Low-molecular-weight heparin in the prevention of unexplained recurrent miscarriage: a systematic review and meta-analysis.

The etiology of recurrent pregnancy loss (RPL) is complex and multifactorial and in half of patients it remains unexplained (U-RPL). Recently, low-molecular-weight heparin (LMWH) has gained increasing relevance for its therapeutic potential. On this regard, the aim of this systematic review and meta-analysis is to analyze the efficacy of low molecular weight heparin (LMWH) from the beginning of pregnancy in terms of live birth rates (LBR) in U-RPL. Registered randomized controlled trials (RCTs) were included. We stratified findings based on relevant clinical factors including number of previous miscarriages, treatment type and control type. Intervention or exposure was defined as the administration of LMWH alone or in combination with low-dose aspirin (LDA). A total of 6 studies involving 1016 patients were included. The meta-analysis results showed that LMWH used in the treatment of U-RPL was not associated with an increase in LBR with a pooled OR of 1.01, a medium heterogeneity (26.42%) and no publication bias. Results of other sub-analyses according to country, treatment type, and control type showed no significant effect of LMWH on LBR in all subgroups, with a high heterogeneity. The results highlight a non-significant effect of LMWH in U-RPL on LBR based on moderate quality evidence.Registration number: PROSPERO: ( https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022326433 ).

To Assess or Not to Assess: Reconsidering Day 3 Embryo Quality in Planned Freeze-All Blastocyst Cycles.

Day 3 embryo quality is a predictor of in vitro fertilization (IVF) success rates in cleavage-stage embryo transfer. However, the association between day 3 embryo quality and clinical outcomes in blastocyst transfer policy is largely unknown. This retrospective study included 1074 frozen-thawed single day 5/6 blastocyst transfers between January 2019 and December 2022. Three groups were assessed depending on whether the transferred blastocyst derived from a top-quality, good-quality, or poor-quality embryo at day 3. The analysis was conducted independently for each blastocyst quality group (top, good, and poor) using multivariable logistic regression. We applied a Factorial Analysis of Mixed Data (FAMD) to reduce the potential collinearity between the covariates used in the model. All the blastocysts included in this study were obtained from the first ICSI freeze-all cycles. The cleavage and blastocysts stages were assessed between 67 ± 0.5 (day 3), 115 ± 0.5 (day 5), and 139 ± 0.5 (day 6) hours post-insemination (hpi), respectively. After adjusting for the day of transfer (day 5 or day 6) and FAMD dimensions, no statistical differences in a ß-HCG, clinical pregnancy, and live birth were observed among the same-quality blastocysts derived from different day 3 embryo quality groups (top = A, good = B, and poor = C). Our findings showed that a day 3 embryo quality assessment may be unnecessary in planned freeze-all blastocyst cycles.

The Promise and Pitfalls of AI-Generated Anatomical Images: Evaluating Midjourney for Aesthetic Surgery Applications.

BACKGROUNDS: The rapid advancement of generative artificial intelligence (AI) systems, such as Midjourney, has paved the way for their use in medical training, producing computer-generated images. However, despite clear disclosures stating that these images are not intended for medical consultations, their accuracy and realism are yet to be thoroughly examined. METHODS: A series of requests were addressed to the Midjourney AI tool, a renowned generative artificial intelligence application, with a focus on depicting appropriate systemic anatomy and representing aesthetic surgery operations. Subsequently, a blinded panel of four experts, with years of experience in anatomy and aesthetic surgery, assessed the images based on three parameters: accuracy, anatomical correctness, and visual impact. Each parameter was scored on a scale of 1-5. RESULTS: All of images produced by Midjourney exhibited significant inaccuracies and lacked correct anatomical representation. While they displayed high visual impact, their unsuitability for medical training and scientific publications became evident. CONCLUSIONS: The implications of these findings are multifaceted. Primarily, the images' inaccuracies render them ineffective for training, leading to potential misconceptions. Additionally, their lack of anatomical correctness limits their applicability in scientific articles. Although the study focuses on a single AI tool, it underscores the need for collaboration between AI developers and medical professionals. The potential integration of accurate medical databases could refine the precision of such AI tools in the future. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Progesterone levels during ovarian stimulation in segmented ART cycles inversely correlate with normalized birthweight of neonates conceived through subsequent frozen-thawed embryo transfer.

PURPOSE: To evaluate the association between serum progesterone (P) at the day of ovulation trigger and neonatal birthweight in singletons born after frozen-thawed embryo transfer in segmented ART cycles. METHODS: A retrospective multicenter cohort study involving data from patients who achieved uncomplicated pregnancy and term delivery of ART-conceived singleton babies following a segmented GnRH antagonist cycle. The main outcome was birthweight's z-score of the neonate. Univariate and multivariate linear logistic regression analyses were made to investigate the relation of z-score with variables inherent to the patient and to the ovarian stimulation. The variable P per oocyte was created by dividing the value of progesterone at ovulation trigger by the number of oocytes retrieved at oocyte retrieval. RESULTS: A total of 368 patients were included in the analysis. At univariate linear regression, the birthweight z-score of the neonate appeared to be inversely related to both P levels at the ovulation trigger (- 0.101, p = 0.015) and P levels per oocyte at trigger (- 1.417, p = 0.001), while it was directly related to the height of the mother (0.026, p = 0.002) and to the number of previous live births (0.291, p = 0.016). In multivariate analysis, both serum P (- 0.1; p = 0.015) and P per oocyte (- 1.347, p = 0.002) maintained the significant inverse association with birthweight z-score after adjusting for height and parity. CONCLUSIONS: Serum progesterone level on the day of ovulation trigger inversely correlates with normalized birthweight of neonates in segmented GnRH antagonist ART cycles.

Fertility Preservation as an Option for Women with Genetic Disorders: Insights from a SWOT Analysis on Elective Oocyte Freezing and Preimplantation Genetic Testing.

This paper uses a SWOT (strengths, weaknesses, opportunities, and threats) analysis to overview the option of fertility preservation in women with genetic diseases, who would later use preimplantation genetic testing for monogenic disorders, in order to not transmit their condition. Strengths associated with elective oocyte freezing are ethical considerations, overall maternal and fetal safety, and effectiveness, if performed at <35 years of age. Weaknesses are related to costs and rare but present (<1-3%) risks of maternal complications. Counselling on fertility management aimed at preventing infertility offers a valuable opportunity, the same as it has been in oncological patients' care. The potentially high percentage of women with genetic conditions who would return to use their frozen oocytes also represents an opportunity together with the minimization of the need for egg donation, which has higher obstetrical risks compared to the use of autologous oocytes. Finally, a threat is represented by the potential psychological distress to young women who could never attempt to become pregnant through preimplantation genetic testing, or do it before any decline in their fertility. Potential unknown future long-term health risks for children conceived after egg vitrification/thawing are also a threat, but current knowledge is reassuring. Altogether, early counselling on the option of fertility preservation should thus be incorporated into standard care of all patients with any genetic condition.

Response to Controlled Ovarian Stimulation Is Not Impaired in Young Patients with a Sarcoma: Results from a Monocentric Case-Control Study.

Sarcomas are relatively common in the young and their treatment can impair fertility. Fertility preservation can be achieved via the cryopreservation of gametes after controlled ovarian stimulation before cancer treatment. A reduced response to hormonal stimulation in patients suffering from certain types of malignancy is reported. The purpose of this study was to assess the performance of oocyte cryopreservation in patients with sarcoma by comparing their outcomes with those of a population without cancer. Patients were matched by age with control women undergoing hormonal stimulation for isolated male factor infertility. The population included 84 women with a sarcoma and 355 controls. In the final analysis, 37 patients with sarcoma were matched in a 1:3 ratio with 109 healthy controls. Patients with sarcoma were generally younger and were stimulated with lower FSH doses. They did not perform worse than controls during stimulation, with an average retrieval of 10.6 oocytes vs. 8.1 in the controls. Linear regression on the number of retrieved mature oocytes confirmed that patients with sarcoma performed comparably to controls. In conclusion, patients with sarcoma can expect retrieval outcomes comparable to those of patients without cancer.

Genetic Variants of Gonadotropins and Their Receptors Could Influence Controlled Ovarian Stimulation: IVF Data from a Prospective Multicenter Study.

BACKGROUND: Specific polymorphisms might influence controlled ovarian stimulation in women undergoing assisted reproductive technologies (ARTs). Data regarding possible interactions of these polymorphisms are still scanty. The aim of this analysis was to evaluate the effect of polymorphisms of gonadotropins and their receptors in women undergoing ART. METHODS: A total of 94 normogonadotropic patients from three public ART units were enrolled. Patients underwent a gonadotropin releasing hormone (GnRH) long down-regulation protocol with a starting dose of 150 IU of recombinant follicular stimulating hormone (FSH) daily. Eight polymorphisms were genotyped. RESULTS: A total of 94 women (mean age 30.71 ± 2.61) were recruited. Fewer fertilized and mature oocytes were retrieved in homozygous carriers of luteinizing hormone/choriogonadotropin receptor (LHCGR) 291 (T/T) than in heterozygous C/T carriers (p = 0.035 and p = 0.05, respectively). In FSH receptor (FSHR) rs6165 and FSHR rs6166 carriers, the ratio between total gonadotropin consumption and number of oocytes retrieved differed significantly among three genotypes (p = 0.050), and the ratio was lower in homozygous A/A carriers than in homozygous G/G and heterozygous carriers. Women who co-expressed allele G in FSHR-29 rs1394205 and FSHR rs6166 and allele C LHCGR 291 rs12470652 are characterized by an increased ratio between total FSH dosage and number of oocytes collected after ovarian stimulation (risk ratio: 5.44, CI 95%: 3.18-7.71, p < 0.001). CONCLUSIONS: Our study demonstrated that specific polymorphisms affect the response to ovarian stimulation. Despite this finding, more robust studies are required to establish the clinical utility of genotype analysis before ovarian stimulation.

Identification of Psychological Profiles of Cancer Patients Undergoing Fertility Preservation Counseling.

Gonadotoxicity is one of the most distressing side effects of cancer treatment. Fertility preservation strategies should be included during the treatment pathway to prevent the risk of infertility, but the decision to preserve fertility often represents a challenging process that carries an emotional decision-making burden. The aim of this study is to characterize the psychological profiles of women undergoing fertility preservation counseling and to better understand their features. Eighty-two female cancer patients were included in the study. They were asked to complete a battery of self-administered tests which evaluated socio-demographic characteristics, defense mechanisms, depression, anxiety, and representations regarding the importance of parenthood. Based on the psychometric variables, cluster analysis identified four groups which showed significantly different combinations of these psychological characteristics. An additional analysis was performed to evaluate if sociodemographic variables were associated with the four groups, but the results did not show significant differences. These results suggest that very diverse psychological profiles may lead cancer patients to attend oncofertility counseling and choose fertility preservation. For this reason, all patients in childbearing age should have the opportunity to receive appropriate fertility preservation counseling in order to make an informed decision that could have an important impact on their long-term quality of life.

Concomitant Autoimmunity in Endometriosis Impairs Endometrium-Embryo Crosstalk at the Implantation Site: A Multicenter Case-Control Study.

Endometriosis and autoimmune diseases share a hyper-inflammatory state that might negatively impact the embryo-endometrium crosstalk. Inflammatory and immune deregulatory mechanisms have been shown to impair both endometrial receptivity and embryo competence at the implantation site. The aim of this study was to investigate the potential additional impact of co-existing autoimmunity in women affected by endometriosis on the early stages of reproduction. This was a retrospective, multicenter case-control study enrolling N = 600 women with endometriosis who underwent in vitro fertilization-embryo transfer cycles between 2007 and 2021. Cases were women with endometriosis and concomitant autoimmunity matched based on age and body mass index to controls with endometriosis only in a 1:3 ratio. The primary outcome was the cumulative clinical pregnancy rate (cCPR). The study found significantly lower cleavage (p = 0.042) and implantation (p = 0.029) rates among cases. Autoimmunity (p = 0.018), age (p = 0.007), and expected poor response (p = 0.014) were significant negative predictors of cCPR, with an adjusted odds ratio of 0.54 (95% CI, 0.33-0.90) for autoimmunity. These results suggest that the presence of concomitant autoimmunity in endometriosis has a significant additive negative impact on embryo implantation. This effect might be due to several immunological and inflammatory mechanisms that interfere with both endometrial receptivity and embryo development and deserves further consideration.

Delayed blastocyst development is influenced by the level of progesterone on the day of trigger.

PURPOSE: To evaluate the association between progesterone (P) level on the day of trigger and time to blastulation in IVF cycles. METHODS: This was a retrospective cohort study with autologous IVF cycles performed at our Institution from January 2019 to December 2021. A total of 1109 IVF cycles were included. The primary outcome was to compare time to blastulation in terms of percentage of expanded (grade 3) blastocysts on day 5 according to progesterone level at trigger. RESULTS: A total of 3517 blastocysts were analyzed. After dividing progesterone level in quartiles (Q1, P < 0.50 ng/ml; Q2 0.50 ng/ml ≤ P ≤ 0.78 ng/ml; Q3, 0.79 ng/ml ≤ P ≤ 1.15 ng/ml; Q4, P > 1.15 ng/ml), we observed a delay in blastocyst development according to the increasing level of progesterone at trigger (analysis by rank, P-value = 0.01). After adjusting for confounding factors at the multivariate analysis, the percentage of day 5 blastocysts was reduced for Q3 (- 13.8%, 95% CI from - 20.5 to - 7.0%, p < 0.001) and Q4 (- 7.7%, 95% CI from - 15.5 to 0.0%, p = 0.05) compared to Q1 (reference). CONCLUSIONS: Progesterone levels on day of trigger correlate to the percentage of expanded (grade 3) blastocysts on day 5 and a delayed blastocyst development day 5 is expected for high progesterone levels.

Treating unexplained recurrent pregnancy loss based on lessons learned from obstetric antiphospholipid syndrome and inherited thrombophilia: A propensity-score adjusted retrospective study.

The efficacy of low molecular weight heparin (LMWH) is well-established in patients with obstetric antiphospholipid syndrome (O-APS). Their role in women with unexplained recurrent pregnancy loss (U-RPL) and late obstetrical complications (intrauterine growth restriction, IUGR and preeclampsia) is controversial. Here we compared rates of miscarriage and late obstetrical complications in RPL patients diagnosed with O-APS (n = 57) or hereditary thrombophilia (n = 25) (both assuming LMWH from the beginning of pregnancy) and in patients with a history of U-RPL (n = 118), assuming or not LMWH, followed at the 'Pregnancy at risk' and 'Recurrent pregnancy loss' outpatient clinics at the San Raffaele Hospital from April 2010 to April 2020. Patients with systemic autoimmune diseases other than primary O-APS were excluded. We tested for bivariate or multivariate associations among adverse pregnancy outcomes, the presence of thrombophilia and LMWH use by using chi-square test, Anova, propensity score adjusted univariate logistic regression and multivariate analysis as appropriate. U-RPL patients assuming LMWH from the beginning of pregnancy (group A) had a significantly lower rate of miscarriage compared to U-RPL patients who were not treated with LMWH (group B) (13 % vs. 41 % respectively, p 0.001) and similar pregnancy rates compared to both O-APS patients with a history of RPL taking LMWH (group C, 18 %) and RPL patients with thrombophilia and treated with LMWH (group D, 16 %). Our data highlight a protective effect of LMWH on miscarriage in patients with a history of U-RPL. In these patients, LMWH seems as effective as in O-APS and hereditary thrombophilia in reducing RPL.

Laparoscopic Oocyte Retrieval and Cryopreservation during Vaginoplasty for Treatment of Mayer-Rokitansky-Kuster-Hauser Syndrome.

In Mayer-Rokitansky-Kuster-Hauser Syndrome (MRKHS) patients who are scheduled for laparoscopic vaginoplasty and have a desire for biological motherhood, we propose that a concomitant laparoscopic oocyte retrieval for cryopreservation is performed. Oocyte retrieval is pursued at the beginning of the laparoscopy. Right and left 5 mm trocars are positioned, through which a 17 G ovum aspiration needle is used for puncture of the right and left ovaries, respectively. To facilitate exposure of the follicles, the ovaries are mobilized and held with laparoscopic forceps. When aspirating multiple follicles near each other, the needle tip is retained in the ovary to reduce the number of times that the ovarian cortex is transfixed and due to the inherent risk of bleeding. Subsequent steps are unchanged compared to the Davydov laparoscopic modified technique for vaginoplasty. Prior to surgery, controlled ovarian stimulation is performed with a gonadotropin hormone-releasing hormone (Gn-RH) antagonist protocol, and the concomitant procedure of oocyte retrieval and vaginoplasty is scheduled 36 h after the final follicular maturation trigger. Follicular fluid is collected in the same 10 mL sterile tubes used during transvaginal oocyte retrieval and transferred in a warming block (37 °C) to the assisted reproduction laboratory, where mature (metaphase II) oocytes are vitrified. In this case, a series of 23 women with MRKH, oocytes were successfully retrieved and cryopreserved in all patients; vaginoplasty was subsequently conducted without modifications, and the inpatient and outpatient postoperative care (day of urinary catheter removal, day of hospital discharge, dilator use, and comfort at follow-up) remained unaffected. One postoperative complication occurred in one patient (fever developing on day 5 post surgery and intraperitoneal fluid detection on transabdominal ultrasound) and resolved after conservative treatment. Rather than performing surgical vaginoplasty and delaying oocyte retrieval in MRKH patients, this approach combines both procedures in a single laparoscopy, thereby minimizing surgical invasiveness and anesthesiologic risks.

Ovarian failure risk in post-pubertal patients with cancer: a prognostic model.

Aim: To develop a predictive model for ovarian failure (OF) after chemotherapy in young post-pubertal women with cancer. Methods: Retrospective, monocentric cohort study including 348 patients referring to the Oncofertility Unit of San Raffaele Hospital (Milan, Italy) from August 2011 to January 2020. A predictive model was constructed by multivariate logistic regression and receiver operating characteristic analysis. Results: Data about menstrual function resumption were available for 184 patients. The best predictive model for OF was identified by the combination of age; number of chemotherapy lines; vincristine, adriamycin, ifosphamide/adriamycin, ifosphamide; capecitabine; adriamycin, bleomycine, vinblastine, doxorubicin (area under the curve = 0.906; CI 95% 0.858-0.954; p = 0.0001). Conclusions: The model predicts the probability of loss of ovarian function at cancer diagnosis and with every change of treatment.

Chemotherapy can reduce fertility in young women surviving cancer. The effects of chemotherapy on ovarian function range from no damage to several degrees of reduced fertility. In some cases, premature menopause can occur. This variability depends on many different individual and treatment-related factors. In this study, we analyzed the outcomes in terms of menses regularity and fertility of 348 oncological patients receiving counseling on fertility at our unit from August 2011 to January 2020. We developed a predictive model to estimate the risk of premature menopause of each patient, to be used at diagnosis and every time a new treatment must be started. This model includes a combination of patient's age, number of lines of chemotherapeutic treatment, and three chemotherapy schedules commonly used in young patients with cancer. It allows an improved counseling on fertility, and it can aid decision making regarding fertility preservation strategies for each patient.

The neglected members of the family: non-BRCA mutations in the Fanconi anemia/BRCA pathway and reproduction.

BACKGROUND: BReast CAncer (BRCA) genes are extensively studied in the context of fertility and reproductive aging. BRCA proteins are part of the DNA repair Fanconi anemia (FA)/BRCA pathway, in which more than 20 proteins are implicated. According to which gene is mutated and which interactions are lost owing to the mutation, carriers and patients with monoallelic or biallelic FA/BRCA mutations exhibit very different phenotypes, from overt FA to cancer predisposition or no pathological implications. The effect of the so far neglected non-BRCA FA mutations on fertility also deserves consideration. OBJECTIVE AND RATIONALE: As improved treatments allow a longer life expectancy in patients with biallelic FA mutations and overt FA, infertility is emerging as a predominant feature. We thus reviewed the mechanisms for such a manifestation, as well as whether they also occur in monoallelic carriers of FA non-BRCA mutations. SEARCH METHODS: Electronic databases PUBMED, EMBASE and CENTRAL were searched using the following term: 'fanconi' OR 'FANC' OR 'AND' 'fertility' OR 'pregnancy' OR 'ovarian reserve' OR 'spermatogenesis' OR 'hypogonadism'. All pertinent reports in the English-language literature were retrieved until May 2021 and the reference lists were systematically searched in order to identify any potential additional studies. OUTCOMES: Biallelic FA mutations causing overt FA disease are associated with premature ovarian insufficiency (POI) occurring in the fourth decade in women and with primary non-obstructive azoospermia (NOA) in men. Hypogonadism in FA patients seems mainly associated with a defect in primordial germ cell proliferation in fetal life. In recent small, exploratory whole-exome sequencing studies, biallelic clinically occult mutations in the FA complementation group A (Fanca) and M (Fancm) genes were found in otherwise healthy patients with isolated NOA or POI, and also monoallelic carrier status for a loss-of-function mutation in Fanca has been implicated as a possible cause for POI. In those patients with known monoallelic FA mutations undergoing pre-implantation genetic testing, poor assisted reproduction outcomes are reported. However, the mechanisms underlying the repeated failures and the high miscarriage rates observed are not fully known. WIDER IMPLICATIONS: The so far 'neglected' members of the FA/BRCA family will likely emerge as a relevant focus of investigation in the genetics of reproduction. Several (rather than a single) non-BRCA genes might be implicated. State-of-the-art methods, such as whole-genome/exome sequencing, and further exploratory studies are required to understand the prevalence and mechanisms for occult FA mutations in infertility and recurrent miscarriage.

Anti-Müllerian hormone concentration as an indicator of female general health status: a cross-sectional study.

RESEARCH QUESTION: To evaluate the correlation between clinical and hormonal parameters and comorbidity burden in Caucasian women presenting for fertility treatment. DESIGN: Monocentric cross-sectional study including a cohort of 3163 Caucasian women seeking medical care for fertility treatment. All patients underwent centralized laboratory testing for hormonal assessment. Complete clinical and laboratory data from the entire cohort were retrospectively analysed. Comorbidity burden score was assessed by the Charlson Comorbidity Index (CCI; categorized as 0 versus 1 versus ≥2). RESULTS: Descriptive statistics and regression models tested the associations between clinical and laboratory parameters and CCI. Among the entire cohort of patients, a CCI = 0 was found in 2977 women (94.1%), and CCI = 1 and CCI ≥2 were found in 113 (3.6%) and 73 (2.3%) patients, respectively. Age (P = 0.009), gravidity (P = 0.001), anti-Müllerian hormone (AMH, P < 0.001) and TSH (P = 0.003) values were significantly different among CCI groups. In regression models, age at presentation and AMH emerged as independent indicators of CCI ≥ 1. Age at presentation <36 years (odds ratio [OR] 1.742, 95% confidence interval [CI] 1.284-2.364) and an AMH concentration ≤2.3 ng/ml (OR 1.864, 95% CI 1.29-2.69) were the most informative cut-off values for CCI ≥ 1 in the study population. CONCLUSIONS: A younger age at presentation and lower AMH concentrations are significant independent indicators of decreased general health in women requiring clinical evaluation for fertility treatment. As observed for sperm parameters in men, AMH might serve as a proxy of women's general health status.

Concomitant autoimmunity may be a predictor of more severe stages of endometriosis.

Pathogenesis of endometriosis is still unclear and a role of both innate and adaptive immune system has been postulated. Some recent findings have revealed an increased risk to have concomitant autoimmune disease in women with endometriosis, but no study so far has investigated whether this association could affect endometriosis severity and stage. We retrospectively reviewed medical patients' notes of women with a confirmed diagnosis of endometriosis who referred to our endometriosis outpatient clinic between January 2015 and December 2019. Cases (endometriosis and an autoimmune disease) were matched in a 1:3 ratio by age and study period with controls (endometriosis without history of autoimmunity). At univariate logistic analysis, concomitant autoimmunity (OR 2.63, 95% CI 1.64-4.21, p < 0.001) and the number of laparoscopic procedures performed (OR 2.81, 95% CI 1.45-5.43, p = 0.002) emerged as factors significantly associated with the likelihood of stage IV endometriosis. In the multivariate logistic regression model, concomitant autoimmunity remained a significant predictor of stage IV endometriosis (OR 2.54, 95% CI 1.57-4.10, p = 0.004), whereas the association between the number of laparoscopic procedures performed and stage IV endometriosis was found to be of borderline-significance (OR 2.70, 95% 1.37-5.30, p = 0.050). Our findings suggest that endometriosis is more severe in patients who are also affected by autoimmune disturbances after controlling for relevant confounders.

Risk Factors for Monozygotic Twins in IVF-ICSI Cycles: a Case-Control Study.

In vitro fertilization (IVF) is associated with a higher incidence of monozygotic twin pregnancies, which are known to be burdened by a higher risk of main obstetric complications. The reasons behind this association are still unclear. In the present study, we therefore investigate the risk factors for monozygotic twinning in pregnancies achieved by IVF. We conducted a multicenter retrospective case-control study. All IVF cycles performed between 2014 and 2019 at the infertility units of two Italian academic institutes were retrospectively reviewed. Only pregnancies obtained with single embryo transfer were eligible. A total of 50 monozygotic twin pregnancies (cases) were identified and matched in a 1:5 ratio to 250 singleton pregnancies (controls) by study center and study period. Monozygotic twin pregnancies were diagnosed by ultrasound. Women experiencing miscarriage could be included provided that the pregnancy loss occurred after a definitive diagnosis of monozygotic twin pregnancy. Demographic, clinical, and embryological characteristics were retrieved from patients' charts. Overall, the incidence of monozygotic twin pregnancies was 1.2% (50 out of 4016 single embryo transfers). At univariate analyses, statistically significant differences emerged for BMI, peripheral levels of estradiol and progesterone at the time of hCG administration, total number of retrieved suitable oocytes, freezing-thawing cycles, and assisted hatching. After performing a multivariate logistic analysis, only assisted hatching remained significantly associated with monozygotic twinning (adjusted odds ratio 2.32, 95%CI 1.03-5.25). Blastomere separation during the passage through this artificial hole or interference with the signaling pathway within the embryo could be the mechanisms involved.

Frozen IVF Cycles to Circumvent the Hormonal Storm on Endometrium.

Controlled ovarian hyperstimulation (COH) determines an anticipation of endometrial maturation and a premature occurrence of the implantation window, as shown by histological, histochemical, and molecular studies and indirectly by clinical trials. There is growing agreement that in patients hyper-responding to COH and in those undergoing transfer at the blastocyst stage, deferring the transfer in a subsequent frozen cycle could increase pregnancy outcomes. For blastocysts, implantation after a fresh transfer may be limited as the implantation window is already closed while, in hyper-responders to COH, the anticipation magnitude could be more marked thus hampering implantation also for cleavage-stage embryos. Research should focus in depth on pregnancy outcomes and on the most suitable modality to prepare the endometrium for frozen transfers.