Page 58 - Retail Pharmacy Magazine October 2020

56 CPD ACTIVITY MATERNAL WEIGHT: IMPACT ON PREGNANCY AND BEYOND Dr Treasure McGuire Treasure is Assistant Director of Pharmacy, Mater Health Services, South Brisbane, a Conjoint Lecturer, School of Pharmacy, University of Queensland, and Associate Professor of Pharmacology, Faculty of Health, Sciences & Medicine, Bond University. LEARNING OBJECTIVES After completing this CPD activity, pharmacists should be able to: • Describe the physiological role of weight gain in pregnancy. • Describe the health implications of abnormal weight changes in pregnancy. • Provide evidence-based advice to support women to maintain a healthy weight gain in pregnancy and a healthy weight loss post-partum. 2016 Competency Standards: 2.1, 2.3, 3.1, 3.2, 3.3. Accreditation Number: A2010RP1 (Exp: 30/09/2022). Introduction Women’s weight status, body image and eating patterns are affected by issues related to their reproductive health, during preconception, pregnancy and postpartum. Abnormal weight gain or weight loss can impact on all areas of medicine, with obesity one of the most challenging global public health issues.1 In obstetrics, excessive gestational weight gain (GWG), preconception obesity or postpartum weight retention impact on both maternal and neonatal health.1,2 Recent studies also demonstrate the influence of maternal nutrition and abnormal weight changes on the prevalence of obesity in subsequent generations (epigenetics).2-4 For many primary healthcare professionals, pregnancy and postpartum represent an opportunity to break the epigenetic cycle and reduce the susceptibility of offspring to a wide range of non- communicable diseases in later life, including allergic, metabolic, psychiatric and neurodegenerative disorders. This review outlines why a healthy pregnancy requires controlled weight gain but how fixation on body image can place undue pressure on new mothers to achieve rapid weight loss. Strategies for healthy postpartum weight loss are discussed. Why do pregnant women gain weight? Physiological weight gain is essential for a healthy pregnancy. The foetus requires an uninterrupted source of glucose and amino acids for growth. Amino acid uptake is increased after meals, but amino acid release is reduced during fasting, causing a net conservation of maternal lean tissue. Modifications to fat utilisation occur between meals to provide for maternal energy needs while conserving glucose and amino acids for foetal fuel and synthesis of maternal and foetal lean tissue. The placenta produces hormones that promote greater use of lipids as a maternal energy source. This may increase glucose and amino acid availability for foetal use. The net effects of the hormonal changes during pregnancy are a reduced energy cost for the synthesis of fat or protein, increased propensity to store excess energy as maternal fat after meals and to mobilise these energy-dense stores in the fasted state.5 GWG differs widely among healthy women delivering single, full-term infants, due to differences in maternal characteristics such as: 5,6 • Pre-pregnancy weight-for-height status. • Age. • Parity. • Ethnic origin. • Socioeconomic status. • Substance abuse. • Physical activity level. Population-based studies have demonstrated that weight gain in pregnant women is inversely related to maternal pre-conception body mass index (BMI).7 For singleton gestations, physiological changes include:6 • 40–50 per cent increase in plasma volume and amniotic fluid (≈8kg over the life of the pregnancy). • 30-50 per cent increase in cardiac output due to increases in stroke volume and maternal heart rate. • 20 per cent decrease in systemic vascular resistance as early as five weeks. • 40–60 per cent decrease in maternal insulin sensitivity, increasing glucose availability to the foetus, depending on preconception metabolic status.8 • One extra kg of protein (as maternal, placental, and foetal lean mass) in addition to variable amounts (between 1kg and 6kg) of adipose tissue to meet RETAIL PHARMACY • OCT 2020 2 CPD CREDITS