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Title: Periconceptional nutritional and environmental determinants of human embryo health
Author: Kermack, Alexandra Jayne
ISNI:       0000 0004 8501 8970
Awarding Body: University of Southampton
Current Institution: University of Southampton
Date of Award: 2018
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Introduction: Whilst undergoing artificial reproductive treatments, physicians and patients try a wide variety of approaches to improve the periconceptional environment of the developing gametes and embryos and hence the chances of success. Recently, a 'Mediterranean' diet, high in vegetable oils and fish, has been reported to increase pregnancy rates by up to 40%. In addition to parental dietary changes, keeping the embryos in a more stable environment (observing them via time lapse technology rather than removing them from their incubator to grade them) may improve their quality. However, up to now, few prospective randomized controlled trials have investigated the impact of periconceptional dietary interventions or the stability of the embryos' culture environment on fertility outcomes. Methods: Two trials have been carried out to examine these hypotheses: 1. The PREPARE trial: A randomised double blinded controlled trial of 111 couples examining the effect of a six week dietary intervention of omega-3 fatty acids and vitamin D on morphokinetic markers of embryo quality. 2. The PROMOTE trial: A prospective and randomised trial comparing embryo development and metabolic activity of embryos cultured in the MINC (standard benchtop) versus the EmbryoScope (time lapse) incubators. Results: There was a statistically significant increases in Docosahexaenoic acid (DHA) and Eicosapentaenoic acid (EPA) in erythrocytes and in vitamin D in blood serum following the dietary intervention (all p < 0.001). The development of embryos generated from the couples in the study group to the four cell stage (CC4) was accelerated compared to the control group (p < 0.001). These embryos also demonstrated a significantly shortened S3 (meaning more synchronous cell division from the five to eight cell stage) (p=0.031). The fatty acid composition of follicular fluid was altered by the dietary intervention and correlations were made with the embryo quality. The short intervention did not have an effect on sperm quality. Culturing embryos in the EmbryoScope significantly increased the number of blastocysts formed on day 5 (159 EmbryoScope versus 133 MINC; P = 0.015) and altered the carbohydrate utilisation and amino acid consumption and production of those embryos. Conclusions: Improving a couple's preconceptional diet and providing a more stable environment for embryo culture improves markers of embryo quality. Further work is needed to examine whether this improvement causes an increase in pregnancy rates and to establish dosing and the longevity of a dietary intervention before clinical recommendations can be made.
Supervisor: Macklon, Nick ; Calder, Philip ; Houghton, Franchesca Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available