P–603 Atretic eggs - frequency and factors which increase their production
Authors: Yunakova M , Kostov I , Magunska N , Antonova I 
Published: August 2021

Abstract

Study question
To investigate the factors which are associated with higher number and share of atretic oocites (AO) such as quintative ovarian reserve, gonadotropin doses, age, BMI, smoking, pelvic surgery. Summary answer: There are convincing data that factors as advanced age, overweight, smoking and pelvic surgery are related to higher share of AO, while stimulation doses not.

What is known already
Atretic eggs are cells that have different deviations in morphology - dark or granular cytoplasm, cytoplasmic fragments, dark area of ​​the pellucid, large perivithelial space, abnormalities in shape and are usless. There is no consensus on the reasons for their formation. Studies demonstrate that combined estimation of the quantitative and qualitative reserve of the ovary is difficult, the transformation of primordial follicles into antral takes months in which the cohort of antral follicles and gametes changes. There are speculations of the likely negative impact of lifestyle factors t like smikong, obesity, age. Other blame higher doses of gonadotropins.

Study design, size, duration
This is a 3 year retrospective study on 2721 IVF/ICSI cycles of controlled ovarian hyperstimulation with long or antagonist protocols. The mean number and share of AO of all oocites retrieved were calculated in order to investigate there relation to factors like ovarian reserve, gonadotropin doses, age, BMI, smoking, history of pelvic surgery. Participants/materials, setting, methods: Depending on the factors investigated, the study groups were formed as follows: = ovarian reserve - &lt;5antral folicles (AF)(n = 307), 5–10AF(n = 994), &gt; 10AF(n = 584) = stimulation doses –1500E (n = 365),1500–3000Е(n = 790), 3000–4500(n = 264), &gt; 4500Е(n = 34) = age - ≤ 30(n = 391), 31–34(n = 467), 35–39(n = 679),≥ 40(n = 412) = BMI - &lt;18.5(n = 109), 18.5–24.9(n = 668), 24.9–30(n = 277), &gt;30(n = 111) = smoking - (n = 431), nonsmoking (n = 286) = pelvic surgery - (n = 572), without surgery (n = 630).

Main results and the role of chance
Regarding the ovarian reserve the mean number of AO rises significantly (Н=59.7, р&lt;0.0001) in paralel with the rise of all oocites retrieved, but the shre of AO stays same in each group (Н=0.39, р=0.828). As regard of the influence of doses of gonadotropins on the share of AO, there is no difference related to the increase of doses (Н=1.69; p = 0.640) - it is comparable,15–20%. The findings concerning age are interesting - the total number of eggs retrieved by age expectedly decreases but the share of AO is same between groups (Н=4.8, р=0.185), around 20%. At the same time in the group of women with only AO retrieved, t43,1% are above 40 years. Overweight and smoking are strongly related to the higher share of AO in obese and smoking women - (Н=11.4; р=0.010) and (U = 54 342; p = 0.005) respectively. In addition among women with only AO, 73,9% are smoking (c2 =5.26; р=0.022). Regarding the influence of pelvic surgery on quality of eggs, data shows higher share of AO among operated one is18% (U = 165815; p = 0.012), probably due to inflammatory processes in the pelvis.

Limitations, reasons for caution
It is possible same women to be prsent in different study groups.
Wider implications of the findings: Increse of stimulation gonadotropins increse the number of eggs retrieved and respectively the chances for pregnancy without compromising the quality of eggs. An increase in the share of AO are related to age, overweight, smoking,pelvic surgery in in the pelvis. These findings suggest preventive measures to preserve women’s fertility potential.

Trial registration number
Not aplicable