Impact of Preimplantation Genetic Screening On the Rate of Ultrasound-Detected First Trimester Fetal Anomalies
Julia Brachtchenko1, Larissa Kan-ool 1, Ran Antes1, Valeriy Kuznyetsov 1, Agata Galewicz-Sojecki1, Nikki Legro1, Sergey Moskovtsev 1, 2, Svetlana Madjunkova 1and Clifford Librach1,2,3,4,5
1CReATe Fertility Centre, 2Department of Obstetrics and Gynecology, 3Department of Physiology 4Institute of Medical Sciences, University of Toronto; 5Department of Gynecology, Women’s College Hospital; Toronto, Canada.
Introduction: Preimplanation genetic screening (PGS) is an important assessment tool to select euploid embryos for transfer, in order to increase the chances of a viable and healthy pregnancy. However, PGS alone does not fully eliminate the risk of an abnormal pregnancy, particularly those not related to whole chromosomal rearrangements. First trimester ultrasound and nuchal translucency (NT) scan are first tier tests for morphological screening of the developing fetus. The aim of this study was to determine the rate and type of abnormalities detected by first trimester (T1) ultrasound among patients undergoing different fertility treatments and to evaluate the impact of PGS testing on pregnancy outcomes.
Hypothesis: It was hypothesized that PGS should leads to the selection of embryos with good developmental potential and should decrease miscarriage rates as well as the rate and type of abnormalities when compared to IVF only and non-IVF achieved pregnancies.
Materials and Methods: We conducted a retrospective chart review of patients treated for infertility at CReATe Fertility Centre from January-December, 2015. Three groups of patients (n=189, with positive βHCG test) and their T1 pregnancy outcomes were compared based on their fertility treatment (Figure 3): Group 1: In-Vitro Fertilization (IVF) with PGS for euploid embryo selection, Group 2: IVF without PGS and Group 3: Intrauterine insemination (IUI) or timed-intercourse (TI) cyclemonitoring. Patient’s clinical information, cycle information and pregnancy outcomes were collected for all pregnancies (Figure 3). Chi-square statistics and significance of p<0.05 with confidence intervals of 95% were used for statistical analysis.
Conclusion: Preimplanation genetic screening is an excellent diagnostic tool when used in combination with NT scans. This combination reduces the rates of miscarriages and increases the chances for normal pregnancy at first trimester ultrasound-scan by two fold. IVF/PGS and first trimester US should be utilized together to increase the chances of a successful and healthy pregnancy.
Significance: PGS-tested embryos selected for transfer lead to a significantly lower rate of miscarriages and had a lower rate of abnormal nuchal translucency scans. This research indicates the importance PGS testing of embryos prior to transfer in order to increase the chances of a healthy pregnancy progressing to term and to decrease the chances of miscarriage among couples seeking fertility treatment.
Acknowledgements: The authors would like to thank the staff at CReATe Fertility Centre for their contributions.