P-694 Is Body Mass index (BMI)<18.5 kg/m² the Best Cut-Off for IVF Success? Reevaluating the lower BMI Threshold
Notice bibliographique
Résumé
Abstract Study question What is the optimal BMI threshold for predicting lower live birth rates in IVF—18.5 kg/m² or a different cutoff? Summary answer Low-normal BMI(18.5-20.0kg/m²) is associated with significantly lower live births when compared to a BMI(20.0–25.0 kg/m²), suggesting how to define BMI thresholds for reproductive health. What is known already A U-shaped relationship between BMI and IVF outcomes has been described, with the negative effects of obesity extensively studied, while the impact of being underweight remains less explored. Furthermore, variability in IVF outcomes within the “normal” BMI range has not been well defined. The WHO established BMI categories based on epidemiological data linking BMI to general health outcomes. However, the lower threshold for normal weight (18.5 kg/m²) was primarily determined in the context of malnutrition, famine and low-resource settings. Therefore, applying WHO BMI thresholds to IVF populations may not fully capture the nuances relevant to reproductive health. Study design, size, duration Tri-continent retrospective cohort study of first-time IVF and ICSI cycles across three centers - ANDROFERT (Campinas, Brazil), Anatolia IVF (Ankara, Turkey), and IVFMD at My Duc Hospital (Ho Chi Minh City, Vietnam) between 2015 and 2017. Participants/materials, setting, methods Our study included 11,601 patients, of whom 10,443 had a normal BMI (18.5–25.0 kg/m²) according to WHO guidelines. Within this group, 2,406 patients had a low-normal BMI (18.5–19.99 kg/m²), while 8,037 had a BMI of 20.0–25.0 kg/m², referred to as “true-normal.” Additionally, 1,158 patients were classified as underweight, with a BMI below 18.5 kg/m². Main results and the role of chance Patients with a low-normal BMI were younger than those in the 20–25 kg/m² group and had higher AFC and AMH levels, as well as different sperm parameters (P < 0.001 for all). However, there were no significant differences in infertility duration, number of oocytes retrieved, fertilization rates, or the number of transferable embryos.Patients with a low-normal BMI had significantly lower live birth rates following a fresh embryo transfer than those with a BMI of 20.0–25.0 kg/m² (16.2%vs.20.1%,p<0.001). This difference remained significant after adjusting for confounding variables, including age, AFC, total gonadotropin dose, sperm count, and sperm motility (aOR:0.72-95%CI:0.62–0.82,p<0.001). Moreover, their cumulative delivery rate per aspiration was lower than that of the 20.0–25.0 kg/m² group (30.1%vs.31.7%; aOR:0.86-95%CI:0.77–0.97,p=0.01). The live birth rate (aOR:0.93-95%CI:0.75–1.15, p = 0.49) and cumulative delivery rate per aspiration (aOR:1.02-95%CI:0.86–1.20,p=0.86) did not differ between low-normal BMI patients and underweight patients. When comparing patients with a BMI of 20-25 kg/m² to all patients with a BMI under 20 kg/m², live birth rates were higher in the former (20.1%vs.16.9%, p < 0.01), and this difference remained significant after adjustment (aOR:0.80-95%CI:0.70–0.92,p=0.001). Similarly, the cumulative delivery rate per aspiration was higher in the 20-25 kg/m² group (31.7%vs.30.7%), with the difference remaining significant after adjustment (aOR:0.85-95%CI:0.77-0.94, p = 0.002). Limitations, reasons for caution Information on patients' overall health status and comorbidities, which may influence IVF outcomes, was unavailable. The lack of complete data on miscarriage rates is a limitation. Wider implications of the findings The threshold for adverse IVF outcomes appears to be BMI <20.0 kg/m² rather than the WHO-defined normal lower limit (18.5 kg/m²), as live birth and cumulative delivery rates decline in this range. This highlights the need for reproductive health-specific BMI categories which could enhance patient counseling and potentially enhance success. Trial registration number No
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,005 | 0,016 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,001 |
| Bibliométrie | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,001 | 0,001 |
| Science ouverte | 0,001 | 0,001 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,006 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».