Purpose

Obesity, measured by body mass index (BMI), is implicated in adverse pregnancy outcomes for women seeking in vitro fertilization (IVF) care. However, the shape of the dose-response relationship between BMI and IVF outcomes remains unclear.

Methods

We therefore conducted a dose-response meta-analysis using a random effects model to estimate summary relative risk (RR) for clinical pregnancy (CPR), live birth (LBR), and miscarriage risk (MR) after IVF.

Results

A total of 18 cohort-based studies involving 975,889 cycles were included. For each 5-unit increase in BMI, the summary RR was 0.95 (95% CI: 0.94–0.97) for CPR, 0.93 (95% CI: 0.92-0.95) for LBR, and 1.09 (95% CI: 1.05-1.12) for MR. There was evidence of a non-linear association between BMI and CPR (P_{non-linearity} < 10⁻⁵) with CPR decreasing sharply among obese women (BMI > 30). Non-linear dose-response meta-analysis showed a relatively flat curve over a broad range of BMI from 16 to 30 for LBR (P_{non-linearity} = 0.0009). In addition, we observed a J-shaped association between BMI and MR (P_{non-linearity} = 0.006) with the lowest miscarriage risk observed with a BMI of 22–25.

Conclusions

In conclusion, obesity contributed to increased risk of adverse IVF outcomes in a non-linear dose-response manner. More prospective trials in evaluating the effect of body weight control are necessary.

中文翻译：

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女性体重指数与体外受精结果的非线性剂量反应关系

 目的

以体重指数 (BMI) 衡量的肥胖与寻求体外受精 (IVF) 护理的女性的不良妊娠结局有关。然而，BMI 和 IVF 结局之间的剂量反应关系的形状仍不清楚。

 方法

因此，我们使用随机效应模型进行了剂量反应荟萃分析，以估计 IVF 后临床妊娠 (CPR)、活产 (LBR) 和流产风险 (MR) 的总体相对风险 (RR)。

 结果

总共纳入了 18 项队列研究，涉及 975,889 个周期。对于 BMI 每增加 5 个单位，CPR 的总结 RR 为 0.95（95% CI：0.94-0.97），LBR 的总结 RR 为 0.93（95% CI：0.92-0.95），LBR 的总结 RR 为 1.09（95% CI：1.05-1.12）对于先生。有证据表明，BMI 和 CPR 之间存在非线性关联（P_非线性< 10 ^-5 ），肥胖女性的 CPR 急剧下降（BMI > 30）。非线性剂量反应荟萃分析显示，LBR 在 BMI 16 至 30 的广泛范围内具有相对平坦的曲线（P_非线性= 0.0009）。此外，我们观察到 BMI 和 MR 之间存在 J 形关联（P_非线性= 0.006），BMI 为 22-25 时流产风险最低。

 结论

总之，肥胖以非线性剂量反应方式导致 IVF 不良结果的风险增加。有必要进行更多前瞻性试验来评估体重控制的效果。