Objective: Within the last few years smoking activities, as well as infertility, have increased in Italy, and so has the consumption of alternative cigarette devices among women of childbearing age. The aim of this observational study was to evaluate the impact of the consumption of cigarettes and alternatives devices, such as electronic cigarettes and heat-not-burn (HnB) products, on infertile women performing in vitro fertilization (IVF), in specific on the quality of oocytes retrieved in women performing intracytoplasmic sperm injection (ICSI) cycles.
Patients and methods: Prospective observational longitudinal study involving 410 women referring to the Reproductive Physiopathology and Andrology Unit, Sandro Pertini Hospital, Rome, from 2019-2022. All the women enrolled filled out an elaborate questionnaire investigating smoking consumption, before the beginning of ovarian stimulation by antagonist protocol, ovarian pick-up, and subsequent ICSI technique. The outcomes of the study were the evaluation of clinical and ICSI features between the groups of smokers and non-smokers: the number of retrieved oocytes, immature oocytes, and fertilization rate were confronted between the two groups and between cigarette smokers vs. e-cigarette and heat-not-burn (HnB) products smokers.
Results: Clinical parameters were comparable between the group of smokers compared to one of the non-smokers, except for anti-Müllerian hormone (AMH), which was statistically lower in smokers (p<0.05). Regarding IVF hormonal stimulations it appears that the total dose of gonadotropin was statistically lower in the non-smoker's group, compared to smokers (1850±860 UI vs. 1,730±780 p<0.05). Regarding ICSI techniques interestingly the number of oocytes retrieved was lower in the smokers' group compared to non-smokers (5.21±0.9 vs. 6.55±3.5, p<0.001), and the number of empty zona pellucida oocytes was statistically higher in the smokers' group (0.51±0.1 vs. 0.2±0.1, p<0.05). On the other hand, the fertilization rate (FR) was statistically higher in non-smokers compared to the smokers' group (72.16±3.05 vs. 68.12±2.21, p=0.03). Out of the 203 smokers, overall, any statistically significant difference, regarding ICSI results, has been found between the group of cigarette smokers, compared to the group of e-cigarettes plus HnB products smokers.
Conclusions: Smoking negatively impacts human fertility, leading to a reduction of ovarian reserve and ovarian quality, which can negatively impact results in women performing ICSI cycles. Despite the limitation of the study, our results underline that consumption of cigarette alternative devices seems to have a similar negative impact on the quantity and quality of oocytes retrieved in ICSI cycles. Clinicians should emphasize the reduction of exposure to harmful substances derived from the combustion of tobacco smoking, as well as alternative devices, in women of childbearing age.