Systematic review and meta-analysis of the impact of preconception lifestyle interventions on fertility, obstetric, fetal, anthropometric and metabolic outcomes in men and women

STUDY QUESTION

What is the impact of preconception lifestyle interventions on live birth, birth weight and pregnancy rate?

SUMMARY ANSWER

Lifestyle interventions showed benefits for weight loss and increased natural pregnancy rate, but not for live birth or birth weight.

WHAT IS KNOWN ALREADY

Evidence on the practice and content of preconception counseling and interventions is variable and limited.

STUDY DESIGN, SIZE, DURATION

Systematic review and meta-analysis (MA). Main search terms were those related to preconception lifestyle. Database searched were Ovid MEDLINE(R), EBM Reviews, PsycINFO, EMBASE and CINAHL Plus. No language restriction was placed on the published articles. The final search was performed on 10 January 2017.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Participants were non-pregnant women of childbearing age intent on conceiving or their male partners. Exclusion criteria include participants with BMI < 18 kg/m2, animal trials, hereditary disorder in one or both partners and trials focusing solely on alcohol or smoking cessation/reduction, micronutrient supplementation, or diabetes control. Anthropometric, fertility, obstetric and fetal outcomes were assessed. Bias and quality assessments were performed.

MAIN RESULTS AND THE ROLE OF CHANCE

The search returned 1802 articles and eight studies were included for analysis. Populations targeted were primarily overweight or obese subfertile women seeking reproductive assistance, with few community-based studies and none including men. MA showed greater reduction in weight (n = 3, P < 0.00001, mean difference: -3.48 kg, 95% CI: -4.29, -2.67, I2 = 0%) and BMI (n = 2, P < 0.00001, mean difference: -1.40 kg/m2, 95% CI: -1.95, -0.84, I2 = 24%) with intervention. The only significant fertility outcome was an increased natural pregnancy rate (n = 2, P = 0.003, odds ratio: 1.87, CI: 1.24, 2.81, I2 = 0%). No differences were observed for ART adverse events, clinical pregnancy, pregnancy complications, delivery complications, live birth, premature birth, birth weight, neonatal mortality or anxiety. Risk of bias were high for three studies, moderate for three studies and low for two studies, Attrition bias was moderate or high in majority of studies.

LIMITATIONS, REASONS FOR CAUTION

Results were limited to subfertile or infertile women who were overweight or obese undergoing ART with no studies in men. The heterogeneous nature of the interventions in terms of duration and regimen means no conclusions could be made regarding the method or components of optimal lifestyle intervention. Attrition bias itself is an important factor that could affect efficacy of interventions.

WIDER IMPLICATIONS OF THE FINDINGS

Existing preconception lifestyle interventions primarily targeted overweight and obese subfertile women undergoing ART with a focus on weight loss. It is important to note that natural conception increased with lifestyle intervention. This emphasizes the need for further research exploring optimal components of preconception lifestyle interventions in the broader population and on the optimal nature, intensity and timing of interventions.

STUDY FUNDING/COMPETING INTEREST(S)

No conflict of interest declared. C.L.H. is a National Heart Foundation Postdoctoral Research Fellow. B.H. is funded by an Alfred Deakin Postdoctoral Research Fellowship. H.J.T. and B.W.M. hold NHMRC Practitioner fellowships. L.J.M. is supported by a SACVRDP Fellowship; a program collaboratively funded by the NHF, the South Australian Department of Health and the South Australian Health and Medical Research Institute.

PROSPERO REGISTRATION NUMBER

CRD42015023952.

Is parity a risk factor for excessive weight gain during pregnancy and postpartum weight retention? A systematic review and meta-analysis

The aim of this study was to systematically review and meta-analyse the associations between parity, pre-pregnancy body mass index (BMI), gestational weight gain (GWG) and, when included, postpartum weight retention (PPWR). Papers reporting associations between parity and BMI and/or GWG in adult women were eligible: 2,195 papers were identified, and 41 longitudinal studies were included in the narrative synthesis; 17 studies were included in a meta-analysis. Findings indicated that parity was associated positively with pre-pregnancy BMI. In contrast, the role of parity in GWG was less clear; both positive and negative relationships were reported across studies. Parity was not associated directly with PPWR. This pattern of results was supported by our meta-analysis with the only significant association between parity and pre-pregnancy BMI. Overall, parity was associated with higher pre-pregnancy BMI; however, the role of parity in GWG and PPWR remains unclear, and it is likely that its influence is indirect and complex. Further research to better understand the contribution of parity to maternal obesity is warranted.

Interventions to improve physical activity during pregnancy: a systematic review on issues of internal and external validity using the RE-AIM framework

BACKGROUND

Physical activity (PA) during pregnancy has significant health benefits for the mother and her child; however, many women reduce their activity levels during pregnancy and most are not sufficiently active. Given the important health benefits of PA during pregnancy, evidence that supports research translation is vital.

OBJECTIVES

To determine the extent to which physical activity interventions for pregnant women report on internal and external validity factors using the RE-AIM framework (reach, efficacy/effectiveness, adoption, implementation, and maintenance).

SEARCH STRATEGY

Ten databases were searched up to 1 June 2015. Eligible published papers and unpublished/grey literature were identified using relevant search terms.

SELECTION CRITERIA

Studies had to report on physical activity interventions during pregnancy, including measures of physical activity during pregnancy at baseline and at least one point post-intervention. Randomised controlled trials and quasi-experimental studies that had a comparator group were included.

DATA COLLECTION AND ANALYSIS

Reporting of RE-AIM dimensions were summarised and synthesised across studies.

MAIN RESULTS

The reach (72.1%) and efficacy/effectiveness (71.8%) dimensions were commonly reported; however, the implementation (28.9%) and adoption (23.2%) dimensions were less commonly reported and no studies reported on maintenance.

CONCLUSIONS

This review highlights the under-reporting of issues of contextual factors in studies of physical activity during pregnancy. The translation of physical activity interventions during pregnancy could be improved through reporting of representativeness of participants, clearer reporting of outcomes, more detail on the setting and staff who deliver interventions, costing of interventions and the inclusion of process evaluations and qualitative data.

TWEETABLE ABSTRACT

The systematic review highlights the under-reporting of contextual factors in studies of physical activity during pregnancy.

Characteristics of Four Upward-Pointing Cosmic-Ray-like Events Observed with ANITA

We report on four radio-detected cosmic-ray (CR) or CR-like events observed with the Antarctic Impulsive Transient Antenna (ANITA), a NASA-sponsored long-duration balloon payload. Two of the four were previously identified as stratospheric CR air showers during the ANITA-I flight. A third stratospheric CR was detected during the ANITA-II flight. Here, we report on characteristics of these three unusual CR events, which develop nearly horizontally, 20-30 km above the surface of Earth. In addition, we report on a fourth steeply upward-pointing ANITA-I CR-like radio event which has characteristics consistent with a primary that emerged from the surface of the ice. This suggests a possible τ-lepton decay as the origin of this event, but such an interpretation would require significant suppression of the standard model τ-neutrino cross section.

A parent-based intervention to promote healthy eating and active behaviours in pre-school children: evaluation of the MEND 2-4 randomized controlled trial

BACKGROUND

There is a paucity of studies evaluating targeted obesity prevention interventions in pre-school children.

OBJECTIVES

We conducted a randomized controlled trial to evaluate the efficacy of a parent-based obesity prevention intervention for pre-schoolers - MEND (Mind, Exercise, Nutrition … Do It!) 2-4 on child diet, eating habits, physical activity/sedentary behaviours, and body mass index (BMI).

METHODS

Parent-child dyads attended 10 weekly 90-min workshops relating to nutrition, physical activity and behaviours, including guided active play and healthy snack time. Assessments were conducted at baseline, immediately post-intervention, and 6 and 12 months post-intervention; child intake of vegetables, fruit, beverages, processed snack foods, fussiness, satiety responsiveness, physical activity, sedentary behaviour and neophobia were assessed via parent proxy report. Parent and child height and weight were measured.

RESULTS

Two hundred one parent-child dyads were randomized to intervention (n = 104) and control (n = 97). Baseline mean child age was 2.7 (standard deviation [SD] 0.6) years, and child BMI-for-age z-score (World Health Organization) was 0.66 (SD 0.88). We found significant positive group effects for vegetable (P = 0.01) and snack food (P = 0.03) intake, and satiety responsiveness (P = 0.047) immediately post-intervention. At 12 months follow-up, intervention children exhibited less neophobia (P = 0.03) than controls.

CONCLUSION

Future research should focus on additional strategies to support parents to continue positive behaviour change. ACTRN12610000200088.

A new apparatus design for high temperature (up to 950°C) quasi-elastic neutron scattering in a controlled gaseous environment

A design for a sample cell system suitable for high temperature Quasi-Elastic Neutron Scattering (QENS) experiments is presented. The apparatus was developed at the Spallation Neutron Source in Oak Ridge National Lab where it is currently in use. The design provides a special sample cell environment under controlled humid or dry gas flow over a wide range of temperature up to 950 °C. Using such a cell, chemical, dynamical, and physical changes can be studied in situ under various operating conditions. While the cell combined with portable automated gas environment system is especially useful for in situ studies of microscopic dynamics under operational conditions that are similar to those of solid oxide fuel cells, it can additionally be used to study a wide variety of materials, such as high temperature proton conductors. The cell can also be used in many different neutron experiments when a suitable sample holder material is selected. The sample cell system has recently been used to reveal fast dynamic processes in quasi-elastic neutron scattering experiments, which standard probes (such as electrochemical impedance spectroscopy) could not detect. In this work, we outline the design of the sample cell system and present results demonstrating its abilities in high temperature QENS experiments.