Can a pre-conception weight loss program improve maternal and infant outcomes for women with overweight or obesity? A pragmatic randomised controlled trial (RCT).
The University of Sydney
1,927 participants
Dec 8, 2021
Interventional
Conditions
Summary
Almost half of women who become pregnant have overweight or obesity. As well as increasing the mother’s health risks, their babies have a higher risk of stillbirth, preterm birth, delivery complications due to larger size plus are more likely to develop childhood and adult obesity. Whilst trials to limit weight gain during pregnancy have had very limited success, there is increasing recognition that targeting obesity prior to pregnancy has greater potential to break the obesity cycle. Yet a recent Cochrane review of targeted pre-conception interventions in women with overweight or obesity found no eligible trials. If pre-conception weight loss in women with overweight or obesity were to be effective and translatable at scale, it would have enormous potential to improve the wellbeing of mothers as well as their babies in both the short and longer term. Aim: To evaluate the effectiveness of a translatable meal replacement diet program for women with overweight or obesity planning pregnancy on the incidence of significant perinatal outcomes compared with recommended advice. Design: A superiority, unblinded, multicenter RCT with two parallel groups and primary endpoint of combined perinatal adverse outcome. Population: Women (18-40 years) with overweight or obesity (BMI greater than 25kg/m2) planning a pregnancy within 6-12 months and intending to deliver at a recruiting centre. Methods: A pragmatic randomised controlled trial conducted across public maternity hospitals in New South Wales. We will recruit 1927 women with a BMI greater than 25 kg/m2. They will be randomised to: a) Nutritionally complete meal replacement diet program or b) recommended preconception advice on weight management, for a 10- week period with a 12 month follow up schedule. Outcomes Primary: gestational diabetes mellitus; pre-eclampsia; first Caesarean section, perinatal death; LGA (birth weight greater than 90th centile); admission to a neonatal unit. Secondary: Separate components of the composite outcome plus the following: Perinatal: Stillbirth (infant loss greater than 20 weeks of gestation), neonatal death, need for resuscitation at delivery, shoulder dystocia, nerve palsy, fracture, birthweight, breastfeeding at discharge Obstetric and Maternal: Gestational hypertension, assisted vaginal birth, spontaneous vaginal birth, post-partum haemorrhage, 3rd and 4th degree tears, length of stay in hospital,
Eligibility
Inclusion Criteria6
- – Women with a BMI greater than or equal to 25kg/m2
- Planning a pregnancy within 6 to 12 months
- – Willing to attend 3 consults either in the clinic or via telehealth
- Provide pregnancy and birth details to the research team
- – Willing to follow a weight loss dietary protocol for 10 weeks
- – Has been weight stable (i.e. less than 3 kg weight loss) for the past 2 months.
Exclusion Criteria10
- – Significant pre-existing, diagnosed medical condition that may prevent them from participating in the study, including but not limited to: Kidney disease or renal impairment; Gall bladder disorders or stones; Liver disease (e.g. cirrhosis); severe cardiovascular disease where rapid weight loss is contraindicated eg Cardiac arrhythmia, congenital heart disease; Malabsorptive Gastrointestinal disease (including celiac, Crohns disease);
- – History of bariatric surgery;
- – Severe depression;
- – Cancer (unless benign or non-progressive skin cancer);
- – Type 1 diabetes and type 2 diabetes if on insulin.
- – Regular use of medications prescribed by a medical practitioner that are deemed unsuitable for this trial – as determined by the appointed study physician during screening process;
- – A food allergy/intolerance to, or not willing to consume, the foods prescribed in the protocol;
- Postpartum <6 months or currently breastfeeding;
- – A person considered by the investigator to be unwilling, unlikely or unable to comprehend or comply with the study protocol;
- A person unable to to provide informed consent
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Interventions
The aim of this trial is to determine whether a meal replacement diet program (Impromy) in women (18-40 years) with overweight or obesity (BMI greater than 25 kg/m2) who are planning a pregnancy in the next 6 to 12 months improves perinatal outcomes and is cost-effective compared to usual care. The intervention arm comprises an Australian meal replacement product (details available on the website https://cpc.impromy.com/) that will be delivered in 5 clinic /telehealth settings targeted for women planning pregnancy. All women will have a baseline (visit/consult 1), week 5 (visit/consult 2) and 10 week (visit/consult 3) appointment with a dietitian/midwife/researcher. The baseline and the 10 week appointments are 1 hour in duration and the 5 week appointment 30 minutes. Women randomised to the intervention arm will be advised to follow the Impromy program for 10 weeks and will be registered with the PreBabe/Impromy website and given instructions on the meal replacement diet and provided with meal replacements. The Impromy program is based on alternate day energy restriction (e.g. Tuesday, Thursday, and Sunday comprise meal replacements and one healthy meal with protein and Monday, Wednesday, and Friday meal replacements plus salad/vegetables) to allow for one day per week to eat ad libitum ( e.g. Saturday). A trained research dietitian or trained research officer/ midwife will deliver and monitor the dietary intervention. Individual estimated energy requirements will be calculated for all women at study visit 1 based on actual body weight, multiplied by appropriate physical activity levels and reduced by 25-30% to achieve energy restriction for weight loss. This individualised energy level determines the number of formulated meal replacements and the number of snacks for each woman. For example women with BMI 25 - 30 are likely to require 2 meal replacements per day and BMI > 30, 3 meal replacements per day. Meal replacements require reconstitution with 250 mL of either skim milk or a dairy-free alternative (unsweetened, calcium-enriched). The 10-week meal replacement diet program selected for this trial uses nutritionally complete meal replacement products. (Impromy meal replacements and supplied by Blackmores Ltd 20 Jubilee Avenue Warriewood 2102., Australia; MR =~1000kJ, 25g protein, 4g fat, 27g carbohydrate, 6g fibre with each containing 25% recommended daily intake for Vitamin A, Thiamin, Riboflavin, Niacin, Folate, Vitamin B6, Vitamin B12, Vitamin C, Vitamin D, Vitamin E, Calcium, Iodine, Iron, Magnesium, Phosphorus and Zinc.) The total daily macronutrient distribution for the MRP diet shown above was 31% of total energy as carbohydrate, 38% protein and 28% total fat (52% monounsaturated fat and 17% polyunsaturated fat) with the remaining 3% non-soluble fibre. Prescribed snack option for the plan include: fruit, low fat dairy, whole-grains and nut/seed/legume. The number of snacks allocated per day is also tailored to individual energy requirements for weight loss. Behavioural strategies included in the dietitian/research midwife visits and the accompanying website include, goal setting, self-monitoring of behaviour and progress, stimulus control (e.g. recognising triggers that prompt unplanned eating), cognitive restructuring (modifying unhelpful thoughts), problem solving, assertiveness, slowing the rate of eating, reinforcing changes and relapse prevention. We will also provide a helpline for the program so women are able to access a dietitian for advice during the 10 weeks. This support will be available via a dedicated email monitored by 3 study team members and a study mobile phone during business hours. The website provides general advice regarding the program and weight loss support plus a virtual consultation which has been informed through the FAQs of the CSIRO pilot trial and has been designed by dietitians Women will also receive a copy of the printed booklet from the Australian Government website regarding healthy weight. http://healthyweight.health.gov.au We will monitor adherence to the meal replacements by questionnaires, weight measurement at the study visit and a count of supplied products to the participating women.
Locations(6)
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ACTRN12620001238965