Christensen Mette Wulf, Ingerslev Hans Jakob, Degn Birte, Kesmodel Ulrik Schiøler
Aarhus University Hospital, Aarhus, Denmark.
Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
PLoS One. 2016 Sep 21;11(9):e0163393. doi: 10.1371/journal.pone.0163393. eCollection 2016.
Overweight and obese women may require higher doses of gonadotrophin when undergoing In Vitro Fertilization Treatment (IVF). Consequently, one may expect a sub-optimal oocyte retrieval in the first treatment cycle and thus a larger compensation in gonadotrophin-dose in the following treatment-cycles and a more favorable outcome. The main objective was to explore if treatment cycle number modifies the outcome when investigating the effect of female Body Mass Index (BMI) on oocyte quantity in IVF.
A historical cohort study was conducted on 5,342 treatment-cycles during the period 1999-2009. Exclusion criteria were missing information on BMI or treatment type. Further, women were excluded if they had ovulated before oocyte retrieval. According to baseline BMI, women were divided into four categories following the World Health Organization standards. Multiple linear regressions analyses were performed accounting for the non-independence of ≥2 cycles in a woman.
Stratification according to cycle number revealed a more suboptimal outcome in the first treatment- cycles than in the following cycles, suggesting a possible interaction or effect modification from cycle number or a factor related to cycle number. The median dose of total follicular stimulating hormone given to the four BMI groups could not straight forwardly explain the less optimal oocyte outcome observed in first treatment cycles. No statistically significant differences were observed in oocyte yield for underweight, overweight and obesity compared to normal weight women when analyzing all treatment-cycles. Overweight women had significantly fewer mature (MII) oocytes (p = 0.009) than normal weight women, whereas no differences was observed for underweight and obese women.
Our study suggests a possible interaction or effect modification related to treatment cycle number. Investigating the effects of BMI on IVF-results in first treatment-cycles alone should be carried out cautiously.
超重和肥胖女性在接受体外受精治疗（IVF）时可能需要更高剂量的促性腺激素。因此，人们可能预期在第一个治疗周期中卵母细胞采集效果欠佳，进而在后续治疗周期中需要更大剂量的促性腺激素补偿，以获得更理想的结果。主要目的是探讨在研究女性体重指数（BMI）对IVF中卵母细胞数量的影响时，治疗周期数是否会改变结果。
对1999年至2009年期间的5342个治疗周期进行了一项历史性队列研究。排除标准为BMI或治疗类型信息缺失。此外，如果女性在卵母细胞采集前已排卵，则将其排除。根据基线BMI，按照世界卫生组织标准将女性分为四类。考虑到女性≥2个周期的非独立性，进行了多元线性回归分析。
根据周期数分层显示，第一个治疗周期的结果比后续周期更不理想，这表明周期数或与周期数相关的因素可能存在相互作用或效应修正。给予四个BMI组的总卵泡刺激素的中位剂量不能直接解释在第一个治疗周期中观察到的不太理想的卵母细胞结果。在分析所有治疗周期时，与正常体重女性相比，体重过轻、超重和肥胖女性的卵母细胞产量没有统计学上的显著差异。超重女性的成熟（MII）卵母细胞明显少于正常体重女性（p = 0.009），而体重过轻和肥胖女性则没有差异。
我们的研究表明，可能存在与治疗周期数相关的相互作用或效应修正。仅在第一个治疗周期中研究BMI对IVF结果的影响时应谨慎进行。
