Gisbert Beamud, Alexandra

Universitat Autònoma de Barcelona. Facultat de Biociències

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Gisbert Beamud, Alexandra1                                                    1Genetics Degree. Biosciences Faculty of Universitat Autònoma de Barcelona (UAB). Tutor: Francesca Vidal Domínguez BODY MASS INDEX AND TOBACCO INFLUENCE ON ASSISTED REPRODUCTIVE TECHNOLOGY SELECTED REFERENCES: DISCUSSION: BODY MASS INDEX RESULTS: • Deviations from the ideal BMI  and tobacco determine a poor prognosis for ART and also lead to miscarriages • Obesity causes sterility due to anovulation and produces poor embryonic quality. Obese patients require higher doses of gonadotropins in ART • Low BMI leads to anovulation. It can be treated with GnRH analogues or gonadotropins. Men with a low BMI have scant spermatozoid production. • Smoking accelerates menopause by 1-4 years. Smoker women take longer to conceive and require higher doses of gonadotropins. The decrease insperm concentration is dose-dependent on tobacco. Ø It is recommended to normalize the BMI and quit tobacco in order to improve health and obtain better results in ART. Ø Performing further studies on these prognostic parameters in ART would be interesting in the future. INTRODUCTION: Adolphe Quetelet invented the formula for the BMI. It’s a ratio of adult’s weight and height recommended to define obesity. It defines people’s nutritional condition. METODOLOGY Study based on scientific literature research using Pubmed tool (NCBI). Key words: BMI, Tobacco, nicotine, fertility, ART, pregnancy, hormones. Assisted reproduction techniques prognosis depends on various factors. The main ones are the woman’s age, her BMI, obstetric history, toxic factors, the ovarian reserve…  The purpose of this work is to conduct specific bibliographical research on the consequences of smoking and body mass index on assisted reproduction techniques, and on individual fertility. HYPOTHESIS: 1. Extreme BMI values –outside the normal range- lead to poor prognoses for ART 2. Smoking has a negative impact on ART. q Obesity is a chronic disease characterized by excess of adipose tissue. It’s the second cause of early and preventable death. It causes anovulatory sterility and decreases sperm production. q Drastic weight loss or being underweight also affects human health. It causes amenorrhea in women and decrease of sperm motility and concentration. Table 1. BMI Classification  DEVIATIONS FROM THE IDEAL BMI The maintenance of reproductive functions is directly dependent on having a suitable body weight. TOBACCO RESULTS: q Women with BMI>25 are at high risk of sterility by anovulation (or have irregular ovulation)  q BMI>30 is related to lower follicular response in ART, large number of miscarriages, and difficulties in becoming pregnant  q To compensate                                       q However, they have low fertilisation rate (above BMI>30, the fertilization rate is 4% lower for each unit increased)       q                                      à Low sperm motility  (dose-dependents)  q Men with low sperm motility have low levels of aromatase. This enzyme plays an important role in regulating the development, maintenance and maturation of sperm.        MALE ENDOCRINE FACTOR What if the effects of tobacco and obesity are added together? If these two situations occur in parallel, fertility is even more compromised and it will be even more difficult to obtain good results with ART. Tobacco exposure during pregnancy increases future children BMI. According to the other reports, they might have fertility problems.  Fig.4. Roth et al., 2008. Fig.5.Koeppen & Stanton: Berne and Levy Physiology, 6th Edition, 2008. Fig.2. q High levels of oestrogens inhibit the secretion of LH and FSH.  q Low weight involve a drop in sperm motility and a low sperm concentration.  (More significant than extreme BMI) Smoking is one of the main causes of the diseases with the highest mortality rates in the developed world. Tobacco causes prematurity, miscarriages, perinatal mortality, and fertility problems.  • Female smokers have a higher infertility rate than non-smokers, take longer to conceive (6-12 months), have  an increased risk of miscarriage and ectopic pregnancies • Tobacco induces intrafollicular oxidative stress • Nicotine damages ovaries , stimulates acetylcholine receptors   à    and  inhibits GnRH and aromatase à  MALE ENDOCRINE FACTOR FEMALE ENDOCRINE FACTOR • Tobacco alters the formation of spermatozoids, decreases their density, motility and  antioxidant activity. However, this values are often within the normal range. • Infertile smokers have high levels of oxidative stress. • Nicotine and other toxic compounds in tobacco cause DNA fragmentation • Due to GnRH inhibition, testosterone production is affected: spermatic functions drop by 22% Fig.1. • They have earlier menopause (1-4years) • Female smokers who undertake ART, require higher doses of gonadotropins for ovarian stimulation • Oocytes are more prone to chromosomal anomalies • Tobacco harmful effects are more prominent in older women • Women who had smoked had double risk of not getting pregnant via ART Fig.3. • Winter E et al., Early pregnancy loss following assisted reproductive technology treatment. Hum Reprod 2002;17:3220–3 • Carreau S et al., Estrogen, a female hormone involved in spermatogenesis. Advances in Medical Sciences 57: 31-36. • Fedorcsák et al., Obesity is a risk factor for early pregnancy loss after IVF or ICSI. Acta Obstet Gynecol Scand 2000;79:43–8. • Mattison DR et al., The effect of smoking on oogenesis, fertilization and implantation. Semin Reprod Endocrinol 1989;7:291–304.  + DOPAMINA - OESTROGENS + OESTROGENS q Aromatase enzyme (in Leydic cells, adipose tissue, brain...) converts androgens to oestrogens. q Obese individuals have more fat cells. Thus, there is more aromatase activity. q Sertoli and Leydig cells cannot be stimulated. q Testosterone levels drop à Spermatozoid production also drops - TESTOSTERONE+ OESTROGENS q Administrate higher doses of LH and FSH q More days of ovarian stimulation  Women with low BMI have few adipocytes à  - LEPTIN q Decreases GnRH, LH and FSH secretionq Small amounts of estradiol,  irregular ovulation or anovulation.q A drop in GnRH difficult the embryo implantation and decrease the chances of pregnancy.  Fertility treatment can be improved with GNRH analogues or gonadotropins. Table 2. Comparison between different BMI in male and female FEMALE ENDOCRINE FACTOR

Body mass index and tobacco influence on assisted reproductive technology

http://ddd.uab.cat/pub/tfg/2014/126734/TFG_alexandragisbertbeamud.pdf

Body mass index and tobacco influence on assisted reproductive technology

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