Pilot study on the influence of diet and lifestyle on IVF/ICSI outcomes

INTRODUCTION

Infertility is a condition that affects one in six couples during the course of their reproductive years and its prevalence has experienced a progressive increase. This fact has led to an increase in the use of assisted reproductive techniques (ART). Although the age of the woman is the most important determinant of the success of ART, there are other factors, known as “lifestyle habits” among which diet, physical activity, stress and the consumption of toxic substances such as tobacco, alcohol, caffeine or drugs, which can influence the probability of gestation.

The aim of this thesis is to study the relationship between different lifestyle habits (smoking, alcohol, physical exercise, stress and diet) in couples who perform an IVF/ICSI cycle and the live birth rate.

MATERIALS AND METHODS

This is an epidemiological, observational, prospective, prospective, multicentre, nationwide (Non-EPA) study. The centres participating in the study were Hospital de la Santa Creu i Sant Pau, Clínica Sagrada Familia, Instituto Universitario Dexeus and Instituto Valenciano de Infertilidad de Madrid (IVI) during the period between 2013 and 2015.A total of 396 subjects were included (252 women and 144 men). The primary variable was the live newborn rate and secondary variables were those related to the intermediate results of the ART cycle (number of total and mature oocytes, fertilization rate, clinical pregnancy rate, miscarriage rate) and seminal parameters.

For the evaluation of the diet, the results of the IVF/ICSI cycle were analysed according to the intake of each of the macro and micronutrients. Subsequently, we analysed whether the intake of the different nutrients was adequate or not according to the recommendations established by the EFSA (European Food and Safety Authority) for the general population and their influence on the results of IVF/ICSI.

RESULTS

The number of total and mature oocytes was significantly higher in non-smoking women when compared to active smokers or ex-smokers with no differences between the latter two groups (12.2±6 versus 9.6±7 and 8.9±4 p=0.002, and 9.4±5 versus 7.1±6 and 7.1±4 p=0.004, respectively). In relation to cumulative smoking dose there was a negative correlation between total dose and the number of total and mature oocytes (r=-0.195 and -0.272, p<0.05, respectively). However, smoking in both men and women did not affect the probability of live birth.

A positive correlation was observed between the number of total oocytes recovered and the number of mature oocytes and total physical activity (r=0.247 and r=0.215, p<0.05, respectively). Likewise, in women who had a live newborn, a higher total physical activity was observed (659±546 vs 499±328 minutes of total physical activity/week, p=0.022).

More women cycling and dancing (58.1 vs 28.3%, p=0.002 and 53.8 vs 30.8%, p=0.028, respectively) and more men swimming had a live birth (51.7 vs 29.9%, p=0.041).

A negative correlation was observed between the degree of stress and the number of total oocytes recovered (r=-0.103, p=0.045), the number of embryos transferred (r=-0.121, p=0.021) and in males, with the percentage of spermatozoa with grade 1 motility (r=-0.125, p=0.018).

There was no negative correlation between the degree of stress, alcohol consumption or coffee consumption with live birth rate for both men and women.

The BMI of women who had a live birth was significantly lower (23.1±3 versus 24.7±3 kg/m2, p=0.014). than that of women who did not have a child.

In the analysis of diet according to EFSA criteria, it was observed that none of the patients with inadequate vitamin B12 intake had a child (p=0.029).

CONCLUSIONS

Smoking in women has a negative impact on intermediate ART outcomes, but no negative impact on male fertility or live birth rate has been observed. Physical activity in both women and men has a positive impact on the probability of live birth.

Stress has a negative effect on the number of total oocytes retrieved, the number of embryos obtained and sperm motility; however, stress has not been observed to impact gestation and live birth rates. Neither coffee nor alcohol consumption in both men and women appear to exert a deleterious effect on IVF/ICSI outcomes. Female BMI influences the probability of live birth. In contrast, male BMI does not appear to impact the probability of live birth. Adequate intake of folic acid, vitamin D, carbohydrates, sugars, fats, proteins, vitamins and minerals in both men and women is generally associated with better intermediate outcomes in IVF/ICSI cycles, but does not appear to impact the probability of clinical gestation or live birth, except for vitamin B12 intake in women.