Researcher:
Kalafat, Erkan

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Faculty Member

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Erkan

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Kalafat

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Kalafat, Erkan

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2021 - 202340

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    Point of care ultrasound vs. routine third trimester ultrasound - undiagnosed breech presentation
    (Wiley, 2022) Knights, Samantha; Prasad, Smriti; Dadali, Anahita; Harlow, Francoise; Khalil, Asma; N/A; Kalafat, Erkan; Faculty Member; School of Medicine; 197389
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    Oral gonadotropin-releasing hormone antagonists in the treatment of uterine myomas: a systematic review and network meta-analysis of efficacy parameters and adverse effects
    (Elsevier Science Inc, 2022) Telek, Savcı Bekir; Gürbüz, Zeynep Umay; Kalafat, Erkan; Ata, Mustafa Barış; Undergraduate Student; Faculty Member; Faculty Member; School of Medicine; School of Medicine; School of Medicine; Koç University Hospital; N/A; 197389; 182910
    Objective: The aim of this systematic review is to gather and synthesize evidence regarding the use of oral gonadotrophin-releasing hormone (GnRH) antagonist for the treatment of bleeding associated with uterine myomas. Data Sources: Web of Science, and MEDLINE databases were searched electronically on March 5, 2021, using combinations of the relevant Medical Subject Headings terms and keywords. The search was restricted to the English language and to human studies. Methods of Study Selection: Only randomized controlled trials involving patients with heavy menstrual bleeding associated with uterine myomas treated with different doses of oral nonpeptide GnRH antagonists with or without add-back therapy were included. Studies comparing oral nonpeptide GnRH antagonists with treatments other than placebo were also excluded. Tabulation, Integration, and Results: A total of 5 randomized trials including 2463 women were included in the analyses. Included studies were found to be at low risk of bias. When treatments were compared against placebo, the top 3 treatments for bleeding suppression were elagolix 600 mg, 400 mg, and 200 mg without add-back. Elagolix 600 mg without add-back therapy had a significantly higher risk of amenorrhea than lower doses of elagolix with and without add-back and relugolix as well. Uterine volume changes were more pronounced in therapies without add-back. All treatments were associated with significantly improved quality of life scores, both for myoma symptom-related and overall health-related scores. With the exception of relugolix with high-dose add-back, all treatments significantly increased low-density lipoprotein (LDL) levels. Again, all treatment modalities except for elagolix 200 mg without add-back significantly increased LDL-to-HDL ratio. The increase was highest for treatment without add-back therapy. Conclusion: Oral GnRH antagonists seem to be effective for myoma-associated bleeding and for improving quality of life. The safety profile is acceptable for short-term use, but lipid metabolism is affected. (C) 2022 Published by Elsevier Inc. on behalf of AAGL.
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    Recurrent implantation failure: a plea for a widely adopted rational definition
    (Elsevier, 2022) Somigliana, Edgardo; Busnelli, Andrea; Vigano, Paola; N/A; Kalafat, Erkan; Ata, Mustafa Barış; Faculty Member; Faculty Member; School of Medicine; School of Medicine; 197389; 232576
    Most proposed definitions of recurrent implantation failure (RIF) are based on clinical judgement, probably affected by patients’ demands. They are not based on robust statistical considerations. As a result, a diagnosis of RIF is commonly made too early, exposing couples to the risk of overdiagnosis and overtreatment. However, the situation is changing, and three statistical approaches have recently been proposed. The first is a probability model based on the chances of success per cycle and suggests for the definition three failed oocyte retrieval cycles with all embryos being transferred in women younger than 40 years of age. The second approach suggests an individualized diagnosis that takes into consideration multiple factors, while the third is also based on individualization but mainly relies on anticipated euploidy rates across the female age range. All these approaches have their pros and cons. Regardless of the specific peculiarities, they represent steps in the right direction, with the intent of providing a statistically sound definition. However, these attempts will not be useful unless endorsed by the scientific community in general. There is a pressing need for a rigorous and shared definition of RIF that will be widely accepted by researchers, scientific societies and other stakeholders, including patients.
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    COVID-19 vaccination in pregnancy-number needed to vaccinate to avoid harm
    (Elsevier, 2021) Magee, Laura A.; von Dadelszen, Peter; Duncan, Emma L.; O'Brien, Pat; Morris, Edward; Heath, Paul; Khalil, Asma; N/A; Kalafat, Erkan; Faculty Member; School of Medicine; 197389
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    First-trimester choroid plexus to lateral ventricle disproportion and prediction of subsequent ventriculomegaly
    (Wiley, 2023) Prasad, Smriti; Fabrizio, C. Di; Eltaweel, Nashwa; Khalil, Asma; N/A; Kalafat, Erkan; Faculty Member; School of Medicine; 197389
    Objective: ventriculomegaly can be associated with long-term neurodevelopmental impairment. The prenatal diagnosis of ventriculomegaly is most often made at the routine second trimester anomaly scan. The value of first trimester ultrasound has expanded to early diagnosis and screening of fetal abnormalities. The objective of this study was to assess the predictive accuracy of first trimester choroid plexus to head/ventricle ratios for development of ventriculomegaly at a later gestation. Methods: this was a case-control study of fetuses with isolated ventriculomegaly diagnosed after 16 weeks' gestation. The control group included normal fetuses (without ventriculomegaly). The exclusion criteria included aneuploidy, genetic syndromes or other brain abnormalities. Stored 2D first trimester ultrasound images were blindly analyzed offline and fetal biometry measured in axial view of the fetal head. The ratios of choroid plexus to lateral ventricle area (PA/VA), choroid plexus to lateral ventricle length (PL/VL), choroid plexus to lateral ventricle diameter (PD/VD), choroid plexus area to biparietal diameter (PA/BPD) and choroid plexus area to head circumference (PA/HC) were measured at 11-13+6 weeks' gestation. Intra- and inter-observer variability of these fetal head biometry parameters at 11-13+6 weeks' gestation were assessed in 20 normal fetuses using intra-class coefficients with 95% confidence intervals. The accuracy of first-trimester biometric measurements for prediction of ventriculomegaly was assessed using the area under the ROC curves (AUC). Results: the analysis included 683 singleton pregnancies; of which 102 fetuses were diagnosed with ventriculomegaly. The ventriculomegaly was mild in the majority (n=86; 84.3%) of cases, while it was severe in 16 (15.7%) fetuses. All first trimester fetal choroid plexus to ventricle/head ratios were significantly lower in the ventriculomegaly cases than in controls (p<0.05 all) with good inter- and intra-observer agreement (>0.95 for the majority of the fetal head biometry assessed). After adjusting for crown-rump length, both PL/VL ratio (AUC 0.87, 95% CI 0.73-0.98) and PA/VA ratio (AUC 0.90, 95% CI 0.82-0.98) showed good predictive accuracy for severe ventriculomegaly. PA/BPD ratio (AUC 0.73, 95% CI 0.54-0.90) had modest predictive ability, which was significantly lower than prediction using PA/VA ratio (P=0.003 and P=0.001, respectively). The predictive accuracy of PD/VD ratio was low with an AUC of 0.65 (95% CI 0.46- 0.84). Optimism adjusted AUC values obtained after cross-validation showed that PA/VA ratio offered the highest predictive accuracy with an AUC of 0.90 (95% CI: 0.82-0.98), followed by PL/VL ratio (AUC 0.87, 95% CI 0.73-0.98), PA/BPD ratio (AUC 0.73, 95% CI 0.54-0.90), and PD/VD ratio (AUC 0.65, 95% CI 0.47-0.84). Optimism-adjusted AUC values obtained after cross-validation showed that PA/VA ratio offered the highest predictive accuracy for mild ventriculomegaly with an AUC of 0.83 (95% CI 0.78-0.88), followed by PL/VL ratio (AUC 0.82, 95% CI 0.76-0.88), PA/BPD ratio (AUC 0.75, 95% CI 0.68-0.81), and PD/VD ratio (AUC 0.74, 95% CI 0.67-0.80). Calibration plots show both PA/VA and PL/VL ratios have good calibration CONCLUSION: First-trimester prediction of ventriculomegaly using fetal choroid plexus to ventricle ratios appears promising. Future prospective studies are needed to validate the predictive accuracy of these ultrasound markers as a screening tool for ventriculomegaly.
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    Are live birth rate and obstetric outcomes different between immediate and delayed embryo transfers following a freeze-all cycle? a retrospective study combined with a meta-analysis
    (Oxford Univ Press, 2021) N/A; N/A; N/A; N/A; N/A; N/A; Yıldız, Şule; Türkgeldi, Engin; Kalafat, Erkan; Gökyer, Dilan; Keleş, İpek; Ata, Mustafa Barış; Faculty Member; Faculty Member; Faculty Member; Undergraduate Student; Doctor; Faculty Member; School of Medicine; School of Medicine; School of Medicine; School of Medicine; N/A; School of Medicine; Koç University Hospital; 134205; 329649; 197389; N/A; N/A; 182910
    Study Question: Do livebirth rate (LBR), obstetric and perinatal outcomes vary between frozen embryo transfers (FET) in the first or subsequent menstrual cycles following a freeze-all approach? Summary Answer: Immediate FET has a higher LBR and similar perinatal outcomes than delayed FET. Quantitative synthesis of available literature shows an increased LBR with immediate transfer. What is Known Already: Whether FET should be done in the first menstrual cycle following oocyte collection (OC) is controversial and the duration of a possible detrimental effect of supraphysiological sex steroid levels on pregnancy outcome is unknown. A multinational survey centers showed that, 61% of clinicians prefer to wait for a washout period before proceeding to FET, even after a failed fresh embryo transfer. Limited number of studies compared FET in the first menstrual cycle with delayed FET in a subsequent cycle with varying results. There is limited data on obstetric outcomes of pregnancies resulting from FET in the first menstrual cycle. Study Design, Size, Duration: 198 women who underwent a freeze-all cycle followed by FET between July 2017 and June 2020 were included. 119 FET in the first menstrual cycle (<30 days from oocyte collection) and 79 FET in subsequent cycles (>30 days from oocyte collection) were retrospectively compared. MEDLINE was searched on 01 January 2021 using relevant keywords. Cohort studies comparing immediate versus delayed transfer following freeze all cycles were included and quantitative summary for LBR was obtained. Participants/Materials, Setting, Methods: Freeze-all was undertaken when (i) the woman is deemed to be at high risk for OHSS, (ii)serum progesterone level is > 1.5 ng/ml on the day of trigger, (iii)preimplantation genetic testing is planned, (iv)the woman will undergo surgery prior to ET, (v)couple preference. Main Results and the Role of Chance: Baseline characteristics were similar between the groups except for antral follicle count (22 vs 18, MD = 5, 95% CI = 0 to 8), and number of metaphase-two oocytes (13 vs 10, MD = 3, 95% CI = 1 to 6) all of which were significantly higher in the immediate transfer group. Clinical pregnancy rate (CPR) per ET was similar in two groups (50.4% vs 44.3%, RR = 1.14, 95% CI = 0.84 to 1.54). Miscarriage rate per pregnancy was significantly lower (12.3 vs 31.1, RR = 0.40, 95% CI = 0.19 to 0.84) and LBR per ET was significantly higher (42.9 vs 26.6, RR = 1.61, 95% CI = 1.06 to 2.46) in the immediate transfer group. Median gestational age at delivery was similar (267.5 (262.5–273) vs 268 (260–271.5) days, MD = 1.00, 95% CI= –4.00 to 5.00). Median birthweight was significantly higher in the delayed transfer group (3520 vs 3195 grams, MD= –300, 95% CI= –660 to –20 grams). Birthweight percentile, height at birth and head circumference were similar between groups. Literature search revealed 1712 studies from which nine were eligible for quantitative summary. Cumulative risk ratio showed a 10% increase in LBR with immediate transfer ompared to delayed transfer (RR = 1.10, 95% CI = 1.01 – 1.20, I2=67%, 17369 embryo transfers). Limitations, Reasons for Caution: Our study is limited by its retrospective design and relatively limited sample size for multivariate analyses. Yet, it is reassuring that the majority of our findings are consistent with previous publications. Wider Implications of the Findings: The hypotheses generated by our retrospective findings, i.e., FET in the immediate menstrual cycle resembling fresh ETs with strong trends towards lower birthweight and lower incidence of preeclampsia is noteworthy for the design of future studies, and these outcomes should be followed and reported.
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    Increased incidence of first-trimester miscarriage during the COVID-19 pandemic
    (2021) Saçıntı, Koray G.; Şükür, Y. E.; Koç, A.; N/A; Kalafat, Erkan; Faculty Member; School of Medicine; 197389
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    Clinical severity of SARS-CoV-2 infection among vaccinated and unvaccinated pregnancies during the Omicron wave
    (Wiley, 2022) Ilter, P. Birol; Prasad, S.; Mutlu, M. A.; O'Brien, P.; von Dadelszen, P.; Magee, L. A.; Tug, N.; Khalil, A.; N/A; Berkkan, Metehan; Çelik, Ebru; Ata, Mustafa Barış; Yıldız, Şule; Türkgeldi, Engin; Kalafat, Erkan; Undergraduate Student; Faculty Member; Faculty Member; Faculty Member; Faculty Member; Faculty Member; Faculty Member; School of Medicine; School of Medicine; School of Medicine; School of Medicine; School of Medicine; School of Medicine; School of Medicine; N/A; 116631; 182910; 199792; 134205; 329649; 197389
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    Effect of the endometrial thickness on the live birth rate: insights from 959 single euploid frozen embryo transfers without a cutoff for thickness
    (Elsevier, 2023) Liñán, Alberto; Ruíz, Francisco; Melado, Laura; Bayram, Asina; Elkhatib, Ibrahim; Lawrenz, Barbara; Fatemi, Human M.; N/A; Ata, Mustafa Barış; Kalafat, Erkan; Faculty Member; Faculty Member; School of Medicine; School of Medicine; 182910; 197389
    Objective: to investigate whether endometrial thickness (ET) independently affects the live birth rate (LBR) after embryo transfer. Design: retrospective study. Setting: private assisted reproductive technology center. Patient(s): a total of 959 single euploid frozen embryo transfers. Intervention(s): vitrified euploid blastocyst transfer. Main outcome measure(s): live birth rate per embryo transfer. Result(s): the conditional density plots did not demonstrate either a linear relationship between the ET and LBR or a threshold below which the LBR decreased perceivably. Receiver operating characteristic curve analyses did not suggest a predictive value of the ET for the LBR. The area under the curve values were 0.55, 0.54, and 0.54 in the overall, programmed, and natural cycle transfers, respectively. Logistic regression analyses with age, embryo quality, day of trophectoderm biopsy, body mass index, and ET did not suggest an independent effect of the ET on the LBR. Conclusion(s): we did not identify a threshold of the ET that either precluded live birth or under which the LBR decreases perceivably. Common practice of cancelling embryo transfers when the ET is <7 mm may not be justified. Prospective studies, in which the management of the transfer cycle would not be altered by ET, would provide higher-quality evidence on the subject.
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    Quality or quantity? pitfalls of assessing the effect of endometrial thickness on live birth rates
    (Elsevier Science Inc, 2022) N/A; Ata, Mustafa Barış; Kalafat, Erkan; Faculty Member; Faculty Member; School of Medicine; School of Medicine; 182910; 197389
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