Developing a tool for obtaining maternal skinfold thickness measurements and assessing inter-observer variability among pregnant women who are overweight and obese

Extent: 6p.Background: It is estimated that between 34% and 50% of Australian women entering pregnancy are overweight and obese, which is associated with an increased risk in complications for both the woman and her infant. Current tools used in clinical and research practice for measuring body composition include body mass index (BMI), waist circumference and bioimpedance analysis. Not all of these measures are applicable for use during pregnancy due to a lack of differentiation between maternal and fetal contributions. While skinfold thickness measurement (SFTM) is increasingly being used in pregnancy, there is limited data and a lack of a standard tool for its use in overweight and obese pregnant women. Methods: We developed a standard tool for evaluating SFTM among women with a BMI ≥ 25 kg/m2. Forty-nine women were measured as part of a prospective cohort study nested within a multicentre randomised controlled trial (The LIMIT Randomised Controlled Trial). Two blinded observers each performed 2 skinfold measurements on the biceps, triceps and subscapular of each woman. Intraclass correlation coefficients (ICC) and standard error of measurement (SEM) were used to analyse SFTM, body fat percentage (BF%) and inter-observer variability. Results: The ICC for inter-observer variability in measurements were considered moderate for biceps SFTM (ICC = 0.56) and triceps SFTM (ICC = 0.51); good for subscapular SFTM (ICC = 0.71) and BF% (ICC = 0.74); and excellent for arm circumference (ICC = 0.97). The standard error of measurements ranged from 0.53 cm for arm circumference to 3.58 mm for the subscapular SFTM. Conclusion: Our findings indicate that arm circumference and biceps, triceps and subscapular SFTM can be reliably obtained from overweight and obese pregnant women to calculate BF%, using multiple observers, and can be used in a research setting.Lavern M Kannieappan, Andrea R Deussen, Rosalie M Grivell, Lisa Yelland and Jodie M Dod

On the reliability of inflaton potential reconstruction

If primordial scalar and tensor perturbation spectra can be inferred from observations of the cosmic background radiation and large-scale structure, then one might hope to reconstruct a unique single-field inflaton potential capable of generating the observed spectra. In this paper we examine conditions under which such a potential can be reliably reconstructed. For it to be possible at all, the spectra must be well fit by a Taylor series expansion. A complete reconstruction requires a statistically-significant tensor mode to be measured in the microwave background. We find that the observational uncertainties dominate the theoretical error from use of the slow-roll approximation, and conclude that the reconstruction procedure will never insidiously lead to an irrelevant potential.Comment: 16 page LaTeX file with eight postscript figures embedded with epsf; no special macros neede

Use of intravenous iron polymaltose in the management of iron deficiency in pregnancy: a retrospective cohort study

Background: Intravenous iron polymaltose (IPM) is commonly utilised in pregnancy when oral treatment is not tolerated or where rapid replenishment of iron stores is required, but data on use in pregnancy is scarce. Aim: To examine the use, safety and efficacy of intravenous IPM in pregnancy. Methods: Retrospective cohort study of pregnant women administered intravenous IPM between January 2014 and January 2016 at a Tertiary teaching hospital in Adelaide, Australia. Data on maternal characteristics, intravenous iron infusion details, and haematological parameters were collected from case notes and electronic records. Main outcome measures included indication for intravenous iron infusion, prevalence of infusion reactions, change in haemoglobin and correction of anaemia prior to delivery. Results: Intravenous IPM was administered in 213 pregnancies, 62.0% of women with iron deficiency anaemia (IDA) and the remainder (38.0%) with non-anaemic iron deficiency. Adverse drug reactions (ADRs) occurred in 24% of women, of which 32% required infusion cessation. Anaemia was still present at delivery among 7%, and 17% of women with mild, and moderate/severe anaemia respectively. Approximately one in five anaemic women received an intravenous IPM dose below that recommended by the local guideline, particularly in women with a body mass index ≥ 25 kg/m² compared with <25 kg/m² (30.9% vs 6.3%; P < 0.001). Doses ‘at recommended’ resulted in a greater increase in haemoglobin from treatment until delivery than doses ‘below recommended’ (adjusted beta coefficient 8.4 g/L; 95% CI 2.7–14.1 g/L). Conclusion: Intravenous IPM is effective in treating IDA in pregnancy but is associated with a high prevalence of ADRs and treatment cessation.Alaa Qassim, Rosina G. Gergis, Bill Jeffries, Rosalie M. Grivell and Luke E. Grzeskowia

Paternal obesity modifies the effect of an antenatal lifestyle intervention in women who are overweight or obese on newborn anthropometry

The contribution of paternal obesity to pregnancy outcomes has been little described. Our aims were to determine whether the effect of an antenatal maternal dietary and lifestyle intervention among women who are overweight or obese on newborn adiposity, was modified by paternal obesity. We conducted a secondary analysis of a multicenter randomised trial. Pregnant women with BMI ≥25 kg/m2 received either Lifestyle Advice or Standard Care. Paternal anthropometric measures included height, weight, BMI; waist, hip, calf and mid-upper arm circumferences; biceps and calf skinfold thickness measurements (SFTM); and percentage body fat. Newborn anthropometric outcomes included length; weight; head, arm, abdominal, and chest circumferences; biceps, triceps, subscapular, suprailiac, thigh, and lateral abdominal wall SFTM; and percentage body fat. The effect of an antenatal maternal dietary and lifestyle intervention among women who were overweight or obese on neonatal anthropometric measures, was significantly modified by paternal BMI ≥35.0 kg/m2, with a significantly smaller infant triceps, suprailiac, and thigh SFTM, and percent fat mass, compared with that observed in offspring of lean fathers. Further research is required to determine whether our observed associations are causal, and whether paternal weight loss prior to conception is a potential strategy to reduce the intergenerational effects of obesity.Jodie M. Dodd, Lodewyk E. Du Plessis, Andrea R. Deussen, Rosalie M. Grivell, Lisa N. Yelland, Jennie Louise, Andrew J. Mcphee, Jeffrey S. Robinson and Julie A. Owen

The effect of an antenatal lifestyle intervention in overweight and obese women on circulating cardiometabolic and inflammatory biomarkers: secondary analyses from the LIMIT randomised trial

Background: Maternal overweight and obesity during pregnancy is associated with insulin resistance, hyperglycaemia, hyperlipidaemia and a low-grade state of chronic inflammation. The aim of this pre-specified analysis of secondary outcome measures was to evaluate the effect of providing antenatal dietary and lifestyle advice on cardiometabolic and inflammatory biomarkers. Methods: We conducted a multicentre trial in which pregnant women who were overweight or obese were randomised to receive either Lifestyle Advice or Standard Care. We report a range of pre-specified secondary maternal and newborn cardiometabolic and inflammatory biomarker outcomes. Maternal whole venous blood was collected at trial entry (mean 14 weeks gestation; non-fasting), at 28 weeks gestation (fasting), and at 36 weeks gestation (non-fasting). Cord blood was collected after birth and prior to the delivery of the placenta. A range of cardiometabolic and inflammatory markers were analysed (total cholesterol, triglycerides, non-esterified fatty acids, high-density lipoprotein cholesterol, insulin, glucose, leptin, adiponectin, C-reactive protein, granulocyte macrophage-colony stimulating factor, interferon gamma, TNF-α, and interleukins 1β, 2, 4, 5, 6, 8, and 10). Participants were analysed in the groups to which they were randomised, and were included in the analyses if they had a measure at any time point. results: One or more biological specimens were available from 1951 women (989 Lifestyle Advice and 962 Standard Care), with cord blood from 1174 infants (596 Lifestyle Advice and 578 Standard Care). There were no statistically significant differences in mean cardiometabolic and inflammatory marker concentrations across pregnancy and in infant cord blood between treatment groups. Estimated treatment group differences were close to zero, with 95% confidence intervals spanning a range of differences that were short of clinical relevance. There was no evidence to suggest that the intervention effect was modified by maternal BMI category. Conclusions: Despite our findings, it will be worth considering potential relationships between cardiometabolic and inflammatory markers and clinical outcomes, including longer-term infant health and adiposity. Trial Registration: Australian and New Zealand Clinical Trials Registry ( ACTRN12607000161426 ; Date Registered 09/03/2007).Lisa J. Moran, Louise M. Fraser, Tulika Sundernathan, Andrea R. Deussen, Jennie Louise, Lisa N. Yelland, Rosalie M. Grivell, Anne Macpherson, Matthew W. Gillman, Jeffrey S. Robinson, Julie A. Owens and Jodie M. Dod

Use of a DVD to provide dietary and lifestyle information to pregnant women who are overweight or obese: a nested randomised trial

Background: We conducted a nested randomised trial to evaluate the effect of an educational DVD, providing information about healthy food choices and exercise during pregnancy, on diet and physical activity, among pregnant women who were overweight or obese. Methods: We conducted a nested randomised trial within the context of the LIMIT randomised trial. Women were eligible with a singleton pregnancy between 10 and 20 weeks gestation, and body mass index at the time of their first antenatal appointment of ≥25 kg/m2. All women who were randomised to the Lifestyle Advice Group of the LIMIT trial received a series of consultations with both research dieticians and research assistants, in addition to standard written dietary and exercise materials (Standard Materials Group). Women randomised to the DVD Group received the same consultations and written materials, and additionally received an educational DVD (DVD Group). The primary study outcome was the Healthy Eating Index. Other study outcomes included physical activity, and gestational weight gain. Women completed a qualitative evaluation of all the materials provided. Results: 1,108 women in the LIMIT Lifestyle Advice Group participated in the nested trial, with 543 women randomised to the DVD Group, and 565 women to the Standard Materials Group. Women who received the DVD compared with those who did not, had a higher mean Healthy Eating Index at 36 weeks gestation (73.6 vs 72.3; adjusted mean difference 1.2; 95% CI 0.2 to 2.3; p = 0.02), but not at 28 weeks gestation (73.2 vs 73.5; adjusted mean difference −0.1; 95% CI −1.1 to 0.9; p = 0.82). There were no statistically significant differences in physical activity or total gestational weight gain. While most women evaluated the materials positively, frequency of utilisation was poor. Conclusions: Ongoing attention to the delivery of information is required, particularly with the increased use and availability of digital and multi-media interactive technologies.Malgorzata A Szmeja, Courtney Cramp, Rosalie M Grivell, Andrea R Deussen, Lisa N Yelland and Jodie M Dod

Effect of metformin in addition to dietary and lifestyle advice for pregnant women who are overweight or obese: the GRoW randomised, double-blind, placebo-controlled trial

BACKGROUND:Maternal overweight and obesity are associated with well recognised pregnancy complications. Antenatal dietary and lifestyle interventions have a modest effect on gestational weight gain without affecting pregnancy outcomes. We aimed to assess the effects on maternal and infant outcomes of antenatal metformin given in addition to dietary and lifestyle advice among overweight and obese pregnant women. METHODS:GRoW was a multicentre, randomised, double-blind, placebo-controlled trial in which pregnant women at 10-20 weeks' gestation with a BMI of 25 kg/m2 or higher were recruited from three public maternity units in Adelaide, SA, Australia. Women were randomly assigned (1:1) via a computer-generated schedule to receive either metformin (to a maximum dose of 2000 mg per day) or matching placebo. Participants, their antenatal care providers, and research staff (including outcome assessors) were masked to treatment allocation. All women received an antenatal dietary and lifestyle intervention. The primary outcome was the proportion of infants with birthweight greater than 4000 g. Secondary outcomes included measures of maternal weight gain, maternal diet and physical activity, maternal pregnancy and birth outcomes, maternal quality of life and emotional wellbeing, and infant birth outcomes. Outcomes were analysed on an intention-to-treat basis (including all randomly assigned women who did not withdraw consent to use their data, and who did not have a miscarriage or termination of pregnancy before 20 weeks' gestation, or a stillbirth). The trial is registered with the Australian New Zealand Clinical Trials Registry, number ACTRN12612001277831. FINDINGS:Of 524 women who were randomly assigned between May, 28 2013 and April 26, 2016, 514 were included in outcome analyses (256 in the metformin group and 258 in the placebo group). Median gestational age at trial entry was 16·29 weeks (IQR 14·43-18·00) and median BMI was 32·32 kg/m2 (28·90-37·10); 167 (32%) participants were overweight and 347 (68%) were obese. There was no significant difference in the proportion of infants with birthweight greater than 4000 g (40 [16%] with metformin vs 37 [14%] with placebo; adjusted risk ratio [aRR] 0·97, 95% CI 0·65 to 1·47; p=0·899). Women receiving metformin had lower average weekly gestational weight gain (adjusted mean difference -0·08 kg, 95% CI -0·14 to -0·02; p=0·007) and were more likely to have gestational weight gain below recommendations (aRR 1·46, 95% CI 1·10 to 1·94; p=0·008). Total gestational weight gain, pregnancy and birth outcomes, maternal diet and physical activity, and maternal quality of life and emotional wellbeing did not differ significantly between groups. Similar numbers of women in both treatment groups (76% [159/208] in the metformin group and 73% [144/196] in the placebo group) reported side-effects including nausea, diarrhoea, and vomiting. Two stillbirths (placebo group) and one neonatal death (metformin group) occurred; none of the perinatal deaths were determined to be attributable to participation in the trial. INTERPRETATION:For pregnant women who are overweight or obese, metformin given in addition to dietary and lifestyle advice initiated at 10-20 weeks' gestation does not improve pregnancy and birth outcomes. FUNDING:Australian National Health and Medical Research Council.Jodie M Dodd, Jennie Louise, Andrea R Deussen, Rosalie M Grivell, Gustaaf Dekker, Andrew J McPhee and William Hagu

Accurate determination of inflationary perturbations

We use a numerical code for accurate computation of the amplitude of linear density perturbations and gravitational waves generated by single-field inflation models to study the accuracy of existing analytic results based on the slow-roll approximation. We use our code to calculate the coefficient of an expansion about the exact analytic result for power-law inflation; this generates a fitting function which can be applied to all inflationary models to obtain extremely accurate results. In the appropriate limit our results confirm the Stewart--Lyth analytic second-order calculation, and we find that their results are very accurate for inflationary models favoured by current observational constraints.Comment: 9 pages LaTeX file with 3 figures incorporated, using RevTeX and eps