Comparison of embryo morphokinetics following intracytoplasmic sperm injection in smoker and non-smoker couples: Are the results different?

OBJECTIVE: To assess early embryo development via time-lapse in smokers and non-smokers.

METHODS: The retrospective study was conducted at Novafertil IVF centers in Konya, Turkey and comprised oocytes of both smoker and non-smoker couples subjected to in vitro fertilisation / introcytoplasmic sperm injection from 2012 to 2015. Age, basal follicle-stimulating hormone, number of stimulation days, amount of gonadotropin used, number of metaphase II oocytes, number of embryos transferred and pregnancy, abortus and clinical pregnancy rates were noted. The embryos were observed for 72 hours in the time-lapse monitoring system. SPSS 22 was used for data analysis.

RESULTS: Of the 257 couples, 132(51.4%) were non-smokers and 125(48.6%) were smokers. A total of 1,414 oocytes were collected from non-smokers and 1,280 oocytes from smokers. There was no significant difference in the age of patients and number of stimulation days between the smoker and non-smoker groups (p>0.05). The number of oocytes, fertilised oocytes, transferred embryos and metaphase II oocytes was significantly less in the smoker group (p<0.05). The rate of pregnancy and ongoing pregnancy was also lower in the smoker group (p<0.05). A difference was observed in time of pronuclei appearance, t8, t9+ cleavage times in time-lapse in the smoker and non-smoker groups (p<0.05). A prolongation was observed in time to pronuclear fading and t2 cleavage times in time-lapse in the non-smoker group (p<0.05). Some chromosomal number and structural defects were identified in pre-implantation genetic in some embryos with prolongation in time-lapse cleavage time in the smoker and non-smoker groups.

CONCLUSIONS: The negative impacts of smoking were not observed at each cleavage phase of embryo development in time-lapse.