
  
  
  METHODS
  A total of 100 patients submitted to ICSI and aged > or = 38 years were divided in a prospective and randomized manner into two groups: Group I - patients submitted to ZT (n = 50); a laser diode with 1.48 microm wavelength (Fertilaser) was used for the ZT procedure with 1-2 irradiations of 10 ms applied to four different positions on the zona pellucida (ZP) of each embryo to thin 60-90% of the ZP (each point with a 15-20 microm length of ZT). Group II - patients with no ZT (n = 50). In both groups, embryo transfer was performed on the second or third day.
  
  
  RESULTS
  The age of Group I patients (39.8 +/- 1.3) did not differ (p = 0.67) from that of Group II patients (40 +/- 1.9). The number of oocytes retrieved at metaphase II from Group I (6.4 +/- 4.2) and Group II (6.8 +/- 5) was similar (p = 0.94). Normal fertilization rates and cleavage rates were similar (p = 0.78 and p = 0.63, respectively) for Group I (71.5 +/- 22% and 96.7 +/- 11%) and Group II (73.5 +/- 19.7% and 96 +/- 11%, respectively). The number of embryos transferred was similar (p = 0.53) for the two groups (Group I = 3.1 +/- 1.3; Group II = 2.9 +/- 1.1). The thickness of the ZP of Group I embryos (16.9 +/- 2.4 microm) did not differ (p = 0.97) from that of Group II embryos (16.9 +/- 2.3 microm). The rates of embryo implantation and clinical pregnancy per embryo transfer were similar (p = 0.67, p = 0.61) for Group I (7 and 16%, respectively) and for Group II (8.2 and 22%, respectively).
  
  
  CONCLUSIONS
  These results suggest that ZT in the population aged > or = 38 years may have no impact on ICSI success rates. However, this conclusion is limited to a situation in which length of the laser ZT was < or = 20 microm and the laser was applied to four different positions.
authors.affiliation: Center for Human Reproduction, Sinhá Junqueira Maternity Foundation, Rua D. Alberto Gonçalves, 1500 /CEP 14085-100 Ribeirão Preto, SP, Brazil.
authors.forename: Claudia G
authors.initials: CG
authors.lastname: Petersen
authors.forename: Ana L
authors.initials: AL
authors.lastname: Mauri
authors.forename: Ricardo L R
authors.initials: RL
authors.lastname: Baruffi
authors.forename: Anagloria
authors.initials: A
authors.lastname: Pontes
authors.forename: José G
authors.initials: JG
authors.lastname: Franco Júnior
mesh_terms: D000328:Adult; D000367:Age Factors; D004624:Embryo Transfer; D005260:Female; D006801:Humans; D007834:Lasers; D008423:Maternal Age; D011247:Pregnancy; D011256:Pregnancy Outcome; D018566:Pregnancy, High-Risk; D020554:Sperm Injections, Intracytoplasmic / Q000379:methods; D015044:Zona Pellucida