Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium.
Centre for Evidence-Based Practice, Belgian Red Cross, Mechelen, Belgium.
Cochrane Database Syst Rev. 2021 Apr 29;4(4):CD008189. doi: 10.1002/14651858.CD008189.pub3.
Infertility is a prevalent problem that has significant consequences for individuals, families, and the community. Modifiable lifestyle factors may affect the chance of people with infertility having a baby. However, no guideline is available about what preconception advice should be offered. It is important to determine what preconception advice should be given to people with infertility and to evaluate whether this advice helps them make positive behavioural changes to improve their lifestyle and their chances of conceiving.
To assess the safety and effectiveness of preconception lifestyle advice on fertility outcomes and lifestyle behavioural changes for people with infertility.
We searched the Cochrane Gynaecology and Fertility Group Specialised Register of controlled trials, CENTRAL, MEDLINE, Embase, PsycINFO, AMED, CINAHL, trial registers, Google Scholar, and Epistemonikos in January 2021; we checked references and contacted field experts to identify additional studies.
We included randomised controlled trials (RCTs), randomised cross-over studies, and cluster-randomised studies that compared at least one form of preconception lifestyle advice with routine care or attention control for people with infertility.
We used standard methodological procedures recommended by Cochrane. Primary effectiveness outcomes were live birth and ongoing pregnancy. Primary safety outcomes were adverse events and miscarriage. Secondary outcomes included reported behavioural changes in lifestyle, birth weight, gestational age, clinical pregnancy, time to pregnancy, quality of life, and male factor infertility outcomes. We assessed the overall quality of evidence using GRADE criteria.
We included in the review seven RCTs involving 2130 participants. Only one RCT included male partners. Three studies compared preconception lifestyle advice on a combination of topics with routine care or attention control. Four studies compared preconception lifestyle advice on one topic (weight, alcohol intake, or smoking) with routine care for women with infertility and specific lifestyle characteristics. The evidence was of low to very low-quality. The main limitations of the included studies were serious risk of bias due to lack of blinding, serious imprecision, and poor reporting of outcome measures. Preconception lifestyle advice on a combination of topics versus routine care or attention control Preconception lifestyle advice on a combination of topics may result in little to no difference in the number of live births (risk ratio (RR) 0.93, 95% confidence interval (CI) 0.79 to 1.10; 1 RCT, 626 participants), but the quality of evidence was low. No studies reported on adverse events or miscarriage. Due to very low-quality evidence, we are uncertain whether preconception lifestyle advice on a combination of topics affects lifestyle behavioural changes: body mass index (BMI) (mean difference (MD) -1.06 kg/m², 95% CI -2.33 to 0.21; 1 RCT, 180 participants), vegetable intake (MD 12.50 grams/d, 95% CI -8.43 to 33.43; 1 RCT, 264 participants), alcohol abstinence in men (RR 1.08, 95% CI 0.74 to 1.58; 1 RCT, 210 participants), or smoking cessation in men (RR 1.01, 95% CI 0.91 to 1.12; 1 RCT, 212 participants). Preconception lifestyle advice on a combination of topics may result in little to no difference in the number of women with adequate folic acid supplement use (RR 0.98, 95% CI 0.95 to 1.01; 2 RCTs, 850 participants; I² = 4%), alcohol abstinence (RR 1.07, 95% CI 0.99 to 1.17; 1 RCT, 607 participants), and smoking cessation (RR 1.01, 95% CI 0.98 to 1.04; 1 RCT, 606 participants), on low quality evidence. No studies reported on other behavioural changes. Preconception lifestyle advice on weight versus routine care Studies on preconception lifestyle advice on weight were identified only in women with infertility and obesity. Compared to routine care, we are uncertain whether preconception lifestyle advice on weight affects the number of live births (RR 0.94, 95% CI 0.62 to 1.43; 2 RCTs, 707 participants; I² = 68%; very low-quality evidence), adverse events including gestational diabetes (RR 0.78, 95% CI 0.48 to 1.26; 1 RCT, 317 participants; very low-quality evidence), hypertension (RR 1.07, 95% CI 0.66 to 1.75; 1 RCT, 317 participants; very low-quality evidence), or miscarriage (RR 1.50, 95% CI 0.95 to 2.37; 1 RCT, 577 participants; very low-quality evidence). Regarding lifestyle behavioural changes for women with infertility and obesity, preconception lifestyle advice on weight may slightly reduce BMI (MD -1.30 kg/m², 95% CI -1.58 to -1.02; 1 RCT, 574 participants; low-quality evidence). Due to very low-quality evidence, we are uncertain whether preconception lifestyle advice affects the percentage of weight loss, vegetable and fruit intake, alcohol abstinence, or physical activity. No studies reported on other behavioural changes. Preconception lifestyle advice on alcohol intake versus routine care Studies on preconception lifestyle advice on alcohol intake were identified only in at-risk drinking women with infertility. We are uncertain whether preconception lifestyle advice on alcohol intake affects the number of live births (RR 1.15, 95% CI 0.53 to 2.50; 1 RCT, 37 participants; very low-quality evidence) or miscarriages (RR 1.31, 95% CI 0.21 to 8.34; 1 RCT, 37 participants; very low-quality evidence). One study reported on behavioural changes for alcohol consumption but not as defined in the review methods. No studies reported on adverse events or other behavioural changes. Preconception lifestyle advice on smoking versus routine care Studies on preconception lifestyle advice on smoking were identified only in smoking women with infertility. No studies reported on live birth, ongoing pregnancy, adverse events, or miscarriage. One study reported on behavioural changes for smoking but not as defined in the review methods.
AUTHORS' CONCLUSIONS: Low-quality evidence suggests that preconception lifestyle advice on a combination of topics may result in little to no difference in the number of live births. Evidence was insufficient to allow conclusions on the effects of preconception lifestyle advice on adverse events and miscarriage and on safety, as no studies were found that looked at these outcomes, or the studies were of very low quality. This review does not provide clear guidance for clinical practice in this area. However, it does highlight the need for high-quality RCTs to investigate preconception lifestyle advice on a combination of topics and to assess relevant effectiveness and safety outcomes in men and women with infertility.
不孕是一种普遍存在的问题，会对个人、家庭和社区产生重大影响。可改变的生活方式因素可能会影响不孕患者生育的机会。然而，目前尚无关于应提供何种孕前建议的指南。重要的是要确定应向不孕患者提供何种孕前建议，并评估这些建议是否有助于他们做出积极的行为改变，以改善他们的生活方式和受孕机会。
评估针对不孕患者的生育结局和生活方式行为改变的孕前生活方式建议的安全性和有效性。
我们检索了 Cochrane 妇科和生育学组的对照试验专库、CENTRAL、MEDLINE、Embase、PsycINFO、AMED、CINAHL、试验注册处、Google Scholar 和 Epistemonikos，检索时间为 2021 年 1 月；我们还检查了参考文献并联系了领域专家，以确定其他研究。
我们纳入了比较至少一种形式的孕前生活方式建议与常规护理或对照护理的随机对照试验（RCT）、随机交叉研究和整群随机研究，这些研究对象为不孕患者。
我们使用了 Cochrane 推荐的标准方法学程序。主要有效性结局是活产和持续妊娠。主要安全性结局是不良事件和流产。次要结局包括报告的生活方式改变、出生体重、妊娠周数、临床妊娠、受孕时间、生活质量和男性因素不孕结局。我们使用 GRADE 标准评估了整体证据质量。
我们纳入了 7 项 RCT，涉及 2130 名参与者。只有一项 RCT 纳入了男性伴侣。三项研究比较了针对多种话题的孕前生活方式建议与常规护理或对照护理。四项研究比较了针对体重、饮酒或吸烟等特定生活方式特征的不孕妇女的单一话题的孕前生活方式建议与常规护理。证据质量为低至极低。纳入研究的主要局限性是由于缺乏盲法导致严重的偏倚风险、严重的不精确性以及对结局测量的报告不佳。针对多种话题的孕前生活方式建议与常规护理或对照护理相比，针对多种话题的孕前生活方式建议可能对活产率没有影响（风险比（RR）0.93，95%置信区间（CI）0.79 至 1.10；1 项 RCT，626 名参与者），但证据质量低。没有研究报告不良事件或流产。由于极低质量的证据，我们不确定针对多种话题的孕前生活方式建议是否会影响生活方式行为改变：体重指数（BMI）（平均差（MD）-1.06kg/m²，95%CI-2.33 至 0.21；1 项 RCT，180 名参与者）、蔬菜摄入量（MD 12.50 克/天，95%CI-8.43 至 33.43；1 项 RCT，264 名参与者）、男性戒酒（RR 1.08，95%CI 0.74 至 1.58；1 项 RCT，210 名参与者）或男性戒烟（RR 1.01，95%CI 0.91 至 1.12；1 项 RCT，212 名参与者）。针对多种话题的孕前生活方式建议可能对适当叶酸补充剂使用的女性数量没有影响（RR 0.98，95%CI 0.95 至 1.01；2 项 RCT，850 名参与者；I²=4%）、戒酒（RR 1.07，95%CI 0.99 至 1.17；1 项 RCT，607 名参与者）和戒烟（RR 1.01，95%CI 0.98 至 1.04；1 项 RCT，606 名参与者），但证据质量低。没有研究报告其他行为改变。针对体重的孕前生活方式建议与常规护理相比，仅在不孕且肥胖的女性中发现了针对体重的孕前生活方式建议研究。与常规护理相比，我们不确定针对体重的孕前生活方式建议是否会影响活产率（RR 0.94，95%CI 0.62 至 1.43；2 项 RCT，707 名参与者；I²=68%；极低质量证据）、不良事件包括妊娠期糖尿病（RR 0.78，95%CI 0.48 至 1.26；1 项 RCT，317 名参与者；极低质量证据）、高血压（RR 1.07，95%CI 0.66 至 1.75；1 项 RCT，317 名参与者；极低质量证据）或流产（RR 1.50，95%CI 0.95 至 2.37；1 项 RCT，577 名参与者；极低质量证据）。对于不孕且肥胖的女性，针对体重的孕前生活方式建议可能会稍微降低 BMI（MD-1.30kg/m²，95%CI-1.58 至-1.02；1 项 RCT，574 名参与者；低质量证据）。由于极低质量的证据，我们不确定针对体重的孕前生活方式建议是否会影响体重减轻的百分比、蔬菜和水果摄入量、戒酒或体育锻炼。没有研究报告其他行为改变。针对饮酒的孕前生活方式建议与常规护理相比，仅在有风险饮酒的不孕女性中发现了针对饮酒的孕前生活方式建议研究。我们不确定针对饮酒的孕前生活方式建议是否会影响活产率（RR 1.15，95%CI 0.53 至 2.50；1 项 RCT，37 名参与者；极低质量证据）或流产（RR 1.31，95%CI 0.21 至 8.34；1 项 RCT，37 名参与者；极低质量证据）。一项研究报告了与饮酒有关的行为变化，但与本综述方法中定义的不同。没有研究报告不良事件或其他行为改变。针对吸烟的孕前生活方式建议与常规护理相比，仅在吸烟的不孕女性中发现了针对吸烟的孕前生活方式建议研究。没有研究报告活产、持续妊娠、不良事件或流产。一项研究报告了与吸烟有关的行为变化，但与本综述方法中定义的不同。
低质量证据表明，针对多种话题的孕前生活方式建议可能对活产率没有影响。由于没有研究关注这些结局，或研究质量非常低，因此无法就孕前生活方式建议的效果和安全性得出明确的结论，包括不良事件和流产，以及安全性，这需要高质量的 RCT 来调查针对多种话题和男性以及不孕患者的孕前生活方式建议，并评估相关的有效性和安全性结局。这篇综述并没有为这一领域的临床实践提供明确的指导。然而，它确实强调了需要高质量的 RCT 来调查针对多种话题的孕前生活方式建议，并评估相关的有效性和安全性结局，包括男性和不孕患者。
