Diagnostic hysteroscopy with endometrial fundal incision may improve reproductive outcomes in oocyte recipients after implantation failure.

OBJECTIVE: This study aimed to investigate whether hysteroscopy plus endometrial fundal incision (EFI) with endoscopic scissors can improve reproductive outcomes in oocyte recipients who have failed in their first egg donation cycle. METHODS: This was a prospective study (2014-2022) conducted in Assisting Nature Centre Reproduction and Genetics, Thessaloniki Greece, IVF Unit. The study population consisted of oocyte recipients with implantation failure in their first embryo transfer (ET) with donor eggs. All the recipients underwent routine evaluation during their early follicular phase, 1-3 months before the start of a new cycle with donor oocytes and were eligible to undergo EFI. RESULTS: During the study period, 218 egg recipients underwent egg donation; 126 out of 218 oocyte recipients (57.8%) did not achieve a live birth at the 1st ET. 109 of them had surplus embryos cryopreserved and underwent a second ET; 50 women consented for EFI. Both groups were similar in terms of age, years of infertility, duration of estrogen replacement protocol and number of transferred blastocysts (p>0.05). In the EFI group, 60% had normal intrauterine cavity, while 40% had minor anomalies. The pregnancy test was positive in 46% (n=23/50) in the EFI group compared with 27.1% (n=16/59) in the control group (p=0.04). Moreover, live birth rates were higher in the EFI group compared to the control group (38.0% vs. 20.3%; p=0.04). CONCLUSIONS: The findings of our study indicate that in oocyte recipients after implantation failure, diagnostic hysteroscopy plus EFI prior to subsequent ETmay increase pregnancy and live birth rates.

Fertilización asistida con óvulos propios en mujeres mayores de 40 años: indicaciones y resultados

Las mujeres posponen su maternidad por el deseo de superación personal y profesional. Se conoce que la cantidad y calidad de los óvulos por ciclo dependen de la edad de la paciente. Las tasas de éxito en tratamientos de reproducción asistida disminuyen con la edad, especialmente después de los 40 años. Se observan tasas más altas de nacidos vivos en mujeres más jóvenes y las tasas disminuyen significativamente en mujeres mayores debido a la disminución de la fertilidad y el aumento de abortos espontáneos. Por ello, la edad es crucial al evaluar la posibilidad de un embarazo exitoso mediante tratamientos de reproducción asistida (TRA). Las indicaciones para realizar fertilización in vitro (FIV) con óvulos propios en mujeres mayores de 40 años incluyen iniciar lo más pronto procedimientos de alta complejidad, buena evaluación de la reserva ovárica con análisis de la hormona antimülleriana y conteo de folículos antrales para realizar asesoramiento genético, proponer FIV-inyección intracitoplasmática de espermatozoides (ICSI) antes de los 44 años, generar expectativas realistas y realizar consentimiento informado, con estadisticas propias. En la REDLARA, de todos los procedimientos de FIV-ICSI, el 34% de las pacientes tienen más de 40 años; se prefiere transferir blastocistos con prueba genética preimplantacional de aneuploidías (PGT-A) para seleccionar embriones euploides. Las tasas de éxito son bajas, inclusive cuando son tasas de embarazo por transferencia de un embrión en el grupo de mujeres ≥ 40 años (18,2% sin PGT, 42,7% con PGT en el IMRCRP). Se recomienda acumular óvulos o embriones realizando múltiples estimulaciones ováricas. Se debe optar por transferir un solo embrión para evitar complicaciones obstétricas con embarazos múltiples en pacientes ≥ 40 años, por el alto riesgo debido a la edad.

Women postpone motherhood because of their desire for personal and professional improvement. It is known that the quantity and quality of oocytes per cycle depends on the patient's age. Success rates in assisted reproduction treatments decrease with age, especially after 40 years of age. Higher live birth rates are observed in younger women, and rates decrease significantly in older women due to decreased fertility and increased miscarriages. Therefore, age is crucial when assessing the possibility of a successful pregnancy through assisted reproductive treatments (ART). The indications to perform in vitro fertilization (IVF) with own ovules in women older than 40 years include starting as soon as possible highly complex procedures, good evaluation of ovarian reserve with antimüllerian hormone analysis (AMH) and antral follicle count (AFC) for genetic counseling, proposing IVF-intracytoplasmatic sperm injection (ICSI) before the age of 44 years, generating realistic expectations and informed consent, with own statistics. At REDLARA, of all IVF-ICSI procedures, 34% of patients are over 40 years old; preference is given to transfer blastocysts with preimplantation genetic testing for aneuploidy (PGT-A) to select euploid embryos. Success rates are low, even when they are pregnancy rates per embryo transfer in the group of women ≥ 40 years (18.2% without PGT, 42.7% with PGT in IMRCRP). It is recommended to bank ovules or embryos by performing multiple ovarian stimulations. A single embryo transfer should be chosen to avoid obstetric complications with multiple pregnancies in patients ≤ 40 years, because of the high risk due to age.

Influence of weaning management at 30, 75 and 180 days of age on non-esterified fatty acids and reproductive performance in beef cows.

This study aimed to investigate the effect of age at weaning of calves on non-esterified fatty acids (NEFA) and reproductive parameters of beef cows. Animals (n = 65) were randomly assigned to three treatments after calving: hyper-early weaning (W30) at 32 ± 0.89 days, early weaning (W75) at 77 ± 0.95 days, and conventional weaning (W180) at 183 ± 0.82 days. Body weight (BW) and body condition score (BCS) were evaluated at parturition (AP) and at 30, 45, 64, 81, 100 and 115 days postpartum (dPP). Blood samples were collected to analyze NEFA levels and progesterone (P4) at 30, 45, 64 and 81 dPP. Higher BW and BCS were observed from 64 to 115 dPP in W30 cows than W180 ones (p < 0.05). Cows subjected to W30 condition had higher levels of NEFA at 30 dPP compared to 64 and 81 dPP (p < 0.05). We also observed that cows from W180 group showed decreased levels of NEFA at 30 dPP compared to 45 (p < 0.01) and 64 dPP (p < 0.05). The highest P4 level was observed at 64 dPP in W30 cows compared to W75 and W180 (p < 0.05). We also observed higher CR of W30 (86%) compared to W180 (47%) at 45 dPP (p < 0.05). The overall pregnancy rate (PR) was higher for W30 (95.5%) than W180 (73.9%). In addition, higher BW at calving and P4 levels at 30 dPP were positively correlated with the possibility of pregnancy (p < 0.05). Improvement in BW and BCS were observed in cows subjected to hyper-early weaning management. However, levels of NEFA decreased as the postpartum period progressed. We concluded that cows who weaned calves hyper-early have greater chances of increasing cyclicity and PRs.

Luteal function in cyclic goats treated with human chorionic gonadotropin administered by intramuscular or intravaginal routes at the time of artificial insemination.

Human chorionic gonadotropin (hCG) has been used to improve goats reproductive efficiency. This study aimed to (i) evaluate if hCG administered by the intramuscular (i.m.) or intravaginal (i.vag.) route can be detected by a rapid ß-hCG test in blood plasma samples and (ii) document ovarian effects of hCG administered by both routes at the time of artificial insemination (AI) performed 60 h after oestrus synchronization in goats. Twenty-two Alpine goats received two i.m. injections of 30 µg of d-cloprostenol (Prolise®, Tecnopec, São Paulo, Brazil) 7.5 days apart. One day after the onset of oestrus (at the time of AI), the goats were randomly allocated to one of the three groups that received: control (n = 7): 0.3 ml of saline solution intravaginally; hCGi.m. (n = 7): 300 IU of hCG (Vetecor®; Hertape-Calier, São Paulo, Brazil) i.m. and hCGi.vag. (n = 8): 300 IU of hCG deposited intravaginally. Blood samples were drawn at -1, 3, 6, 9 and 24 h after as well as on days 3, 7, 10, 13, 17 and 21 after hCG treatment/AI. All animals tested negative for hCG (ECO Diagnóstica, Corinto, Brazil) at -1 h, and all control animals tested negative throughout the entire blood collection period. All hCGi.m. animals tested positive from 3 h until D3 post-AI but only 50% of hCGi.vag. goats tested positive during the present study. In all animals studied, mean circulating P4 concentrations increased (p < .05) from D3 to D7 after AI and then declined (p < .05) from D10 to D17 in control and hCGi.m. groups and from D17 to D21 in the hCGi.vag. group. Total cross-sectional luteal area (CLA), mean colour Doppler area (DA), DA/CLA, mean high-velocity Doppler area and HVDA/CLA all declined (p < .05) by D17-D21 in all animals studied. In summary: (i) human chorionic gonadotropin could consistently be detected in blood samples using the rapid ß-hCG test only in the hCGi.m. group; and (ii) there were no significant differences in the mean pregnancy rate, circulating P4 concentrations and various luteal parameters studied among Control, hCGi.m. and hCGi.vag. dose.

Processos que afetam a taxa de gestação pós-inovulação do embrião equino / Processes that affect pregnancy rate after embryo transfer

A transferência de embriões equinos é uma biotecnologia que traz inúmeros benefícios reprodutivos para um haras. Entretanto, os índices reprodutivos obtidos numa estação de monta podem ser afetados por diversos fatores que interferem tanto na recuperação embrionária que normalmente são relacionados à doadora de embriões, quanto na taxa de gestação na receptora de embriões. O objetivo do presente artigo foi revisar os fatores relacionados à receptora de embriões em programas de transferência de embriões equinos.(AU)

Equine embryo transfer is a biotechnology that brings reproductive benefits to a stud farm. However, the reproductive rates obtained in a breeding season can be affected by several factors that interfere both in the embryonic recovery that are normally related to the embryo donor, and in the pregnancy rate in the embryo recipient. The aim of this article was to review the factors related to the recipient of embryos in equine embryo transfer programs.(AU)

Effect of thyroid function on assisted reproduction outcomes in euthyroid infertile women: A single center retrospective data analysis and a systematic review and meta-analysis.

Background: The influence of thyroid-stimulating hormone (TSH) on gestational outcomes have been studied and checked whether differing TSH levels are relevant on human reproduction outcomes. International guidelines recommend TSH values <2.5 mIU/L in women trying to conceive, since values above this level are related to a higher frequency of adverse reproductive outcomes. This study aimed to evaluate whether TSH values correlate with different gestational outcomes in euthyroid infertile women without autoimmune thyroid disease. Methods: A retrospective cohort study was conducted involving 256 women who underwent in vitro fertilization (IVF) treatment. The participants were divided into two groups: TSH 0.5-2.49 mIU/L (n=211) and TSH 2.5-4.5 mIU/L (n=45). The clinical data, hormonal profiles and reproductive outcomes were compared between groups. Additionally, a systematic review with meta-analysis following the PRISMA protocol was carried out in PubMed/MEDLINE, EMBASE, and SciELO, with no time or language restrictions, for articles comparing TSH groups named "low TSH" (<2,5 mIU/L) and "high TSH" (≥2.5 mIU/L). A meta-analysis of proportions was performed with pooled estimates expressed as relative risk (RR) of events and a random effects model. Results: Age, BMI, free thyroxine levels (FT4) hormonal profile and IVF outcomes were not different between groups, neither gestational outcomes (p=0.982). Also, no difference was observed when the TSH and FT4 levels were compared between patients with positive or negative gestational outcomes (p=0.27 and p=0.376). Regarding the systematic review with meta-analysis, 17 studies from 2006 to 2022 were included, and added by this original retrospective research comprising 13.247 women undergoing IVF. When comparing the proportions of clinical pregnancy between the TSH groups, no significant difference was found (RR 0.93, 95% CI 0.80-1.08), with high between studies heterogeneity (I²: 87%; τ2: 0.0544; p<0.01). The number of deliveries was not significantly different between groups, despite a trend towards higher frequency in the high-TSH group (RR 0.96, 95% CI 0.90-1.02). Conclusion: Variation in TSH levels within the normal range was not associated with pregnancy and delivery rates in women, without autoimmune thyroid disease, who underwent IVF treatment. Systematic review registration: https://www.crd.york.ac.uk/prospero/, identifier CRD 42022306967.

Developmental Potential of embryos does not Impact Pregnancy Outcomes, but it Affects Live Birth Rates in Frozen Blastocyst Transfer Cycles.

OBJECTIVE: This study aimed to determine whether or not developmental potential impacts clinical outcomes, when good grade blastocysts from Days 5 and 6 were transferred in frozen embryo transfer (FET) cycles. METHODS: 654 women, including 460 (70.33%) on Day 5 and 194 (29.66%) on Day 6 were analyzed, in which 905 Day-5 and 274 Day-6 blastocysts were transferred. Only grade AA, AB, BA, BB quality and expansion grade between 3-6 (Gardner grading system) blastocysts survived and were included. RESULTS: The implantation rate was higher, 41.9% (379/905) in normal Day-5 compared to delayed Day-6 blastocyst transfers - 36.5% (100/274), but not significant (p=0.1). The clinical pregnancy rate was similar and not significant (p=0.4) in normal Day-5 (32.4%), compared to delayed Day-6 (35%). Miscarriage rates were higher in normal Day-5 (13.3%) compared to delayed Day-6 (6.3%) blastocyst transfers but were not significant (p=0.06). On the other hand, the biochemical pregnancy rate was significantly higher (p=0.001) in the delayed Day-6 blastocysts (16.7%) transfer group compared to patients with normal Day-5 (2.4%) blastocyst transfers. Two patients had ectopic pregnancies from the delayed Day-6 blastocyst transfer group. Live-Birth rates were significantly higher in Day-5 blastocysts compared to Day-6 (p=0.03). CONCLUSIONS: The developmental potential of embryos should not be considered a negative influence on pregnancy outcomes, especially good grade blastocysts vitrified on Days 5 and 6. Fully expanded blastocysts on Day-5 are considered similar in terms of outcomes to delayed Day-6 blastocysts; however, live-birth rates are significantly higher in Day-5 blastocysts.

Basic and applied features in the cryopreservation progress of bovine embryos.

The expansion of the use of in vitro production techniques has revolutionized the bovine embryo market. In the last decade, we have seen the number of in vitro produced (IVP) embryos surpass the number of in vivo-derived (IVD) embryos obtained worldwide. Concomitantly, other biotechnologies were also improved, following the global trend. Embryo cryopreservation has received special attention, as it is one of the tools capable of disseminating in vitro production. Currently, two protocols are available: slow freezing and vitrification. Both have advantages and disadvantages regarding their application and, many aspects need to be considered before their use. In this review, we discuss in vitro production market trends, cellular and molecular features involved in embryo response to cryopreservation, and addressed cryo-storage period and embryonic developmental stage on cryosurvival. In addition, we also presented an overview of some aspects that impact the pregnancy rate following transfer of fresh and cryopreserved IVP embryos.

Prevention of Premature Ovulation by Administration of Gonadotropin Releasing Hormone Antagonist the day After Ovulation Triggering in Diminished Ovarian Reserve Patients / Prevenção da ovulação prematura por meio da administração de antagonismo de liberação de gonadotropismo no dia seguinte à ovulação

Abstract Objective The aim of the present retrospective study was to investigate the effectiveness of single-dose gonadotropin releasing hormone (GnRH) antagonist administration, the day after human chorionic gonadotropin (hCG) triggering for final oocyte maturation, on the prevention of premature luteinization in patients with diminished ovarian reserve in in-vitro fertilization (IVF) cycles. The secondary objective of the study was to search the effect of this protocol on pregnancy outcomes. Methods This is a retrospective study including 267 infertile patients who have single antral follicle seen with ultrasonography on the 2nd or 3rd day of the menstrual cycle before starting IVF treatment. We randomized patients into two groups. The case group comprised patients who had single-dose GnRH antagonist injection the day after hCG triggering formed, and the patients who had the standard treatment regime formed the control group. In both groups, the oocytes were collected 36 hours after hCG injection. Results The premature ovulation rate was significantly low in the case group compared with the control group (6.86 versus 20.6% per scheduled cycle) (p=0.022). Also, the oocyte retrieval rate (93.14 versus 67.87% per scheduled cycle) (p=0.013), the oocyte maturity rate (79.42 versus 47.87%) (p=0.041), the fertilization rate (65.68 versus 34.54%) (p=0.018), and the embryo transfer rate per scheduled cycle (44.11 versus 18.78%) (p=0.003) were higher in the GnRH antagonist group than in the control group. Conclusion The administration of GnRH antagonist the day after hCG trigger in IVF treatments of patients with diminished ovarian reserve enabled a significant decrease in the rate of premature ovulation but had no effect on live birth rate.

Resumo Objetivo O objetivo do presente estudo retrospectivo foi investigar a eficácia da administração do antagonista do hormônio liberador da gonadotrofina (GnRH) em dose única no dia seguinte ao desencadeamento da gonadotrofina coriônica humana (hCG) para a maturação final do oócito, na prevenção da luteinização prematura em pacientes com diminuição do ovário reserva em ciclos de fertilização in vitro (FIV). O objetivo secundário do estudo foi pesquisar o efeito deste protocolo nos resultados da gravidez. Métodos Trata-se de um estudo retrospectivo incluindo 267 pacientes inférteis que apresentam um único folículo antral visto por ultrassonografia no 2° ou 3° dia do ciclo menstrual antes de iniciar o tratamento de FIV. Nós randomizamos os pacientes em dois grupos. Os pacientes que receberam injeção de antagonista de GnRH em dose única no dia seguinte ao desencadeamento do hCG formaram o grupo caso, e os pacientes que receberam o regime de tratamento padrão formaram o grupo controle. Em ambos os grupos, os oócitos foram coletados 36 horas após a injeção de hCG. Resultados A taxa de ovulação prematura foi significativamente baixa no grupo caso em comparação com o grupo controle (6,86 versus 20,6% por ciclo programado) (p=0,022). Além disso, a taxa de recuperação de oócitos (93,14 versus 67,87% por ciclo programado) (p=0,013), a taxa de maturidade do oócito (79,42 versus 47,87%) (p=0,041), a taxa de fertilização (65,68 versus 34,54%) (p=0,018) e a taxa de transferência de embriões por ciclo programado (44,11 versus 18,78%) (p=0,003) foram maiores no grupo antagonista de GnRH do que no grupo controle. Conclusão A administração de antagonista de GnRH, no dia seguinte ao desencadeamento de hCG em tratamentos de FIV de pacientes com reserva ovariana diminuída permitiu uma redução significativa na taxa de ovulação precoce,mas não teve efeito na taxa de nascidos vivos.

Efficacy of a modified transvaginal ultrasound-guided fresh embryo transfer procedure.

OBJECTIVE: To present a modified transvaginal ultrasound (TVUS) guided embryo transfer (ET) procedure and analyze its efficacy in comparison with conventional transabdominal ultrasound (TAUS) guided ET in an unselected population of Brazilian women. METHODS: This retrospective observational case-control study involved 447 fresh ET cycles, 221 guided by TVUS (Group 1), conducted between June 2016 and February 2019, and 226 by TAUS (Group 2), conducted between July 2012 and December 2015. Pregnancy rate was the main endpoint. Groups were compared using the Z test at a level of significance of 95% (p≤0.05). RESULTS: Patient age ranged from 21 and 48 years; mean age was 37.7 years in Group 1 and 38 years in Group 2. Overall, patients that underwent TVUS-guided fresh ET demonstrated significantly higher pregnancy rates than their counterparts that underwent TAUS-guided fresh ET (p=0.0107). TVUS-guided fresh ET also yielded significantly higher pregnancy rates in the subgroups of women aged 36-39 years (p=0.0037) and ≥ 40 years (p=0.0025). However, no significant pregnancy rate difference was observed in women aged ≤ 35 years (p=0.0905). CONCLUSIONS: The results suggested that TVUS-guided fresh ET was at least as effective as TAUS-guided fresh ET in the studied sample. Pending further prospective studies to better ascertain the effect of TVUS-guided ET, the technique presented deserves consideration since it can offer better visualization, more comfort to patients, and requires only one operator, without negatively affecting pregnancy results.

Pre-sincronización con Progesterona para la Inducción de Ciclicidad en Vacas Bos taurus indicus en Periodo de Anestro Posparto / Presynchronization with Progesterone for Induction of Cyclicity in Bos Taurus Indicus Cows in Postpartum Anestrus Period / Pré-sincronização com Progesterona para a Indução de Ciclicidade em Vacas Bos Taurus Indicus em Período de Anestro Pós-Parto

Resumen Objetivo. Este trabajo tuvo como objetivo evaluar el efecto de la pre-sincronización con progesterona (P4) por 3 y 6 días en vacas de raza Nelore en periodo de anestro posparto, sometidas a un programa de inseminación artificial a tiempo fijo (IATF). Materiales y métodos: Fueron utilizadas 74 vacas multíparas de raza Nelore con estado de condición corporal de 2,5. Las vacas fueron sometidas a tres grupos experimentales, grupo control y grupos pre-sincronizados con P4 por un periodo de 3 y 6 días. Para la determinación del estado de anestro posparto, fueron realizadas ecografías y toma de muestras de sangre con la finalidad de verificar la ausencia de P4 endógena. Cuarenta y cinco días después de la IA fue realizado el diagnóstico de la gestación. Los datos fueron obtenidos por análisis descriptivo y en el caso de presentación de diferencias significativas fue utilizado la prueba de Chi-cuadrado, considerándose una frecuencia de P< 0,05. Resultados: Fue observada mayor tasa de gestación para el grupo que fue pre-sincronizado por tres días con P4 (40 %), con relación a los grupos de seis días de pre-sincronización y control (25 % y 32 %, respectivamente). Conclusión: Es posible concluir que la pre-sincronización con P4 por tres días, mejoró la tasa de gestación de vacas de raza Nelore en periodo de anestro posparto.

Abstract Objective: The objective of this study was to evaluate the effect of pre-synchronization with progesterone (P4) for 3 and 6 days in Nelore cows in postpartum anestrus period, submitted to a fixed-time artificial insemination program (FTAI). Materials and methods: Seventy-four multiparous Nelore cows with a body condition of 2.5 were used. The cows were submitted to three experimental groups, control group and groups pre-synchronized with P4 for a period of 3 and 6 days. For the determination of postpartum anestrus status, ultrasound scans and blood samples were taken to verify the absence of endogenous P4. Forty-five days after AI, gestation was diagnosed. Data were obtained by descriptive analysis and in the case of presentation of significant differences the Chi-square test was used, considering a frequency of P < 0.05. Results: A higher gestation rate was observed for the group that was pre-synchronized for three days with P4 (40 %), in relation to the groups of six days of pre-synchronization and control (25 % and 32 %, respectively). Conclusion: It is possible to conclude that the pre-synchronization with P4 for three days improved the gestation rate of Nelore cows in the postpartum anestrus period.

Resumo Objetivo: O objetivo deste estudo foi avaliar o efeito da pré-sincronização com progesterona (P4) durante 3 e 6 dias em vacas de raça Nelore em período de anestro pós-parto, submetidas a um programa de inseminação artificial em tempo fixo (IATF). Materiais e métodos: Foram utilizadas 74 vacas multíparas da raça Nelore com estado de condição corporal de 2,5. As vacas foram submetidas a três grupos experimentais, grupo controle e grupos pré-sincronizados com P4 por um período de 3 e 6 dias. Para a determinação do estado de anestro pós-parto, foram realizadas ultrassonografias e coleta de amostras de sangue com a finalidade de verificar a ausência de P4 endógena. Quarenta e cinco dias após a IA foi realizado o diagnostico da gestação. Os dados foram obtidos por análise descritiva e no caso de diferenças significativas foi utilizado o teste do Quí-quadrado, considerando-se uma freqüência de P < 0,05. Resultados: Foi observada maior taxa de gestação para o grupo que foi pré-sincronizado por três dias com P4 (40 %), com relação aos grupos de seis dias de pré-sincronização e controle (25 % e 32 %, respetivamente). Conclusão: É possível concluir que a pré-sincronização com P4 por três dias, melhorou a taxa de gestação de vacas Nelore em período de anestro pós-parto.

Postpartum uterine diseases negatively impact the time to pregnancy in grazing dairy cows from high-altitude tropical herds.

Infertility is a common consequence of cows suffering from postpartum uterine diseases. Diseases from a uterine origin in early lactation affect both uterine and ovarian tissues decreasing the probability of pregnancy. The objective of the present study was to determine the impact of clinical metritis, clinical endometritis, and subclinical endometritis on days open in cows from high-altitude tropical dairy herds. A single cohort longitudinal study was conducted from January 2018 to February 2019, which included 248 cows enrolled from five commercial high-altitude tropical dairy herds in the northern region of the Department of Antioquia, Colombia. A directed acyclic graph was used to identify minimal sufficient adjustment sets for each exposure variable of interest. Based on the directed acyclic graph, three models (one for each of clinical metritis, clinical endometritis, and subclinical endometritis) were proposed to assess the impact of postpartum uterine diseases on days open. The time at risk was defined as the days elapsed from calving until pregnancy (event or censure). Observations were right-censored if cows were either culled, dead, were lost to follow up, suffered a systemic illness that required the use of parenteral drugs, or if they were not pregnant at 210 postpartum days. Three Cox proportional hazards models were proposed to estimate the Hazard Ratios (HR) at any point in the follow-up period for each exposure variable. The hazard of pregnancy was significantly lower for cows with metritis (40 %; HR = 0.60; 95 % CI: 0.43 - 0.86), clinical endometritis (69 %; HR = 0.31; 95 % CI: 0.22 - 0.45), and subclinical endometritis (76 %; HR = 0.24; 95 % CI: 0.16 - 0.36) compared to their herd mates without these conditions. These results provide evidence of the negative impact of postpartum uterine diseases on time to pregnancy in grazing lactating dairy cows from high-altitude tropical herds.

Comparison of two commercial embryo culture media (SAGE-1 step single medium vs. G1-PLUSTM/G2-PLUSTM sequential media): Influence on in vitro fertilization outcomes and human embryo quality.

OBJECTIVE: To compare embryo quality, fertilization, implantation, miscarriage and clinical pregnancy rates for embryos cultured in two different commercial culture media until D-2 or D-3. METHODS: In this retrospective study, we analyzed 189 cycles performed in 2016. Metaphase II oocytes were microinjected and allocated into single medium (SAGE 1-STEP, Origio) until transferred, frozen or discarded; or, if sequential media were used, the oocytes were cultured in G1-PLUSTM (Vitrolife) up to D-2 or D-3 and in G2-PLUSTM (Vitrolife) to transfer. On the following day, the oocytes were checked for normal fertilization and on D-2 and D-3 for morphological classification. Statistical analysis was performed using the chi-square and Mann-Whitney tests in PASW Statistics 18.0. RESULTS: The fertilization rates were 70.07% for single and 69.11% for sequential media (p=0.736). The mean number of embryos with high morphological quality (class A/B) was higher in the single medium than in the sequential media: D-2 [class A (190 vs. 107, p<0.001), B (133 vs. 118, p=0.018)]; D-3 [class A (40 vs. 19, p=0.048) but without differences in class B (40 vs. 49)]. Consequently, a higher number of embryos cultured in single medium were frozen: 197 (21.00%) vs. sequential: 102 (11.00%), p<0.001. No differences were found in implantation rates (30.16% vs. 25.57%, p=0.520), clinical pregnancy rates (55.88% vs. 41.05%, p=0.213), or miscarriage rates (14.29% vs. 9.52%, p=0.472). CONCLUSION: Embryo culture in single medium yields greater efficiency per cycle than in sequential media. Higher embryo quality and quantity were achieved, resulting in more frozen embryos. There were no differences in clinical pregnancy rates.

Evolution of fixed-time AI in dairy cattle in Brazil.

Various programs have been used to synchronize ovulation of a fertile oocyte, accompanied by fixed-time artificial insemination (FTAI). These programs involve a series of hormonal treatments to achieve four physiologic outcomes: 1) synchronize an ovarian follicular wave; 2) optimize conditions for ovulatory follicle development; 3) synchronize corpus luteum (CL) regression; and 4) synchronize ovulation. This manuscript summarizes studies conducted in Brazil with lactating dairy cows that aimed to increase pregnancy rates to E2/P4-based programs.

Tasa acumulada de embarazo clínico y en curso en ciclos de inseminación intrauterina y análisis de los ciclos según la edad, conteo de folículos maduros y estimulación con antagonista de GnRH / Clinical and ongoing cumulative pregnancy rates in cycles of intrauterine insemination and analysis of the cycles according to age, follicular count and GnRH antagonist use

Resumen Objetivo: Determinar la tasa acumulada de embarazo clínico en ciclos de inseminación intrauterina en pacientes estimuladas con gonadotropinas según el número de folículos maduros desarrollados y edad, así como la influencia de los antagonistas de GnRH en su desarrollo y en la tasa de embarazo. Materiales y métodos: Estudio analítico, retrospectivo, en el que se evaluaron ciclos de inseminación intrauterina de pacientes con diferentes protocolos de gonadotropinas en un periodo de dos años. La muestra se dividió en grupos: menores de 35 y más o menos mayores de 35 años y uso o no de antagonista de GnRH. Resultados: Se evaluaron 229 ciclos de inseminación intrauterina en 172 pacientes; de éstas 64% eran menores de 34 años (grupo 1) y 36% mayores de 35 años. El 50% de las pacientes desarrolló de 2 a 3 folículos maduros y 10% de 4 a 6, con una tendencia en aumento de la tasa de embarazo con el desarrollo de hasta 4 folí culos maduros. El antagonista de GnRH no parece relacionarse con mejores tasas de embarazo clínico o en curso en ciclos con más de un folículo maduro. La tasa acumulada de embarazo clínico en tres ciclos fue de 40.6%, mientras que la tasa acumulada de embarazo en curso fue 26.1%. Conclusiones: Hubo relación proporcional entre el número de folículos maduros desarrollados y la tasa de embarazo clínico y en curso. La edad no parece haber tenido influencia en las tasas de em barazo y no pudo demostrarse la eficacia del antagonista en ciclos con desarrollo multifolicular.

Abstract Objective: To determine the cumulative clinical pregnancy rate in cycles of intrauterine insemination with gonadotropin stimulation in relation to number of mature follicles and age and the use of GnRH antagonist on its development. Materials and methods: Analytical, retrospective study in which intrauterine insemination cycles of patients with different gonadotropin protocols were evaluated over a period of two years. The patients were divided in two groups: <35 and ≥35 years old and the use of GnRH antagonist. Results: We evaluated 229 cycles of intrauterine insemination in 172 patients; Of these 64% were under 34 years old (group 1) and 36% over 35 years. The use of antGnRH did not appear to have relation with better clinical and ongoing pregnancy rates in cycles with more than one mature follicle. The cumulative pregnancy rate in three cycles was 40.6%, and cumulative ongoing pregnancy rates was 26.1%. Conclusions: The more mature follicle developed the higher clinical and ongoing pregnancy rates. The age did not appear to have influence in the pregnancy rates, there is no better pregnancy rates with use of antGnRH in cycles with multifolicular developed.

Evolution of fixed-time AI in dairy cattle in Brazil

Various programs have been used to synchronize ovulation of a fertile oocyte, accompanied by fixed-time artificial insemination (FTAI). These programs involve a series of hormonal treatments to achieve four physiologic outcomes: 1) synchronize an ovarian follicular wave; 2) optimize conditions for ovulatory follicle development; 3) synchronize corpus luteum (CL) regression; and 4) synchronize ovulation. This manuscript summarizes studies conducted in Brazil with lactating dairy cows that aimed to increase pregnancy rates to E2/P4-based programs.

Evolution of fixed-time AI in dairy cattle in Brazil

Various programs have been used to synchronize ovulation of a fertile oocyte, accompanied by fixed-time artificial insemination (FTAI). These programs involve a series of hormonal treatments to achieve four physiologic outcomes: 1) synchronize an ovarian follicular wave; 2) optimize conditions for ovulatory follicle development; 3) synchronize corpus luteum (CL) regression; and 4) synchronize ovulation. This manuscript summarizes studies conducted in Brazil with lactating dairy cows that aimed to increase pregnancy rates to E2/P4-based programs.(AU)

Egg donation of vitrified oocytes bank produces similar pregnancy rates by blastocyst transfer when compared to fresh cycle.

PURPOSE: Advances in reproductive techniques, mainly the introduction of oocyte vitrification, have provided the opportunity to conceive from oocyte banks. The aim of this study was to compare the clinical outcomes of fresh and vitrified oocytes in an egg donation program following blastocyst transfer. METHODS: This retrospective observational study included 504 oocyte donation cycles. All donor women were younger than 30 years of age. The recipient cycles were divided into two groups: fresh oocytes (n = 78) or vitrified oocytes (n = 426). All oocytes were fertilized by ICSI using ejaculated sperm, followed by blastocyst transfer. Endometrium preparation was performed with estradiol valerate plus micronized progesterone according to standard protocols. RESULTS: Recipients were of similar age (fresh 42.0 ± 4.5 years vs vitrified 41.8 ± 4.8 years; p = 0.790). The fresh group received more mature oocytes for injection compared to the vitrified group (10.1 ± 2.8 vs 9.2 ± 2.2; p = 0.005). The two pronuclei (2PN) rate (74.5 vs 77.4%; p = 0.195) and blastocyst rate (48.8 vs 51.6%; 0.329) were similar between the fresh and vitrified groups, respectively. The rates of clinical pregnancy were 60.9% in the fresh and 59.0% in the vitrified groups (p = 0.771). CONCLUSIONS: Our findings suggest that vitrified oocytes result in similar pregnancy rates when compared to fresh oocytes with blastocyst transfer in an egg donation program. Moreover, vitrified oocytes may allow for a better cycle schedule, starting with a lower number of oocytes to be fertilized. Therefore, we hypothesize that egg banks with vitrified oocytes could be safely utilized in an egg donation program.

Influencia da concentração espermática sobre a Taxa de Fertilidade em Ovelhas Inseminadas com Sêmen congelado / Influences of sperm concentration on Fertility Rate in Sheep inseminated with frozen semen

The experiment compared the pregnancy rates in sheep submitted to IA, to evaluate the influence ofsperm concentration on fertility rate in sheep inseminated with frozen semen. In experiment run 37 females wereused, subject to synchronization of estrus and divided into two groups: G1 (n = 19), using artificial inseminationwith a concentration of 200 million viable spermatozoa and G2 (n = 18), using artificial insemination is at aconcentration of 100 million sperm. Pregnancy rates were 66.66% and 77.77% in sheep that were inseminatedwith the concentration 200 and 100 million sperm respectively transcervical and the sheep that have beeninseminated by laparoscopy at the same concentrations as pregnancy rates were 50% and 77.77% respectively.The concentrations used have shown - is quite effective when compared pregnancy rates in each group. Butneeds more in vivo studies.

Influencia da concentração espermática sobre a Taxa de Fertilidade em Ovelhas Inseminadas com Sêmen congelado / Influences of sperm concentration on Fertility Rate in Sheep inseminated with frozen semen

The experiment compared the pregnancy rates in sheep submitted to IA, to evaluate the influence ofsperm concentration on fertility rate in sheep inseminated with frozen semen. In experiment run 37 females wereused, subject to synchronization of estrus and divided into two groups: G1 (n = 19), using artificial inseminationwith a concentration of 200 million viable spermatozoa and G2 (n = 18), using artificial insemination is at aconcentration of 100 million sperm. Pregnancy rates were 66.66% and 77.77% in sheep that were inseminatedwith the concentration 200 and 100 million sperm respectively transcervical and the sheep that have beeninseminated by laparoscopy at the same concentrations as pregnancy rates were 50% and 77.77% respectively.The concentrations used have shown - is quite effective when compared pregnancy rates in each group. Butneeds more in vivo studies.(AU)