Nutrition to support a healthy pregnancy

Optimising nutrition and lifestyle can reduce the risk of abnormalities occurring as well as protect against nutritional deficiencies both of which are essential for optimising fertility and pregnancy outcomes.

Ways nutrition can support a healthy pregnancy

Along with reducing risk of neural tube defects, taking a 400μg folic acid (vitamin b9) supplement every day prior to, and during the first 12 weeks of pregnancy can reduce risk of miscarriage(1)(2). In women undergoing assisted reproduction, optimal folate levels have been associated with more favourable pregnancy rates due to its advantageous effects onembryo morphology (3,4). Folate is the natural form of vitamin B9, folic acid on the other hand is the synthetic form and is converted to folate in the body. People who carry a genetic variant in the MTHFR gene may be unable to convert folic acid to folate leading to folic acid build-up increasing risk of miscarriage. Choosing supplements containing methylfolate rather than folic acid may therefore be preferable.

Data suggests that vitamin D deficiency is associated with both spontaneous and recurrent miscarriage (5). We can get small amounts of Vitamin D from food sources such as oily fish, eggs and fortified foods, but it is very difficult to reach our requirements through diet alone. During the summer months we are able to hit our vitamin D targets more easily due to sun exposure.However, due to low levels of sun exposure during the winter, coupled with time spent indoors and low levels of Vitamin D found in food, vitamin D deficiency is common in the UK. If you are pregnant or trying to conceive, it is recommended to take a 10μg supplement of vitamin D daily. Prenatal supplements often contain vitamin D so if this is the case it is unlikely you will need to take an additional vitamin D supplement.

Consuming a Mediterranean style diet, rich in vegetables, fruits, legumes, olive oil, oily fish, lean meat and wholegrains can aid fertility. Diets that deviate from this pattern such as those lower in green vegetables, fruit and dairy products and with a higher intake of fat have been shown to increase risk of spontaneous early miscarriage (7,8). The antioxidant properties of fruit and vegetables can help to protect sperm and eggs from DNA damage (6). Nuts, seeds, leafy green vegetables, whole grains, dairy and poultry also contain zinc and copper, optimum levels of which can also reduce the risk of spontaneous miscarriage (9). A diet deficient in selenium has been linked to miscarriage (13), selenium can be gained from some fortified cereals, seafood, lean meats, poultry, eggs, legumes, nuts and seeds all of which are recommended as part of a healthy diet.

Choline is important for placental function as well as early brain development helping to prevent neural tube defects (10). Prenatal vitamins don’t regularly contain choline (11) however it can be found in peanut butter, pinto beans, eggs, quinoa, tofu, broccoli and brussel sprouts. If these aren’t a regular component of your diet then an additional supplement may be worth considering.

Being overweight can increase chances of pregnancy complications with the overall chance of miscarriage in the first 12 weeks increasing from 20 to 25% when BMI goes over 30 (12). Optimising weight prior to pregnancy is recommended to reduce risk of complications for you and your baby.

Recently a study in mice suggested that vitamin B3 (niacin) supplementation could prevent a genetic cause of birth defects and miscarriage. While there is not currently enough research in humans to advocate supplementation, ensuring you are incorporating sources of this vitamin into your diet such ameat, poultry, tuna, salmon, cereals, legumes, and seeds, avocado, milk, green leafy vegetablesand yeast products, is definitely worthwhile (14).

Long term health conditions can increase risk of miscarriage in the second trimester, working with your doctor to ensure conditions such as diabetes and blood pressure are well controlled through diet or medication is especially important (15,16).

Foods to avoid

Caffeine consumption should be limited to 200mg/day, consumption over this amount, particularly at weeks 8–19, increases the risk of spontaneous abortion (18,19). Women are also recommended to abstain from alcohol, even immoderate intake can increase risk of loss (20).

When choosing seafood, avoid fish such as shark, swordfish and marlin as these can contain heavy metals such as mercury that have been linked to miscarriage (17). Pregnant women are recommended to include seafood in their diet twice per week. Oily fish such as salmon and sardines are great choices as they are rich in omega 3 fatty acids which are essential for foetal development. Shellfish are also a great source of selenium, zinc and copper. Seafood should always be cooked and not raw.

Mould ripened cheeses, pate, cured or rare meat all have the potential to contain listeria which is linked tomiscarriage and should be avoided. Unpasteurised dairy products as well as uncooked eggs also have the potential to contain harmful bacteria. British lion stamped eggs however can be eaten soft boiled or raw, if you are unsure where your eggs came from then they should be cooked through.

Miscarriage cannot always be prevented and in many cases causes are not always identified. Optimising your diet and lifestyle is one of the factors that is within your control and can help ensure that you are in the best possible position to enjoy a healthy pregnancy. If you have had 3 or more miscarriages in a row it is recommended to seek professional advice from your doctor to check for any underlying causes.

References

1. Mao Y-Y, Yang L, Li M, Liu J, Zhu Q-X, He Y, et al. Periconceptional Folic Acid Supplementation and the Risk of Spontaneous Abortion among Women Who Prepared to Conceive: Impact of Supplementation Initiation Timing. Nutrients [Internet]. 2020 Jul 29 [cited 2020 Aug 7];12(8):2264. Available from: https://www.mdpi.com/2072-6643/12/8/2264
2. Gaskins AJ, Rich-Edwards JW, Hauser R, Williams PL, Gillman MW, Ginsburg ES, et al. Maternal prepregnancyfolate intake and risk of spontaneous abortion and stillbirth. In: Obstetrics and Gynecology [Internet]. Lippincott Williams and Wilkins; 2014 [cited 2020 Aug 7]. p. 23–31. Available from: /pmc/articles/PMC4086728/?report=abstract
3. Thaler CJ. Folate metabolism and human reproduction. Geburtshilfe Frauenheilkd [Internet]. 2014 [cited 2020 Aug 21];74(9):845–51. Available from: /pmc/articles/PMC4175124/?report=abstract
4. Boxmeer JC, MacKlon NS, Lindemans J, Beckers NGM, Eijkemans MJC, Laven JSE, et al. IVF outcomes are associated with biomarkers of the homocysteine pathway in monofollicular fluid. Hum Reprod [Internet]. 2009 [cited 2020 Jul 14];24(5):1059–66. Available from: https://pubmed.ncbi.nlm.nih.gov/19221098/
5. Andersen LB, Jørgensen JS, Jensen TK, Dalgård C, Barington T, Nielsen J, et al. Vitamin D insufficiency is associated with increased risk of firsttrimester miscarriage in the Odense Child Cohort1-2. Am J Clin Nutr. 2015 Sep 1;102(3):633–8.
6. Gaskins AJ, Rich-Edwards JW, Hauser R, Williams PL, Gillman MW, Penzias A, et al. Prepregnancy dietary patterns and risk of pregnancy loss. Am J Clin Nutr [Internet]. 2014 Oct 1 [cited 2020 Aug 7];100(4):1166–72. Available from: /pmc/articles/PMC4163795/?report=abstract
7. Di Cintio E, Parazzini F, Chatenoud L, Surace M, Benzi G, Zanconato G, et al. Dietary factors and risk of spontaneous abortion. Eur J Obstet Gynecol Reprod Biol [Internet]. 2001 [cited 2020 Aug 7];95(1):132–6. Available from: https://pubmed.ncbi.nlm.nih.gov/11267735/
8. Maconochie N, Doyle P, Prior S, Simmons R. Risk factors for first trimester miscarriage -Results from a UK-population-based case-control study. BJOG An Int J Obstet Gynaecol [Internet]. 2007 Feb [cited 2020 Aug 7];114(2):170–86. Available from: https://pubmed.ncbi.nlm.nih.gov/17305901/
9. Thaker R, Oza H, Shaikh I, Kumar S. Correlation copper and zinc in spontaneous abortions? Int J Fertil Steril[Internet]. 2019 Jul 1 [cited 2020 Aug 7];13(2):97–101. Available from: /pmc/articles/PMC6500075/?report=abstract
10. Zeisel SH. The supply of choline is important for fetal progenitor cells [Internet]. Vol. 22, Seminars in Cell and Developmental Biology. Elsevier Ltd; 2011 [cited 2020 Jun 24]. p. 624–8. Available from: /pmc/articles/PMC3188336/?report=abstract
11. Bell CC, Aujla J. Prenatal Vitamins Deficient in Recommended Choline Intake for Preg-nant Women. J Fam Med Dis Prev [Internet]. 2016 [cited 2020 Jun 24];2:48. Available from: https://ndb.nal.usda.gov/ndb/nu-
12. Metwally M, Saravelos SH, Ledger WL, Li TC. Body mass index and risk of miscarriage in women with recurrent miscarriage. Fertil Steril [Internet]. 2010 Jun [cited 2020 Aug 7];94(1):290–5. Available from: https://pubmed.ncbi.nlm.nih.gov/19439294/
13. Pieczyńska J, Grajeta H. The role of selenium in human conception and pregnancy [Internet]. Vol. 29, Journal of Trace Elements in Medicine and Biology. Elsevier GmbH; 2015 [cited 2020 Aug 7]. p. 31–8. Available from: https://pubmed.ncbi.nlm.nih.gov/25175508/
14. Shi H, Enriquez A, Rapadas M, Martin EMMA, Wang R, Moreau J, et al. NAD Deficiency, Congenital Malformations, and Niacin Supplementation. N Engl J Med [Internet]. 2017 Aug 10 [cited 2020 Aug 7];377(6):544–52. Available from: http://www.nejm.org/doi/10.1056/NEJMoa1616361
15. Nobles CJ, Mendola P, Mumford SL, Naimi AI, Yeung EH, Kim K, et al. Preconception blood pressure levels and reproductive outcomes in a prospective cohort of women attempting pregnancy. Hypertension [Internet]. 2018 May 1 [cited 2020 Aug 21];71(5):904–10. Available from: /pmc/articles/PMC5897130/?report=abstract
16. Tian L, Shen H, Lu Q, Norman RJ, Wang J. Insulin Resistance Increases the Riskof Spontaneous Abortion after Assisted Reproduction Technology Treatment. J Clin Endocrinol Metab [Internet]. 2007 Apr 1 [cited 2020 Aug 21];92(4):1430–3. Available from: https://academic.oup.com/jcem/article/92/4/1430/2597532
17. Amadi CN, Igweze ZN,Orisakwe OE. Heavy metals in miscarriages and stillbirths in developing nations. Vol. 22, Middle East Fertility Society Journal. Middle East Fertility Society; 2017. p. 91–100.
18. Gaskins AJ, Rich-Edwards JW, Williams PL, Toth TL, Missmer SA, Chavarro JE. Pre-pregnancy caffeine and caffeinated beverage intake and risk of spontaneous abortion. Eur J Nutr [Internet]. 2018 Feb 1 [cited 2020 Aug 7];57(1):107–17. Available from: /pmc/articles/PMC5332346/?report=abstract
19. Lyngsø J, Ramlau-Hansen CH, Bay B, Ingerslev HJ, Hulman A, Kesmodel US. Association between coffee or caffeine consumption and fecundity and fertility: A systematic review and dose-response meta-analysis [Internet]. Vol. 9, Clinical Epidemiology. Dove Medical Press Ltd; 2017 [cited 2020 Jul 10]. p. 699–719. Available from: /pmc/articles/PMC5733907/?report=abstract
20. Van Heertum K, Rossi B. Alcohol and fertility: how much is too much? Fertil Res Pract [Internet]. 2017 Dec [cited 2020 Aug 7];3(1). Available from: /pmc/articles/PMC5504800/?report=abstract