Women with specific health conditions (e.g., diabetes, inflammatory bowel disease, irritable bowel syndrome, coeliac disease, cystic fibrosis) require dietary adjustments that have been shown to reduce the risk of miscarriage

Introduction 

Pregnancy is a time of increased metabolic demand.1 Although individual energy and nutrient requirements vary between different women, a balanced diet to maintain a healthy body weight is essential to fetal development and maternal wellbeing. Furthermore, women with specific health conditions (e.g., diabetes, inflammatory bowel disease, irritable bowel syndrome, coeliac disease, cystic fibrosis) require dietary adjustments that have been shown to reduce the risk of miscarriage.2 

 

While there is a scarcity of evidence on the impact of diet specifically upon recurrent pregnancy loss (RPL), the negative effect of different nutritional imbalances on miscarriage is well documented.1,3 In addition, a very low or high body mass index (BMI) can be equally disadvantageous to gestating mothers and their babies.5 In women with anorexia nervosa, bulimia nervosa and binge eating disorder, the risk of sporadic miscarriage has been found to be threefold, although there is no clear association between a low BMI (<18.5 kg/m2) and RPL.3,5 Obesity, on the other hand, has been specifically linked to an increased risk of RPL (odds ratio [OR] 1.75, 95% confidence interval [CI] 1.24 to 2.47).4,5  

 

Other factors, including ethnicity, play an important role in the evaluation of body weight. For example, in the Caucasian population the evidence shows that reproductive outcomes are worse in those whose BMI is ≥30 kg/m2, whereas in people of Asian origin keeping a BMI lower than 27 kg/m2 should be encouraged.5 

 

In women with a BMI >40 kg/m2 in isolation, or >35 kg/m2 in the presence of comorbidities, the National Institute for Health and Care Excellence recommends bariatric surgery. After bariatric surgery women are at a higher risk of nutritional deficiencies including iron, folate, vitamin B12, fat-soluble vitamins and proteins.6 In turn, this increases the prevalence of small-for-gestational-age babies, preterm birth and maternal anaemia.7 

Bullet point guidance 

  • Pregnant women in the first trimester, and those trying to conceive, should be advised that a balanced diet, rich in fruit and vegetables, is crucial to maintaining a stable body weight and supporting embryo/fetal
  • Women and men with RPL should strive for a healthy BMI (19-25 kg/m2).5 
  • Clinicians should inform women and men trying to conceive that in the absence of known nutrient deficiencies, maintaining a healthy diet is the single most important intervention to ensure intake of the necessary amount of fibre, iron, iodine, calcium, zinc and most other micronutrients.1
  • Women who have had bariatric surgery should avoid conceiving within 12 months after surgery. A referral to obstetric medicine for preconception advice should be arranged.
  • The following supplementation doses of vitamin D should be considered:
  • 400 IU once daily for all pregnant women;
  • 1000 IU once daily for women at high risk of vitamin D deficiency (i.e., increased skin pigmentation, reduced exposure to sunlight, BMI³30 kg/m2 and socially excluded women).8
  • Folic acid at a dose of 5 mg once daily should be considered in women with any of the following features: BMI³30 kg/m2; epilepsy; diabetes types 1 and 2; sulfasalazine therapy for IBD; neural tube defect in a previous pregnancy; and sickle cell disease.9
  • The Eatwell Guide provides specific advice to achieve a healthy and balanced diet. This can be found online: https://www.gov.uk/government/publications/the-eatwell-guide
  • Clinicians should signpost women and men trying to conceive to the NHS Live Well website for information on exercise. This can be found here: https://www.nhs.uk/live-well/exercise/
  • The Tommy’s website contains useful information about exercise in pregnancy: https://www.tommys.org/pregnancy-information/im-pregnant/being-healthy/exercise

References 

  1. Mousa, A., A. Naqash, and S. Lim, Macronutrient and Micronutrient Intake during Pregnancy: An Overview of Recent Evidence. Nutrients 2019. 11(2): p. 443.
  2. Tursi, A., et al., Effect of gluten-free diet on pregnancy outcome in celiac disease patients with recurrent miscarriages. Digestive Diseases and Sciences 2008. 53(11): p. 2925-8.
  3. Charbonneau, K.D. and J.A. Seabrook, Adverse Birth Outcomes Associated with Types of Eating Disorders: A Review. Canadian Journal of Dietetic Practice and Research 2019. 80(3): p. 131-136.
  4. Cavalcante, M.B., et al., Obesity and recurrent miscarriage: A systematic review and meta-analysis. Journal of Obstetrics and Gynaecology Research 2019. 45(1): p. 30-38.
  5. Bender Atik, R., et al., ESHRE guideline: recurrent pregnancy loss. Human Reproduction Open 2018. 2018(2): p. hoy004.
  6. National Institiute for Health and Care Excellence. Obesity: Identification, Assessment and Management. CG189. NICE; 2014.
  7. Ibiebele I, Gallimore F, Schnitzler M, Torvaldsen S, Ford JB. Perinatal outcomes following bariatric surgery between a first and second pregnancy: a population data linkage study. BJOG 2020;127:345–54.
  8. RCOG, Vitamin D in Pregnancy – Scientific Impact Paper No. 43. 2014.
  9. Kennedy, D. and G. Koren, Identifying women who might benefit from higher doses of folic acid in pregnancy. Canadian family physician Medecin de famille canadien 2012. 58(4): p. 394-397.