Successful weight loss interventions before in vitro fertilization: fat chance?

Lipotoxicity and Oocyte Quality in Mammals: Pathogenesis, Consequences, and Reversibility

Metabolic stress conditions are often characterized by upregulated lipolysis and subsequently increased serum free fatty acid (FFA) concentrations, leading to the uptake of FFAs by non-adipose tissues and impairment of their function. This phenomenon is known as lipotoxicity. The increased serum FFA concentrations are reflected in the ovarian follicular fluid, which can have harmful effects on oocyte development. Several studies using in vitro and in vivo mammalian models showed that altered oocyte metabolism, increased oxidative stress, and mitochondrial dysfunction are crucial mechanisms underlying this detrimental impact. Ultimately, this can impair offspring health through the persistence of defective mitochondria in the embryo, hampering epigenetic reprogramming and early development. In vitro and in vivo treatments to enhance oocyte mitochondrial function are increasingly being developed. This can help to improve pregnancy rates and safeguard offspring health in metabolically compromised individuals.

Belgian Fertility Clinic Staff Value Healthy Lifestyle Promotion but Lack Access to a Structured Lifestyle Modification Programme: An Observational Study

OBJECTIVES

Guidelines advise promoting a healthy lifestyle among patients with fertility problems as the lifestyle of women and men proved to be associated with their fertility. Australian fertility nurses were shown to lack access to structured lifestyle modification programmes, although they value healthy lifestyle promotion. This study aimed to examine whether gynaecologists also value promoting a healthy lifestyle and whether structured lifestyle modification programmes are available in Belgian fertility clinics.

DESIGN

An observational study was conducted among health care professionals (HCPs) working in Belgian fertility clinics.

PARTICIPANTS/MATERIALS, SETTING, METHODS

An Australian questionnaire on attitudes and practices related to promoting a healthy lifestyle among patients with fertility problems was reciprocally back-to-back translated and three open-ended questions were added. All HCPs of Belgian fertility clinics, including gynaecologists, fertility nurses/midwives, psychologists, and embryologists, were invited by e-mail to complete the questionnaire online. Responses to closed and open-ended questions were analysed with, respectively, descriptive statistics and qualitative thematic analysis. Finally, differences in perspectives between different groups of HCPs were explored.

RESULTS

A total of 50 fertility nurses/midwives, 42 gynaecologists, and 19 other HCPs completed the survey (n = 111). Regarding attitudes, all respondents valued informing patients about the impact of lifestyle on fertility. The vast majority of HCPs (n = 96; 86%) stated that fertility clinics have the responsibility to address unhealthy lifestyles prior to offering fertility treatment. Fertility nurses/midwives were significantly more likely than gynaecologists to state that fertility clinics have this responsibility (p = 0.040). Regarding practices, the patient's lifestyle was most commonly discussed by the gynaecologist (n = 107; 96%) during the first appointment (n = 105; 95%). The lifestyle factors that were being addressed, according to the vast majority of respondents, were smoking, weight, age, alcohol, and recreational drugs. Only three HCPs (from three different clinics) stated that their clinic offered a structured lifestyle modification programme. HCPs explained that they lacked the resources and expertise for offering a structured lifestyle modification programme.

LIMITATIONS

Response rates were limited, but the responding Belgian gynaecologists and fertility nurses/midwives confirmed the findings of the previous study in Australian fertility nurses.

CONCLUSIONS

HCPs working in Belgian fertility clinics value healthy lifestyle promotion but lack access to structured lifestyle modification programmes to implement in their daily clinical practice. Future studies should focus on developing and evaluating structured lifestyle modification programmes for patients with fertility problems.

Detrimental actions of obesity-associated advanced glycation end-products on endometrial epithelial cell proliferation are alleviated by antioxidants

RESEARCH QUESTION

Advanced glycation end-products (AGE) are elevated in the uterine environment of obese infertile women. Can the detrimental effects of AGE on endometrial epithelial cells be mitigated with therapeutics, and recapitulated in a more physiologically relevant primary model (organoids)?

DESIGN

Human endometrial epithelial cells (ECC-1) were exposed to AGE at concentrations physiologically representative of uterine fluid in lean or obese individuals, and three potential therapeutics: 25 nmol/l receptor for AGE (RAGE) antagonist FPS-ZM1, 100 μmol/l metformin, or a combination of antioxidants (10 μmol/l N-acetyl-l-cysteine, 10 μmol/l N-acetyl-l-carnitine and 5 μmol/l α-lipoic acid). Real-time cell analysis (xCELLigence, ACEA Biosciences) determined the rate of adhesion and proliferation. The proliferation of organoid-derived cells and secretion of cytokines from organoids was characterized in the presence of AGE (n = 5). The uterine fluid of women undergoing assisted reproduction was profiled for AGE-associated inflammatory markers (n = 77).

RESULTS

ECC-1 proliferation was reduced by AGE from obese versus lean conditions and vehicle control (P = 0.04 and P < 0.001, respectively), and restored to a proliferation corresponding to lean conditions by antioxidants. AGE influenced organoid derived primary endometrial epithelial cell proliferation in a donor-dependent manner. AGE increased the organoid secretion of the proinflammatory cytokine CXCL16 (P = 0.006). Clinically, CXCL16 correlated positively to maternal body mass index (R = 0.264, P = 0.021) and intrauterine glucose concentration (R = 0.736, P < 0.0001).

CONCLUSIONS

Physiologically relevant concentrations of AGE alter endometrial epithelial cell function. Antioxidants restore the rate of proliferation of AGE-treated endometrial epithelial (ECC-1) cells. Primary endometrial epithelial cells, cultured as organoids, demonstrate altered proliferation and CXCL16 secretion in the presence of AGE equimolar with the uterine fluid from obese individuals.

Effect of weight loss orientation on BMI in obese and overweight infertile patients

OBJECTIVE

The aim of this study was to evaluate the response to weight loss guidance in the anthropometric parameters of obesity and overweight infertile patients assisted fertilization treatment (high and low complexity).

METHODS

Retrospective cohort study. This survey was conducted in a population of overweight and obese infertile patients. In the first consultation at the assisted reproduction clinic (Human Reproduction Laboratory HC / UFG), obese and overweight patients were weighed, measured and instructed to lose weight and informed that being overweight could reduce the chances of success in the treatment.

RESULTS

We analyzed 56 overweight and obese patients admitted for infertility treatment at the Human Reproduction Center HC/UFG. The mean age of overweight and obese patients was 35.78 years, SD 3.70. After the orientation, only 8.92% of patients would achieve the normality rating for BMI, overweight 39.28% (decreased 14.29%), obesity I 37.5%, obesity II 10.71% and obesity III 3.57% (all degrees of obesity increased 1.79%). The mean weight of patients before and after guidance was statistically significant (p<0.0046). The mean values of BMI before and after guidance were also statistically significant (p<0.0038).

CONCLUSIONS

Weight loss guidance in this population had no effect on weight loss. On the contrary, the mean weight of patients after guidance was statistically higher than the mean in the first consultation (both weight and BMI). It is suggested that for obese and overweight infertile patients, in addition to guidance for reduction, an appointment with a nutritionist and/or endocrinologist should be immediately scheduled.

How effective are lifestyle interventions for overweight women trying to conceive?

PURPOSE OF REVIEW

To summarize and critically review the current knowledge on the effectiveness of lifestyle modifications for overweight women trying to conceive.

RECENT FINDINGS

Overweight is associated with a wide spectrum of disorders, which may directly or indirectly affect fertility [from menstrual cycle irregularities to a lower chance of live birth after assisted reproductive technology (ART) treatment]. Weight loss through nonpharmaceutical lifestyle interventions is achievable. Weight loss can normalize menstrual cycle irregularities and can increase fecundability. Pregnancy-associated risks, such as gestational diabetes can be decreased by preconception weight reduction.

SUMMARY

Weight loss through lifestyle changes (i.e., lower caloric intake and increased physical activity), may increase fecundability and may have a positive impact on the course of pregnancy, delivery, and neonatal outcomes. Accordingly, women should be motivated to reduce their weight before conception. However, the effectiveness of life-style intervention programs for women actively seeking medical support in achieving pregnancy has not convincingly been demonstrated. In the few randomized controlled trials (RCTs), selection bias for trial participation by patient motivation may have been present, yet participant attrition was still high and mean effects were small, casting doubts on the utility of such programs in routine care. Pharmacological and surgical intervention may be more effective or necessary complements to lifestyle intervention programs.

Obese outbred mice only partially benefit from diet normalization or calorie restriction as preconception care interventions to improve metabolic health and oocyte quality

STUDY QUESTION

Can diet normalization or a calorie-restricted diet for 2 or 4 weeks be used as a preconception care intervention (PCCI) in Western-type diet-induced obese Swiss mice to restore metabolic health and oocyte quality?

SUMMARY ANSWER

Metabolic health and oocyte developmental competence was already significantly improved in the calorie-restricted group after 2 weeks, while obese mice that underwent diet normalization showed improved metabolic health after 2 weeks and improved oocyte quality after 4 weeks.

WHAT IS KNOWN ALREADY

Maternal obesity is linked with reduced metabolic health and oocyte quality; therefore, infertile obese women are advised to lose weight before conception to increase pregnancy chances. However, as there are no univocal guidelines and the specific impact on oocyte quality is not known, strategically designed studies are needed to provide fundamental insights in the importance of the type and duration of the dietary weight loss strategy for preconception metabolic health and oocyte quality.

STUDY DESIGN, SIZE, DURATION

Outbred female Swiss mice were fed a control (CTRL) or high-fat/high-sugar (HF/HS) diet. After 7 weeks, some of the HF mice were put on two different PCCIs, resulting in four treatment groups: (i) only control diet for up to 11 weeks (CTRL_CTRL), (ii) only HF diet for up to 11 weeks (HF_HF), (iii) switch at 7 weeks from an HF to an ad libitum control diet (HF_CTRL) and (iv) switch at 7 weeks from an HF to a 30% calorie-restricted control diet (HF_CR) for 2 or 4 weeks. Metabolic health and oocyte quality were assessed at 2 and 4 weeks after the start of the intervention (n = 8 mice/treatment/time point).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Changes in body weight were recorded. To study the impact on metabolic health, serum insulin, glucose, triglycerides, total cholesterol and alanine aminotransferase concentrations were measured, and glucose tolerance and insulin sensitivity were analyzed at PCCI Weeks 2 and 4. The quality of in vivo matured oocytes was evaluated by assessing intracellular lipid droplet content, mitochondrial activity and localization of active mitochondria, mitochondrial ultrastructure, cumulus cell targeted gene expression and oocyte in vitro developmental competence.

MAIN RESULTS AND THE ROLE OF CHANCE

Significant negative effects of an HF/HS diet on metabolic health and oocyte quality were confirmed (P < 0.05). HF_CTRL mice already showed restored body weight, serum lipid profile and glucose tolerance, similar to the CTRL_CTRL group after only 2 weeks of PCCI (P < 0.05 compared with HF_HF) while insulin sensitivity was not improved. Oocyte lipid droplet volume was reduced at PCCI Week 2 (P < 0.05 compared with HF_HF), while mitochondrial localization and activity were still aberrant. At PCCI Week 4, oocytes from HF_CTRL mice displayed significantly fewer mitochondrial ultrastructural abnormalities and improved mitochondrial activity (P < 0.05), while lipid content was again elevated. The in vitro developmental capacity of the oocytes was improved but did not reach the levels of the CTRL_CTRL mice. HF_CR mice completely restored cholesterol concentrations and insulin sensitivity already after 2 weeks. Other metabolic health parameters were only restored after 4 weeks of intervention with clear signs of fasting hypoglycemia. Although all mitochondrial parameters in HF_CR oocytes stayed aberrant, oocyte developmental competence in vitro was completely restored already after 2 weeks of intervention.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

In this study, we applied a relevant HF/HS Western-type diet to induce obesity in an outbred mouse model. Nevertheless, physiological differences should be considered when translating these results to the human setting. However, the in-depth study and follow-up of the metabolic health changes together with the strategic implementation of specific PCCI intervals (2 and 4 weeks) related to the duration of the mouse folliculogenesis (3 weeks), should aid in the extrapolation of our findings to the human setting.

WIDER IMPLICATIONS OF THE FINDINGS

Our study results with a specific focus on oocyte quality provide important fundamental insights to be considered when developing preconception care guidelines for obese metabolically compromised women wishing to become pregnant.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the Flemish Research Fund (FWO-SB grant 1S25020N and FWO project G038619N). The authors declare there are no conflicts of interest.

[Obesity affects the chances of birth after frozen-thawed blastocyst transfer]

OBJECTIVES

Both the number of frozen-thawed embryo transfers and the incidence of obesity have increased sharply in recent years in Assisted Reproductive Technology (ART) centers. The objective of our study is therefore to evaluate the impact of female obesity on pregnancy outcomes for frozen-thawed embryo transfer at blastocyst stage.

METHODS

This is a single-center retrospective study conducted between January 1, 2016, and December 31, 2019, in our Assisted Reproduction Center in Calais. All consecutive cycles of frozen embryo transfers at blastocyst stage with artificial cycle were included. A total of 296 cycles could be included corresponding to 220 cycles realized in normal Body Mass Index (BMI) patients (18.5-24.9kg/m²) and 76 in obese patients (BMI≥30kg/m²).

RESULTS

Live birth rates and implantation rates were significantly lower in obese patients compared with patients with a normal BMI (respectively 9.2 % vs. 22.3 % and 10 % vs. 20.8 %, P=0.01 and P<0.01).

CONCLUSIONS

Therefore, our study showed that obesity is associated with a lower rate of live birth and implantation following frozen-thawed blastocyst transfers in artificial cycles. This could be explained by different factors that can be both embryonic and/or extra-embryonic.

The Effect of Dietary Patterns on Clinical Pregnancy and Live Birth Outcomes in Men and Women Receiving Assisted Reproductive Technologies: A Systematic Review and Meta-Analysis

The nutritional status of reproductive-aged couples can have a significant impact on fertility status, but the effect of dietary patterns on pregnancy outcomes in people using assisted reproductive technologies (ARTs) is currently unknown. This review aimed to synthesize the published research investigating the relation between preconception dietary patterns and clinical pregnancy or live birth in men and women of reproductive age undergoing ART. Six electronic databases were systematically searched for original research published between January 1978 and June 2021. Original research reporting on the effect of predefined dietary patterns on either clinical pregnancy and/or live birth rates following in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) in men and women aged 18-49 y was eligible for inclusion. Studies were assessed for risk of bias according to the Cochrane guidelines. Included studies underwent qualitative and quantitative synthesis using random-effects model meta-analyses. Thirteen studies (12 cohort studies, 1 randomized controlled trial) reporting on 3638 participants (93% female) were included in the review. All studies had a moderate-high risk of bias. In individual studies, maternal adherence to 4 dietary patterns [Mediterranean diet (RR: 1.22; 95% CI: 1.05, 1.43), novel profertility diet (OR: 1.43; 95% CI: 1.19, 1.72), Iranian traditional medicine diet (OR: 3.9; 95% CI: 1.2, 12.8), Dutch national dietary recommendations diet (OR: 1.65; 95% CI: 1.08, 2.52)] was associated with increased likelihood of achieving a clinical pregnancy, while 2 dietary patterns [novel profertility diet (OR: 1.53; 95% CI: 1.26, 1.85), Mediterranean diet (RR: 1.25; 95% CI: 1.07, 1.45)] were associated with increased probability of live birth. Meta-analyses showed an association between adherence to the Mediterranean dietary pattern and live birth across 2 studies (OR: 1.98; 95% CI: 1.17, 3.35; I2 = 29%, n = 355), but no association with clinical pregnancy. As the relation between dietary patterns and ART outcomes is currently inconsistent, higher-quality nutrition research is required to further explore this emerging field of interest (PROSPERO registration: CRD42020188194).

Body mass index is associated with miscarriage rate and perinatal outcomes in cycles with frozen-thawed single blastocyst transfer: a retrospective cohort study

Background

The association between body mass index (BMI) and IVF cycle outcomes remain inconclusive. In addition, the impact of BMI on perinatal outcomes has been less well-studied. The aim of this study was to assess the effects of BMI on pregnancy outcomes, as well as maternal and neonatal outcomes.

Methods

This was a retrospective cohort study on 10,252 frozen-thawed cycles with single blastocyst transfer between January 2016 and December 2019. Patients were divided into four groups: underweight (< 18.5 kg/m²), normal-weight (18.5–24 kg/m²), overweight (24–28 kg/m²), and obesity (≥ 28 kg/m²), according to the Chinese classification. Multivariate logistic regression and multivariate general linear model were used for statistical analysis.

Results

The rates of live birth and clinical pregnancy were comparable among groups. Miscarriage rate was higher in the obese women than that in the normal controls (27.51 vs. 20.91%, aOR = 1.453 (1.066–1.982)). Using the normal-weight women as reference, the underweight women had lower incidences of preterm birth (6.97 vs. 11.19%, aOR = 0.611 (0.422–0.884)), macrosomia (4.90 vs. 8.65%, aOR = 0.544 (0.353–0.837)) and large-for-gestational age (LGA, 11.18 vs. 16.54%, aOR = 0.643 (0.477–0.866)); the overweight women had higher prevalence of gestational diabetes (6.56 vs. 3.82%, aOR = 1.744 (1.232–2.468)), hypertension (4.42 vs. 2.32%, aOR = 1.822 (1.186–2.800)), macrosomia (12.93 vs. 8.65%, aOR = 1.596 (1.240–2.054)) and LGA (23.22 vs. 16.54%, aOR = 1.549 (1.270–1.890)); the obese women had higher incidences of preterm birth (16.87 vs. 11.19%, aOR = 1.646 (1.068–2.536)), cesarean delivery (93.98 vs. 87.91%, aOR = 2.078 (1.083–3.987)), gestational hypertension (4.82 vs. 2.32%, aOR = 2.138 (1.005–4.547)), macrosomia (14.88 vs. 8.65%, aOR = 1.880 (1.192–2.964)) and LGA (25.60 vs. 16.54%, aOR = 1.764 (1.218–2.555)).

Conclusions

BMI has no significant effect on the chance of pregnancy or live birth, but obesity increases the risk of miscarriage. Underweight is associated with better maternal and neonatal outcomes, while overweight and obesity are associated with worse maternal and neonatal outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04443-2.

Sonographic prediction of successful embryonic implantation in in-vitro fertilization and embryo transfer cycle procedures, using a multi-parameter approach

INTRODUCTION

The success of in vitro fertilization and embryo transfer (IVF-ET) cycles depend on maternal age, embryo quality and uterine receptivity. Prediction of embryonic implantation prior to IVF has become crucial in counseling patients due to the cost of failed procedure, in terms of huge financial expenditure, time taken for the procedure, associated health risks and psychological effects following unfulfilled expectation. The objective of this study was therefore to develop a scoring protocol and consequently, a predictive model for a successful embryonic implantation in IVF-ET cycles using maternal demographic, endometrial, ovarian, and hormonal parameters as tools for clinical decision and patient counseling.

MATERIAL AND METHODS

The body mass index (BMI), age, endometrial pattern and thickness, antral follicle count, (AFC) and anti-Mullerian hormone (AMH) concentration of 295 women between the ages of 18-45 years were evaluated prior to IVF- ET at a fertility clinic in Lagos, Nigeria. The AFC, endometrial pattern and thickness were determined sonographically and the AMH assayed, using ELISA test kits. Multiple regression analysis was used to determine the contribution of each parameter to the likelihood of a successful implantation, and a 4 point rating scale was developed based on the relative contribution of each parameter. Scores were then assigned based on the strength of each predictor variable to implantation rates.

RESULTS

Eighteen women that conceived had a full score of 20, while five that failed to conceive scored below 9. Chi square test indicated that endometrial pattern, thickness, age, AFC and AMH are highly significant in predicting embryonic implantation at IVF, while BMI was insignificant (r = -1.831, p = 0.094).

CONCLUSION

The prediction model demonstrated a positive correlation between the cumulative score and implantation rate. The use of the scoring system could provide a guide to clinicians to predict the success rate of each IVF-ET procedure prior to commencement of treatment.

IMPLICATIONS FOR PRACTICE

The availability of this prediction model provides a counselling tool for physicians to IVF clients which ensures improved confidences level and reduced disappointments from failures in successful implantation and embryonic transfer including its associated financial costs and health risks.

The effectiveness of weight-loss lifestyle interventions for improving fertility in women and men with overweight or obesity and infertility: A systematic review update of evidence from randomized controlled trials

Being overweight or obese can have a negative impact on fertility outcomes. This systematic review updates randomized controlled trial (RCT) findings on the effectiveness of weight loss interventions in reducing weight and improving reproductive outcomes of women and men with overweight or obesity and infertility. Eligible studies, published since the last review, were identified by searching databases from March 20, 2016 until March 31, 2020. RCTs involving any type of lifestyle intervention were considered. Eight RCTs were identified and aggregated with seven RCTs included in our previous review. Meta-analyses revealed that women randomized to a combined diet and exercise intervention were more likely to become pregnant, risk ratio (RR) = 1.87 (95% CI 1.20, 2.93) and achieve a live birth RR = 2.20 (95% CI 1.23, 3.94), compared to women in control groups who received no or minimal intervention. This pattern was not replicated in trials where control groups received immediate access to assisted reproductive technology (ART). No eligible randomized trials involving men were identified. Data were largely obtained from small scale studies. Better designed, adequately powered, robust randomized trials are needed to better understand the effect of weight loss interventions on reproductive outcomes in both women and men.

High-sensitivity C-reactive protein is not independently associated with self-reported infertility in National Health and Nutrition Examination Survey 2015–2018 data

Objective

To study the association between high-sensitivity C-reactive protein (hs-CRP) and infertility among reproductive-age women while controlling for obesity and other metabolic markers. Previous studies found a link between infertility and cardiovascular diseases (CVDs). C-reactive protein is a sensitive marker of CVDs, and its levels are affected by obesity.

Design/Setting

We conducted a cross-sectional study using national data from 2015 through 2018.

Patients

A total of 940 women aged 20–45 years who self-reported infertility, had hs-CRP values measured, and did not have CRP >10 mg/L, asthma, arthritis, bronchitis, thyroid disease, bilateral oophorectomy, hysterectomy, and who were not breastfeeding or pregnant, premenarchal at the time of study or had menarche after the age of 20.

Interventions

N/A.

Main outcome measure(s)

Infertility status (ever reporting inability to conceive with 12 months of trying to become pregnant).

Results

In comparison to noninfertile women, self-reported infertile women had higher mean of hs-CRP (3.11 mg/L vs. 2.40 mg/L) and higher percentage of moderate/high hs-CRP values (77.0% vs 58.8%). However, after adjusting for metabolic markers, there was a nonsignificant association between moderate/high hs-CRP and self-reported infertility in the multivariable logistic regression analysis. Odds ratio estimates of the association between hs-CRP and infertility increased over 40% after removing obesity measures and/or high-density lipoprotein from regression models.

Conclusion

There was no association between hs-CRP and self-reported infertility after controlling for obesity measures and other risk factors for CVDs in a sample of U.S. women aged 20–45 years.

Body mass index and subfertility: multivariable regression and Mendelian randomization analyses in the Norwegian Mother, Father and Child Cohort Study

STUDY QUESTION

What is the association between BMI and subfertility?

SUMMARY ANSWER

We observed a J-shaped relationship between BMI and subfertility in both sexes, when using both a standard multivariable regression and Mendelian randomization (MR) analysis.

WHAT IS KNOWN ALREADY

High BMI in both women and men is associated with subfertility in observational studies and this relationship is further substantiated by a few small randomized controlled trials of weight reduction and success of assisted reproduction. Women with low BMI also have lower conception rates with assisted reproduction technologies.

STUDY DESIGN, SIZE, DURATION

Cohort study (the Norwegian Mother, Father and Child Cohort Study), 28 341 women and 26 252 men, recruited from all over Norway between 1999 and 2008.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women (average age 30, average BMI 23.1 kg/m2) and men (average age 33, average BMI 25.5 kg/m2) had available genotype data and provided self-reported information on time-to-pregnancy and BMI. A total of 10% of couples were subfertile (time-to-pregnancy ≥12 months).

MAIN RESULTS AND THE ROLE OF CHANCE

Our findings support a J-shaped association between BMI and subfertility in both sexes using multivariable logistic regression models. Non-linear MR validated this relationship. A 1 kg/m2 greater genetically predicted BMI was linked to 18% greater odds of subfertility (95% CI 5% to 31%) in obese women (≥30.0 kg/m2) and 15% lower odds of subfertility (-24% to -2%) in women with BMI <20.0 kg/m2. A 1 kg/m2 higher genetically predicted BMI was linked to 26% greater odds of subfertility (8-48%) among obese men. Low genetically predicted BMI values were also related to greater subfertility risk in men at the lower end of the BMI distribution. A genetically predicted BMI of 23 and 25 kg/m2 was linked to the lowest subfertility risk in women and men, respectively.

LIMITATIONS, REASONS FOR CAUTION

The main limitations of our study were that we did not know whether the subfertility was driven by the women, men or both; the exclusive consideration of individuals of northern European ancestry; and the limited amount of participants with obesity or BMI values <20.0 kg/m2.

WIDER IMPLICATIONS OF THE FINDINGS

Our results support a causal effect of obesity on subfertility in women and men. Our findings also expand the current evidence by indicating that individuals with BMI values <20 kg/m2 may have an increased risk of subfertility. These results suggest that BMI values between 20 and 25 kg/m2 are optimal for a minimal risk of subfertility.

STUDY FUNDING/COMPETING INTEREST(S)

The MoBa Cohort Study is supported by the Norwegian Ministry of Health and Care Services and the Norwegian Ministry of Education and Research. This project received funding from the European Research Council under the European Union's Horizon 2020 research and innovation program (grant agreement No 947684). It was also partly supported by the Research Council of Norway through its Centres of Excellence funding scheme, project number 262700. Open Access funding was provided by the Folkehelseinstituttet/Norwegian Institute of Public Health. D.A.L. is a UK National Institute for Health Research Senior Investigator (NF-SI-0611-10196) and is supported by the US National Institutes of Health (R01 DK10324) and a European Research Council Advanced Grant (DevelopObese; 669545). The funders had no role in the collection, analysis and interpretation of data; in the writing of the report; or in the decision to submit the article for publication. D.A.L. receives (or has received in the last 10 years) research support from National and International government and charitable bodies, Roche Diagnostics and Medtronic for research unrelated to the current work. The rest of the authors declare that no competing interests exist.

TRIAL REGISTRATION NUMBER

N/A.

Diet normalization or caloric restriction as a preconception care strategy to improve metabolic health and oocyte quality in obese outbred mice

BACKGROUND

Maternal metabolic disorders are linked to reduced metabolic health and oocyte quality. Obese women are advised to lose weight before conception to increase pregnancy chances. However, as human studies show no univocal guidelines, more research is necessary to provide fundamental insights in the consequences of dietary weight loss on oocyte quality. Therefore, we investigated the impact of diet normalization or calorie restricted diet for two, four or six weeks, as preconception care intervention (PCCI), in obese mice on metabolic health and oocyte quality.

METHODS

Outbred female mice were fed a control (CTRL) or high-fat (HF) diet for 7 weeks (7w). Afterwards, HF-mice were put on different PCCIs, resulting in four treatment groups: 1) control diet up to 13w, 2) HF diet up to 13w (HF_HF), switch from a HF (7w) to 3) an ad libitum control diet (HF_CTRL) or 4) 30% calorie restricted control diet (HF_CR) for two, four or six weeks. Body weight, metabolic health, oocyte quality and overall fertility results were assessed.

RESULTS

Negative effects of HF diet on metabolic health, oocyte quality and pregnancy rates were confirmed. HF_CTRL mice progressively improved insulin sensitivity, glucose tolerance, serum insulin and cholesterol from PCCI w2 to w4. No further improvements in metabolic health were present at PCCI w6. However, PCCI w6 showed best oocyte quality improvements. Mature oocytes still showed elevated lipid droplet volume and mitochondrial activity but a significant reduction in ROS levels and ROS: active mitochondria ratio compared with HF_HF mice. HF_CR mice restored overall insulin sensitivity and glucose tolerance by PCCI w4. However, serum insulin, cholesterol and ALT remained abnormal. At PCCI w6, glucose tolerance was again reduced. However, only at PCCI w6, oocytes displayed reduced ROS levels and restored mitochondrial activity compared with HF_HF mice. In addition, at PCCI w6, both PCCI groups showed decreased mitochondrial ultrastructural abnormalities compared with the HF_HF group and restored pregnancy rates.

CONCLUSIONS

Diet normalization for 4 weeks showed to be the shortest, most promising intervention to improve metabolic health. Most promising improvements in oocyte quality were seen after 6 weeks of intervention in both PCCI groups. This research provides fundamental insights to be considered in developing substantiated preconception guidelines for obese women planning for pregnancy.

Lifestyle intervention prior to IVF does not improve embryo utilization rate and cumulative live birth rate in women with obesity: a nested cohort study

STUDY QUESTION

Does lifestyle intervention consisting of an energy-restricted diet, enhancement of physical activity and motivational counseling prior to IVF improve embryo utilization rate (EUR) and cumulative live birth rate (CLBR) in women with obesity?

SUMMARY ANSWER

A 6-month lifestyle intervention preceding IVF improved neither EUR nor CLBR in women with obesity in the first IVF treatment cycle where at least one oocyte was retrieved.

WHAT IS KNOWN ALREADY

A randomized controlled trial (RCT) evaluating the efficacy of a low caloric liquid formula diet (LCD) preceding IVF in women with obesity was unable to demonstrate an effect of LCD on embryo quality and live birth rate: in this study, only one fresh embryo transfer (ET) or, in case of freeze-all strategy, the first transfer with frozen-thawed embryos was reported. We hypothesized that any effect on embryo quality of a lifestyle intervention in women with obesity undergoing IVF treatment is better revealed by EUR and CLBR after transfer of all fresh and frozen-thawed embryos.

STUDY DESIGN, SIZE, DURATION

This is a nested cohort study within an RCT, the LIFEstyle study. The original study examined whether a 6-month lifestyle intervention prior to infertility treatment in women with obesity improved live birth rate, compared to prompt infertility treatment within 24 months after randomization. In the original study between 2009 and 2012, 577 (three women withdrew informed consent) women with obesity and infertility were assigned to a lifestyle intervention followed by infertility treatment (n = 289) or to prompt infertility treatment (n = 285).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Only participants from the LIFEstyle study who received IVF treatment were eligible for the current analysis. In total, 137 participants (n = 58 in the intervention group and n = 79 in the control group) started the first cycle. In 25 participants, the first cycle was cancelled prior to oocyte retrieval mostly due to poor response. Sixteen participants started a second or third consecutive cycle. The first cycle with successful oocyte retrieval was used for this analysis, resulting in analysis of 51 participants in the intervention group and 72 participants in the control group. Considering differences in embryo scoring methods and ET day strategy between IVF centers, we used EUR as a proxy for embryo quality. EUR was defined as the proportion of inseminated/injected oocytes per cycle that was transferred or cryopreserved as an embryo. Analysis was performed per cycle and per oocyte/embryo. CLBR was defined as the percentage of participants with at least one live birth from the first fresh and subsequent frozen-thawed ET(s). In addition, we calculated the Z-score for singleton neonatal birthweight and compared these outcomes between the two groups.

MAIN RESULTS AND THE ROLE OF CHANCE

The overall mean age was 31.6 years and the mean BMI was 35.4 ± 3.2 kg/m² in the intervention group, and 34.9 ± 2.9 kg/m² in the control group. The weight change at 6 months was in favor of the intervention group (mean difference in kg vs the control group: −3.14, 95% CI: −5.73 to −0.56). The median (Q25; Q75) number of oocytes retrieved was 4.00 (2.00; 8.00) in the intervention group versus 6.00 (4.00; 9.75) in the control group, and was not significantly different, as was the number of oocytes inseminated/injected (4.00 [2.00; 8.00] vs 6.00 [3.00; 8.75]), normal fertilized embryos (2.00 [0.50; 5.00] vs 3.00 [1.00; 5.00]) and the number of cryopreserved embryos (2.00 [1.25; 4.75] vs 2.00 [1.00; 4.00]). The median (Q25; Q75) EUR was 33.3% (12.5%; 60.0%) in the intervention group and 33.3% (16.7%; 50.0%) in the control group in the per cycle analysis (adjusted B: 2.7%, 95% CI: −8.6% to 14.0%). In the per oocyte/embryo analysis, in total, 280 oocytes were injected or inseminated in the intervention group, 113 were utilized (transferred or cryopreserved, EUR = 40.4%); in the control group, EUR was 30.8% (142/461). The lifestyle intervention did not significantly improve EUR (adjusted odds ratio [OR]: 1.36, 95% CI: 0.94–1.98) in the per oocyte/embryo analysis, taking into account the interdependency of the oocytes per participant. CLBR was not significantly different between the intervention group and the control group after adjusting for type of infertility (male factor and unexplained) and smoking (27.5% vs 22.2%, adjusted OR: 1.03, 95% CI: 0.43–2.47). Singleton neonatal birthweight and Z-score were not significantly different between the two groups.

LIMITATIONS, REASONS FOR CAUTION

This study is a nested cohort study within an RCT, and no power calculation was performed. The randomization was not stratified for indicated treatment, and although we corrected our analyses for baseline differences, there may be residual confounding. The limited absolute weight loss and the short duration of the lifestyle intervention might be insufficient to affect EUR and CLBR.

WIDER IMPLICATIONS OF THE FINDINGS

Our data do not support the hypothesis of a beneficial short-term effect of lifestyle intervention on EUR and CLBR after IVF in women with obesity, although more studies are needed as there may be a potential clinically relevant effect on EUR.

STUDY FUNDING/COMPETING INTEREST(S)

The study was supported by a grant from ZonMw, the Dutch Organization for Health Research and Development (50-50110-96-518). A.H. has received an unrestricted educational grant from Ferring pharmaceuticals BV, The Netherlands. B.W.J.M. is supported by an NHMRC Investigator grant (GNT1176437). B.W.J.M. reports consultancy for Guerbet, has been a member of the ObsEva advisory board and holds Stock options for ObsEva. B.W.J.M. has received research funding from Guerbet, Ferring and Merck. F.J.M.B. reports personal fees from membership of the external advisory board for Merck Serono and a research support grant from Merck Serono, outside the submitted work.

TRIAL REGISTRATION NUMBER

The LIFEstyle RCT was registered at the Dutch trial registry (NTR 1530). https://www.trialregister.nl/trialreg/admin/rctview.asp?TC=1530.

Effect of Orlistat on Live Birth Rate in Overweight or Obese Women Undergoing IVF-ET: A Randomized Clinical Trial

CONTEXT

Obesity management prior to infertility treatment remains a challenge. To date, results from randomized clinical trials involving weight loss by lifestyle interventions have shown no evidence of improved live birth rate.

OBJECTIVE

This work aimed to determine whether pharmacologic weight-loss intervention before in vitro fertilization and embryo transfer (IVF-ET) can improve live birth rate among overweight or obese women.

METHODS

We conducted a randomized, double-blinded, placebo-controlled trial across 19 reproductive medical centers in China, from July 2017 to January 2019. A total of 877 infertile women scheduled for IVF who had a body mass index of 25 or greater were randomly assigned to receive orlistat (n = 439) or placebo (n = 438) treatment for 4 to 12 weeks. The main outcome measurement was the live birth rate after fresh ET.

RESULTS

The live birth rate was not significantly different between the 2 groups (112 of 439 [25.5%] with orlistat and 112 of 438 [25.6%] with placebo; P = .984). No significant differences existed between the groups as to the rates of conception, clinical pregnancy, or pregnancy loss. A statistically significant increase in singleton birth weight was observed after orlistat treatment (3487.50 g vs 3285.17 g in the placebo group; P = .039). The mean change in body weight during the intervention was -2.49 kg in the orlistat group, as compared to -1.22 kg in the placebo group, with a significant difference (P = .005).

CONCLUSION

Orlistat treatment, prior to IVF-ET, did not improve the live birth rate among overweight or obese women, although it was beneficial for weight reduction.

Pre-Conception Interventions for Subfertile Couples Undergoing Assisted Reproductive Technology Treatment: Modeling Analysis

Background

Approximately 1 in 7 couples experience subfertility, many of whom have lifestyles that negatively affect fertility, such as poor nutrition, low physical activity, obesity, smoking, or alcohol consumption. Reducing lifestyle risk factors prior to pregnancy or assisted reproductive technology treatment contributes to the improvement of reproductive health, but cost-implications are unknown.

Objective

The goal of this study was to evaluate reproductive, maternal pregnancy, and birth outcomes, as well as the costs of pre-conception lifestyle intervention programs in subfertile couples and obese women undergoing assisted reproductive technology.

Methods

Using a hypothetical model based on quantitative parameters from published literature and expert opinion, we evaluated the following lifestyle intervention programs: (1) Smarter Pregnancy, an online tool; (2) LIFEstyle, which provides outpatient support for obese women; (3) concurrent use of both Smarter Pregnancy and LIFEstyle for obese women; (4) smoking cessation in men; and (5) a mindfulness mental health support program using group therapy sessions. The model population was based on data from the Netherlands.

Results

All model-based analyses of the lifestyle interventions showed a reduction in the number of in vitro fertilization, intracytoplasmic sperm injection, or intrauterine insemination treatments required to achieve pregnancy and successful birth for couples in the Netherlands. Smarter Pregnancy was modeled to have the largest increase in spontaneous pregnancy rate (13.0%) and the largest absolute reduction in potential assisted reproductive technology treatments. Among obese subfertile women, LIFEstyle was modeled to show a reduction in the occurrence of gestational diabetes, maternal hypertensive pregnancy complications, and preterm births by 4.4%, 3.8%, and 3.0%, respectively, per couple. Modeled cost savings per couple per year were €41 (US $48.66), €360 (US $427.23), €513 (US $608.80), €586 (US $695.43), and €1163 (US $1380.18) for smoking cessation, mindfulness, Smarter Pregnancy, combined Smarter Pregnancy AND LIFEstyle, and LIFEstyle interventions, respectively.

Conclusions

Although we modeled the potential impact on reproductive outcomes and costs of fertility treatment rather than collecting real-world data, our model suggests that of the lifestyle interventions for encouraging healthier behaviors, all are likely to be cost effective and appear to have positive effects on reproductive, maternal pregnancy, and birth outcomes. Further real-world data are required to determine the cost-effectiveness of pre-conception lifestyle interventions, including mobile apps and web-based tools that help improve lifestyle, and their effects on reproductive health. We believe that further implementation of the lifestyle app Smarter Pregnancy designed for subfertile couples seeking assistance to become pregnant is likely to be cost-effective and would allow reproductive health outcomes to be collected.

Potential Adverse Effects of Female and Male Obesity on Fertility: A Narrative Review

CONTEXT

Despite several studies documenting that obesity affects female and male fertility and leads to multiple adverse reproductive outcomes, the mechanisms involved are not elucidated. We aimed to summarize the potential adverse effects of female and male obesity, as well as the impact of weight loss on their fertility status.

EVIDENCE ACQUISITION

This review summarizes papers investigating the potential adverse effects of female and male obesity and the impact of weight-loss interventions on fertility among reproductive age populations. PubMed, Scopus, Web of Science, and Google Scholar databases were searched for retrieving studies published up to November 2019 on obesity/overweight among reproductive age populations.

RESULTS

The review of 68 studies revealed that female and male obesity/overweight increases the risk of sub-fecundity and infertility. The destructive effects of female obesity on reproduction are attributed to a variety of ovarian and extra-ovarian factors. In women with overweight or obesity, the time taken to conceive is longer, and they have a decreased fertility rate, increased requirement for gonadotropins, and higher miscarriage rate when compared to those with normal weight. Male obesity may lead to subfertility, mainly because of the disruption of the hypothalamus-pituitary-gonadal (HPG) axis, increased testicular temperature, impairment of the physical and molecular structure of sperm, decreased sperm quality, and erectile dysfunction due to peripheral vascular disease. Most studies recommend lifestyle interventions as first-line therapy in the general population of women and men with obesity and infertility.

CONCLUSIONS

This study shows the negative effects of female and male overweight and obesity on fertility. Therefore, educational interventions on the adverse effects of obesity and the benefits of weight reduction, such as increasing pregnancy rate, should be considered for couples seeking fertility.

Effect of body mass index on pregnancy outcomes in a freeze-all policy: an analysis of 22,043 first autologous frozen-thawed embryo transfer cycles in China

BACKGROUND

Abnormal BMI is associated with discouraging IVF outcomes in fresh autologous or oocyte donor cycles, whether or not such a relation also holds true for women undergoing frozen-thawed embryo transfer (FET) remains unknown. In addition, it remains unclear the detrimental effect of abnormal BMI on IVF outcomes occurs at the level of ovary or endometrium.

METHODS

A retrospective study involved 22,043 first FET cycles of all women who had undergone a freeze-all policy during the period from January 2010 to June 2017. To control for the embryo factor, our analysis was restricted to women with high-quality embryo transfer. The main outcome measure was live birth rate per embryo transfer. The secondary endpoints included rates of implantation, clinical pregnancy, multiple pregnancy, and pregnancy loss. Multivariate logistic regression analysis was performed to detect the independent effect of BMI on live birth rate after adjusting for important confounding variables.

RESULTS

In the crude analysis, reproductive outcomes were similar between underweight women and normal-weight controls whereas all parameter outcomes were significantly worse in patients with obesity. After adjustment for a number of confounding factors, underweight women had a marginally significant decrease in rates of implantation (adjusted odds ratio (aOR) 0.91; 95% CI 0.85-0.96), clinical pregnancy (aOR 0.91; 95% CI 0.83-0.99), and live birth (aOR 0.91; 95% CI 0.83-0.99) as compared to the women with normal weight. Obesity was significantly associated with decreased implantation (aOR 0.80; 95% CI 0.73-0.87), clinical pregnancy (aOR 0.81; 95% CI 0.71-0.91), and live birth rates (aOR 0.70; 95% CI 0.62-0.80). Moreover, the pregnancy loss rate, both in the first (aOR 1.46; 95% CI 1.15-1.87) and in the second trimester (aOR 2.76; 95% CI 1.67-4.58), was significantly higher in the obesity group than that in the reference group.

CONCLUSIONS

Among women undergoing first FET with high-quality embryo transfer, low BMI has limited impact on pregnancy and live birth rates. On the contrary, obesity was associated with worse IVF outcomes. Our findings further highlighted that endometrial receptivity played an important role in the poor reproductive outcomes of women with abnormal weight status.

Female subfertility

Subfertility is common and affects one in six couples, half of whom lack an explanation for their delay in conceiving. Developments in the diagnosis and treatment of subfertility over the past 50 years have been truly remarkable. Indeed, current generations of couples with subfertility are more fortunate than previous generations, as they have many more opportunities to become parents. The timely access to effective treatment for subfertility is important as many couples have a narrow window of opportunity before the age-related effects of subfertility limit the likelihood of success. Assisted reproduction can overcome the barriers to fertility caused by tubal disease and low sperm count, but little progress has been made in reducing the effect of increasing age on ovarian function. The next 5-10 years will likely see further increases in birth rates in women with subfertility, a greater awareness of lifestyle factors and a possible refinement of current assisted reproduction techniques and the development of new ones. Such progress will bring challenging questions regarding the potential benefits and harms of treatments involving germ cell manipulation, artificial gametes, genetic screening of embryos and gene editing of embryos. We hope to see a major increase in fertility awareness, access to safe and cost-effective fertility care in low-income countries and a reduction in the current disparity of access to fertility care.

A Slower Age-Related Decline in Treatment Outcomes After the First Ovarian Stimulation for in vitro Fertilization in Women With Polycystic Ovary Syndrome

Background: Polycystic ovary syndrome (PCOS) patients have a better ovarian reserve and age-related improvement in endocrine disturbances than non-PCOS patients. The effects of age on in vitro fertilization (IVF) treatment outcomes associated with cumulative live birth rate (CLBR) remain unclear. Objectives: To study the effect of age on CLBR after the first ovarian stimulation in IVF in PCOS patients. Method: This retrospective cohort study included 3,502 PCOS patients and 18,596 patients with tubal factor infertility, who underwent their first IVF cycles and subsequent frozen embryo transfer (ET) attempts. The primary outcome was CLBR associated with a single stimulation cycle and secondary outcomes included the implantation rate, clinical pregnancy rate, live birth rate (LBR), large for gestational age (LGA) rate, small for gestational age (SGA) rate, and preterm birth (PTB) rate of fresh ET cycles. Results: PCOS patients over 40 years had a higher implantation rate (27.8 vs. 15.7%, P < 0.05), clinical pregnancy rate (51.4 vs. 26.1%, P < 0.05), LBR (42.3 vs. 18.2%, P < 0.05), and CLBR (50.0 vs. 21.5%, P < 0.05) than non-PCOS patients over 40 years. These rates were comparable between PCOS patients aged 35 to 40 years and those aged over 40 years (P = 0.263, 0.385, and 0.112, respectively). The changes in the implantation rate, clinical pregnancy rate, and CLBR by age were slower for PCOS patients than for non-PCOS patients (all P < 0.05). Among PCOS patients less than 35 years, BMI was negatively associated with CLBR [aOR: 0.961 (0.939-0.985); P < 0.05]; however, among PCOS patients over 35 years, instead of BMI (P = 0.353), age [aOR: 0.891 (0.803-0.990); P < 0.05] and the number of oocytes retrieved [aOR: 1.093 (1.002-1.078); P < 0.05] were significantly associated with CLBR. No significant differences in LGA, LGA, or PTB were detected between PCOS and non-PCOS patients over 35 years (all P > 0.05). Conclusions: The declines in treatment outcomes with age are slower for PCOS patients than for non-PCOS patients. For patients over 40 years, PCOS patients have reproductive advantages over non-PCOS patients. In contrast to younger PCOS patients (<35 years), older PCOS patients (≥35 years) may benefit less from taking time to lose weight before IVF treatment, and the immediate initiation of assisted reproductive treatment is essential.