The Maternal Obesity Management (MOM) Trial: lifestyle intervention during pregnancy to minimize downstream obesity in mother and child - a Pilot Study

1. Gestational weight gain will be calculated by subtracting weight at the first prenatal visit in the first trimester from weight at her last prenatal visit before delivery. This will be logged as an absolute value. We will also record the average weekly weight gain to account for the variable length of the observation period (i.e., gestational age at recruitment and delivery).
2. Infant birth weight (grams) will be obtained from obstetrical records and recorded as a continuous variable in grams and further categorised as:
2.1. Small for gestational age (less than 10th percentile)
2.2. Normal for gestational age
2.3. Large for gestational age otherwise known as macrosomia (birth weight greater than 90th percentile), based on weeks gestation

1. GWG will be further categorised as gaining less than recommended, the recommended amount, or more than recommended according to the IOM gestational weight gain guidelines. For obese women, the upper limit of the recommended range will be set at 11.5 kg. Weight will also be measured at the end of each trimester over the course of the intervention to monitor the pattern of weight gain.
2. Data on other complications during pregnancy or delivery will be obtained as recorded at prenatal visits and from obstetrical records during delivery:
2.1. Gestational Diabetes (Yes or No) will be defined as an abnormal glucose tolerance test (2-hour 75 g glucose tolerance test [GTT] after fasting with sampling at 0 hours, 1 hour and 2 hours) following initial screening collected through prenatal obstetrical records
2.2. Pre-eclampsia (Yes or No) will be defined as: systolic blood pressure greater than 140 mm Hg or diastolic greater than 90 mm Hg on at least two readings and/or the presence of HEELP syndrome (haemolysis, elevated liver enzymes, and lowered platelets)
2.3. Instrumental delivery collected through obstetrical records (vacuum, forceps etc.)
2.4. C-section collected through obstetrical records (yes or no, scheduled or emergent)
2.5. NICU admission collected through obstetrical records
2.6. Foetal distress collected through obstetrical records
2.7. Low APGAR (less than or equal to 3 at 5 minutes) scores collected through obstetrical records
3. Biomarkers: As it is exceptionally difficult, and in most cases not possible to actually measure the intrauterine environment in humans we will take blood samples, at study intake and at the end of each trimester, to measure biomarkers as surrogates of intrauterine environment. Foetal growth is largely determined by nutrient transfer across the placenta, which is dependent on maternal nutrient levels and placenta transport capacity. Hormones such as insulin, leptin, and insulin-like growth factor-1 (IGF-1) have been shown to stimulate nutrient transport. Earlier than expected changes in hormones associated with maternal metabolism or dietary intake in OW/OB pregnant women may have marked effects on foetal growth trajectory. We will measure markers related to glucose homeostasis, fat mass, nutrient transport, inflammation and stress since preliminary research has identified the role of these variables in pregnancy and outcomes related to obesity:
3.1. Glycosylated hemoglobin (HbA1c) reflects the mean concentration of blood glucose over the previous 2 - 3 months
3.2. Insulin resistance is estimated using the homeostatic model assessment (HOMA) formula, which calculates insulin resistance based on the fasting plasma glucose and insulin. The HOMA model is a structured model of the glucose-insulin feedback system in the homoestatic (overnight-fasted) state.
3.3. Insulin-like growth factor binding protein-1, which binds and modulates the activities of IGF-1 and IGF-2, is thought to upregulated placental nutrient transport. Serum levels are associated with birthweight and pre-eclampsia.
3.4. Cortisol is a hormone involved in glucose metabolism and appetite regulation but is also involved in the stress response
3.5. Leptin circulates at levels proportional to fat mass and provides input to the brain regarding energy storage so it can regulate appetite and metabolism and has been linked to placental nutrient transport
3.6. Adiponectin is produced by the adipocyte, is inversely related to fat mass, has anti-inflammatory properties and influences the body's response to insulin
3.7. C-reactive protein (CRP) is a marker of inflammation and elevated levels are common in diabetes and obesity. CRP level is a very strong independent CVD risk factor in women and if elevated during pregnancy is a predictor of increased atherogenesis in offspring. Research indicates that endurance training reduces CRP.
4. Physical activity level will be measured both directly and indirectly. Accelerometers will be used to collect objective, reliable and accurate measures of physical activity. The 7 Day Physical Activity Recall (7 Day-PAR), a valid self report measure of physical activity and sedentary behaviour in women will also be used to assess PA. This tool will be used to specify what type of activity participants are doing when they are active and how they are spending their time in sedentary behaviour in their natural environment.
5. Dietary habits: Resting energy expenditure (REE) will be measured in the HALO lab using indirect calorimetry (Ultima PF/PFX a metabolic system), to predict an individual's daily energy requirements. The determination of daily caloric need is fundamental in nutritional assessment and necessary for helping individuals attain and maintain a healthy body weight. Total calories consumed, calories from snacks and meals, and macronutrient composition (percent of calories from fats, carbohydrates and protein), will be assessed using 7-day food records at study intake and at the end of each trimester.
6. Psychosocial functioning: Although many psychosocial factors may play a role in gestational weight gain, the literature points to four being especially important: stress, social support, depression, and attitudes towards pregnancy. We will measure these variables at study intake and at the end of each trimester.
6.1. Pregnancy experience scale (PES): this 41-item scale measures pregnancy-specific daily hassles and provides the most balanced assessment of stress during pregnancy
6.2. Maternal Social Support Index (MSSI): this scale consists of 24 questions relating to patient's perceptions of daily task-sharing among household members, satisfaction with relationships, availability of emergency help, and degree of community involvement. Total scores range from 0 (low social support) to 19 (high social support).
6.3. The Edinburgh Postnatal Depression Scale (EPDS) is an effective 10 item screening tool used to identify patients at risk for 'perinatal' depression. Respondents are asked how they have been feeling the past 7 days. Items are assessed by scales ranging from "not at all or never" to "most of the time".
6.4. Pregnancy and Weight Gain Attitude Scale is comprised of 18 items, 15 about weight-related attitudes and 3 about behaviours during pregnancy. Responses for each statement range from "strongly disagree" to "strongly agree". Low scores represent a negative attitude toward weight gain in pregnancy, and high scores represent a positive attitude.
7. Post-partum: Maternal variables will measured at 3, 6, and 12 months post-delivery
7.1. Weight retention, calculated as measured weight at follow-up minus pregravid weight, will be measured during a home visit at 3 and 6 months and in the HALO lab at 1 year
7.2. Body composition: body fat, and lean body mass will be measured at the HALO lab at 1 year via DEXA. DEXA is rapidly becoming the clinical method of choice for direct calculation of total fat, lean and bone tissue because of its low radiation dose, speed, ease of application, and superior reproducibility over other non-invasive methods that estimate tissue characteristics. Precautions will be taken to ensure that women are not pregnant prior to undergoing the DEXA.
7.3. Dietary habits (see above)
7.4. Physical activity level (see above)
7.5. Infant feeding practices will be determined by asking the mothers about how long (in weeks) they had fully breastfed their child for, defined as breast milk only without any supplemental solid foods or liquids other than water. If the mother is still fully breastfeeding, this question is repeated at each subsequent visit (e.g, 6, 12 months) until complementary feeding is initiated.
8. Post-partum: offspring variables will be measured at 3, 6, and 12 and 24 months after birth:
8.1. Offspring height: Infants will be measured crown-heel in the recumbent position to the nearest 1 mm. Weight: infant weight will be measured using an electronic baby scale to the nearest 1 g (less than 3 kg), 2 g (3 - 6 kg), or 5 g (greater than 6 kg). Child growth trajectories and obesity over the 1st year will be calculated using the gender and age- specific (nearest 6 months of age as recommended) BMI cut off points recommended for use in international comparisons of prevalence of overweight and obesity.
8.2. Offspring body composition will be estimated from the sum of skin folds assessed in duplicate at 4 sites on the right side of the body at the biceps, triceps, subscapular, suprailiac to the nearest 0.1 mm with infant skin fold calipers
8.3. Physical activity (self-generated and spontaneous movement) will be measured by placing an activity monitor (Actiwatch®, Respironics/Mini Mitter), that records a digitally integrated measure of gross motor activity via accelerometry, on the right ankle using an ankle band and another Actiwatch® will be placed just above the iliac crest on the infants' right side using hypoallergenic medical tape to hold it in place along with a no alcohol liquid barrier to further decrease chance of irritation. The 24-h activity data will be analyzed to determine the separation of moderate-to-vigorous activity and sedentary-to-light activity, the classification of sleep and wake state for each data point, and the transition points from day to night and night to day.