How effective are weight-loss interventions for improving fertility in women and men who are overweight or obese?

A systematic review and meta-analysis of the evidence

Research output: Contribution to journalArticle

24 Citations (Scopus)
5 Downloads (Pure)

Abstract

BACKGROUND: The prevalence of obesity is increasing worldwide, with a corresponding increase in overweight and obese patients referred with infertility. This systematic review aimed to determine whether non-surgical weight reduction strategies result in an improvement in reproductive parameters affected by obesity, e.g. delayed time to pregnancy, oligozoospermia and azoospermia. No prior reviews have examined this within the general fertility population, or in both sexes.

OBJECTIVE AND RATIONALE: Our objective was to answer the question: 'In overweight and obese women, men and couples seeking fertility treatment, what non-surgical weight-loss interventions have been used, and how effective are they at weight loss and improving reproductive outcomes?'

SEARCH METHODS: An electronic search of MEDLINE, EMBASE and the Cochrane Library was performed for studies between January 1966 and March 2016. Text word and MESH search terms used related to infertility, weight and barriers to weight loss. Inclusion criteria were an intervention to change lifestyle evaluated in any study design in participants of either gender with an unfulfilled desire to conceive. Studies were excluded if they included participants not attempting pregnancy, with illnesses that might cause weight fluctuations, or studies evaluating bariatric surgery. Two reviewers performed data extraction and quality assessment using the Cochrane Risk of Bias Tool for randomized trials, and a ratified checklist (ReBIP) for non-randomized studies.

OUTCOMES: A total of 40 studies were included, of which 14 were randomised control trials. Primary outcomes were pregnancy, live birth rate and weight change. In women, reduced calorie diets and exercise interventions were more likely than control interventions to result in pregnancy [risk ratio 1.59, 95% CI (1.01, 2.50)], and interventions resulted in weight loss and ovulation improvement, where reported. Miscarriage rates were not reduced by any intervention.

WIDER IMPLICATIONS: Overweight and obese persons seeking fertility should be educated on the detrimental effects of fatness and the benefits of weight reduction, including improvement in pregnancy rates. A combination of a reduced calorie diet, by reducing fat and refined carbohydrate intake, and increased aerobic exercise should form the basis of programmes designed for such individuals. A lack of randomized studies in men and couples, and studies evaluating barriers to undertaking weight loss in infertile populations is evident, and future research should examine these issues further.

Original languageEnglish
Pages (from-to)681-705
Number of pages25
JournalHuman Reproduction Update
Volume23
Issue number6
Early online date13 Sep 2017
DOIs
Publication statusPublished - 1 Nov 2017

Fingerprint

Fertility
Meta-Analysis
Weight Loss
Infertility
Obesity
Time-to-Pregnancy
Exercise
Reducing Diet
Oligospermia
Weights and Measures
Pregnancy
Azoospermia
Bariatric Surgery
Live Birth
Spontaneous Abortion
Pregnancy Rate
Pregnancy Outcome
Ovulation
Checklist
Birth Weight

Keywords

  • Journal Article
  • infertility
  • obesity
  • weight loss
  • systematic review
  • diet
  • exercise

Cite this

@article{12351b08e30642869e25efe7f445ea0d,
title = "How effective are weight-loss interventions for improving fertility in women and men who are overweight or obese?: A systematic review and meta-analysis of the evidence",
abstract = "BACKGROUND: The prevalence of obesity is increasing worldwide, with a corresponding increase in overweight and obese patients referred with infertility. This systematic review aimed to determine whether non-surgical weight reduction strategies result in an improvement in reproductive parameters affected by obesity, e.g. delayed time to pregnancy, oligozoospermia and azoospermia. No prior reviews have examined this within the general fertility population, or in both sexes.OBJECTIVE AND RATIONALE: Our objective was to answer the question: 'In overweight and obese women, men and couples seeking fertility treatment, what non-surgical weight-loss interventions have been used, and how effective are they at weight loss and improving reproductive outcomes?'SEARCH METHODS: An electronic search of MEDLINE, EMBASE and the Cochrane Library was performed for studies between January 1966 and March 2016. Text word and MESH search terms used related to infertility, weight and barriers to weight loss. Inclusion criteria were an intervention to change lifestyle evaluated in any study design in participants of either gender with an unfulfilled desire to conceive. Studies were excluded if they included participants not attempting pregnancy, with illnesses that might cause weight fluctuations, or studies evaluating bariatric surgery. Two reviewers performed data extraction and quality assessment using the Cochrane Risk of Bias Tool for randomized trials, and a ratified checklist (ReBIP) for non-randomized studies.OUTCOMES: A total of 40 studies were included, of which 14 were randomised control trials. Primary outcomes were pregnancy, live birth rate and weight change. In women, reduced calorie diets and exercise interventions were more likely than control interventions to result in pregnancy [risk ratio 1.59, 95{\%} CI (1.01, 2.50)], and interventions resulted in weight loss and ovulation improvement, where reported. Miscarriage rates were not reduced by any intervention.WIDER IMPLICATIONS: Overweight and obese persons seeking fertility should be educated on the detrimental effects of fatness and the benefits of weight reduction, including improvement in pregnancy rates. A combination of a reduced calorie diet, by reducing fat and refined carbohydrate intake, and increased aerobic exercise should form the basis of programmes designed for such individuals. A lack of randomized studies in men and couples, and studies evaluating barriers to undertaking weight loss in infertile populations is evident, and future research should examine these issues further.",
keywords = "Journal Article, infertility, obesity, weight loss, systematic review, diet, exercise",
author = "Damian Best and Alison Avenell and Siladitya Bhattacharya",
note = "Acknowledgements Mrs Cynthia Fraser provided useful assistance in the formulation of a search strategy. Authors responding to queries included Gabrielle Turner-McGrievy, Ann Van Oers, Kamilla Karlsen, Kyra Sim, Amany Salama, Rebecca Thomson, Cherrie Galletly and Hanno Pijl. Funding No specific funding was sought. All authors were employed by the University of Aberdeen in a research capacity.",
year = "2017",
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T1 - How effective are weight-loss interventions for improving fertility in women and men who are overweight or obese?

T2 - A systematic review and meta-analysis of the evidence

AU - Best, Damian

AU - Avenell, Alison

AU - Bhattacharya, Siladitya

N1 - Acknowledgements Mrs Cynthia Fraser provided useful assistance in the formulation of a search strategy. Authors responding to queries included Gabrielle Turner-McGrievy, Ann Van Oers, Kamilla Karlsen, Kyra Sim, Amany Salama, Rebecca Thomson, Cherrie Galletly and Hanno Pijl. Funding No specific funding was sought. All authors were employed by the University of Aberdeen in a research capacity.

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N2 - BACKGROUND: The prevalence of obesity is increasing worldwide, with a corresponding increase in overweight and obese patients referred with infertility. This systematic review aimed to determine whether non-surgical weight reduction strategies result in an improvement in reproductive parameters affected by obesity, e.g. delayed time to pregnancy, oligozoospermia and azoospermia. No prior reviews have examined this within the general fertility population, or in both sexes.OBJECTIVE AND RATIONALE: Our objective was to answer the question: 'In overweight and obese women, men and couples seeking fertility treatment, what non-surgical weight-loss interventions have been used, and how effective are they at weight loss and improving reproductive outcomes?'SEARCH METHODS: An electronic search of MEDLINE, EMBASE and the Cochrane Library was performed for studies between January 1966 and March 2016. Text word and MESH search terms used related to infertility, weight and barriers to weight loss. Inclusion criteria were an intervention to change lifestyle evaluated in any study design in participants of either gender with an unfulfilled desire to conceive. Studies were excluded if they included participants not attempting pregnancy, with illnesses that might cause weight fluctuations, or studies evaluating bariatric surgery. Two reviewers performed data extraction and quality assessment using the Cochrane Risk of Bias Tool for randomized trials, and a ratified checklist (ReBIP) for non-randomized studies.OUTCOMES: A total of 40 studies were included, of which 14 were randomised control trials. Primary outcomes were pregnancy, live birth rate and weight change. In women, reduced calorie diets and exercise interventions were more likely than control interventions to result in pregnancy [risk ratio 1.59, 95% CI (1.01, 2.50)], and interventions resulted in weight loss and ovulation improvement, where reported. Miscarriage rates were not reduced by any intervention.WIDER IMPLICATIONS: Overweight and obese persons seeking fertility should be educated on the detrimental effects of fatness and the benefits of weight reduction, including improvement in pregnancy rates. A combination of a reduced calorie diet, by reducing fat and refined carbohydrate intake, and increased aerobic exercise should form the basis of programmes designed for such individuals. A lack of randomized studies in men and couples, and studies evaluating barriers to undertaking weight loss in infertile populations is evident, and future research should examine these issues further.

AB - BACKGROUND: The prevalence of obesity is increasing worldwide, with a corresponding increase in overweight and obese patients referred with infertility. This systematic review aimed to determine whether non-surgical weight reduction strategies result in an improvement in reproductive parameters affected by obesity, e.g. delayed time to pregnancy, oligozoospermia and azoospermia. No prior reviews have examined this within the general fertility population, or in both sexes.OBJECTIVE AND RATIONALE: Our objective was to answer the question: 'In overweight and obese women, men and couples seeking fertility treatment, what non-surgical weight-loss interventions have been used, and how effective are they at weight loss and improving reproductive outcomes?'SEARCH METHODS: An electronic search of MEDLINE, EMBASE and the Cochrane Library was performed for studies between January 1966 and March 2016. Text word and MESH search terms used related to infertility, weight and barriers to weight loss. Inclusion criteria were an intervention to change lifestyle evaluated in any study design in participants of either gender with an unfulfilled desire to conceive. Studies were excluded if they included participants not attempting pregnancy, with illnesses that might cause weight fluctuations, or studies evaluating bariatric surgery. Two reviewers performed data extraction and quality assessment using the Cochrane Risk of Bias Tool for randomized trials, and a ratified checklist (ReBIP) for non-randomized studies.OUTCOMES: A total of 40 studies were included, of which 14 were randomised control trials. Primary outcomes were pregnancy, live birth rate and weight change. In women, reduced calorie diets and exercise interventions were more likely than control interventions to result in pregnancy [risk ratio 1.59, 95% CI (1.01, 2.50)], and interventions resulted in weight loss and ovulation improvement, where reported. Miscarriage rates were not reduced by any intervention.WIDER IMPLICATIONS: Overweight and obese persons seeking fertility should be educated on the detrimental effects of fatness and the benefits of weight reduction, including improvement in pregnancy rates. A combination of a reduced calorie diet, by reducing fat and refined carbohydrate intake, and increased aerobic exercise should form the basis of programmes designed for such individuals. A lack of randomized studies in men and couples, and studies evaluating barriers to undertaking weight loss in infertile populations is evident, and future research should examine these issues further.

KW - Journal Article

KW - infertility

KW - obesity

KW - weight loss

KW - systematic review

KW - diet

KW - exercise

U2 - 10.1093/humupd/dmx027

DO - 10.1093/humupd/dmx027

M3 - Article

VL - 23

SP - 681

EP - 705

JO - Human Reproduction Update

JF - Human Reproduction Update

SN - 1355-4786

IS - 6

ER -