disputerer for ph.d.-graden i helsevitenskap og vil offentlig forsvare avhandlingen:
“The role of ovarian reserve markers in fertility and fertility treatment”
Prøveforelesning over oppgitt emne holdes kl. 10.15:
Populærvitenskapelig sammendrag av avhandlingen:
Every woman is born with a definite number of eggs at birth - approximately two million in number. These are gradually used until the age of menopause when they are depleted.
The egg reserve hence decreases with increasing age. The body does not make new eggs over a lifetime and each woman’s egg reserve is thus pre-determined.
The egg reserve can be influenced by several factors which include a person’s genetic make-up, their lifestyle and other factors such as diseases and their treatments. The egg reserve is a key component influencing fertility. The number of eggs at any time point may be estimated by measuring a hormone called anti-Mullerian hormone (AMH) or using an ultrasound scan of the ovary to count the number of visible egg sacs. This is called the antral follicle count (AFC).
The overall aim of this thesis which was made up of four work packages was to study the role of AMH and AFC as surrogate markers of the egg reserve on different aspects of fertility and fertility treatment. The specific aims of each work package were:
1) To compare the AMH hormone production per egg in the various subtypes of women who present with a condition called polycystic ovary syndrome (PCOS). Women with PCOS may present with different complaints/symptoms and we wanted to see if AMH production was different depending on the presenting complaint.
2) To assess the effect of cigarette smoking on the egg reserve in women with fertility problems, and to confirm if self-reported smoking behavior by women matched with more unbiased tests such as breath levels of carbon monoxide and urine levels of cotinine which are both products of cigarette smoke.
3) To assess the effect of treatment with a medication called myo-inositol compared to no treatment, dummy treatment or treatment with other similar medication on hormone and ultrasound markers of egg reserve in women with PCOS, pooling information from previously published studies.
4) To assess the association between egg reserve and embryo quality using a specialised technology called time lapse imaging in women undergoing IVF fertility treatment.
The work for the thesis included collecting socio-demographic and clinical information from women attending the fertility clinic of the hospital and also pooling information from previously published studies. The information for each woman was collected at a single time point to obtain a snapshot view of their egg reserve at that time using blood test to measure AMH and AFC using ultrasound scans. We also collected information pertinent to the study question such as information on smoking or quality of embryos during fertility treatment, age, height, weight and other clinical details which could impact on the results and conclusions for the studies and adjusted for their influences while interpreting the findings.
We found significantly higher AMH production in those women with PCOS who presented with irregular periods (suggesting that these women were not releasing their eggs regularly/not ovulating) as compared to those with regular periods. We think that in these women, this may be an exaggeration of the normal role of this hormone in the body resulting in failure to regularly ovulate/release an egg. In another study, we found that exposure to cigarette smoking in women 35 years or less was not associated with a significant change in the egg reserve compared to nonsmokers. The markers of egg reserve were neither significantly associated with the breath carbon monoxide or urine cotinine levels nor the lifetime smoking exposure.
Our review of the effects of myo-inositol in women with PCOS reported that there was not adequate evidence to show that inositols changed egg reserve markers or subsequent outcomes following fertility treatment.
We found no meaningful direct association between egg reserve (number of eggs) and embryo quality in women undergoing IVF treatment. We found a positive association between the egg reserve and the chance of getting pregnant following IVF treatment. However, this effect is most likely to be indirect because of the increased numbers rather than better quality of the eggs.
Professor II Ganesh Acharya, Institutt for klinisk medisin, Det helsevitenskapelige fakultet, UiT Norges arktiske universitet.
Honorary Professor Roy Homburg, Homerton University Hospital NHS, London, GB.
Professor Kenny A. Rodriguez-Wallberg, Karolinska Institutet og Karolinska Universitetssykehus – 1. Opponent.
Professor Ying Cheong, University of Southampton - 2. opponent.
Professor Rolf Jorde, Institutt for klinisk medisin, Det helsevitenskapelige fakultet, UiT Norges arktiske universitet – leder av komité.
Disputasleder: Professor Brita Elvevåg, Institutt for klinisk medisin, Det helsevitenskapelige fakultet, UiT Norges arktiske universitet.
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