Pregnancy, Women's Wellbeing

The Best Possible Diet for the First Trimester of Pregnancy

This is the first of a 3-part series looking at nutrition through the different stages of pregnancy. This article deals with the 1st Trimester of pregnancy.

Other articles in the series are:



The Best Possible Diet for the First Trimester of Pregnancy

When you are in the early stages of pregnancy, especially if you are looking forward to your first child, a whole new world of information suddenly bombards you. Sometimes the transition into your ‘pregnant’ state of mind can be a challenge. You may take a while to get your head around how your behaviours and foods choices should change. Prioritisation is the key here. Your most immediate action list is as follows:

  • Go and talk to your GP, make sure that you are in receipt of the entire healthcare support package that you need. Your allocated midwife can then guide you through the ‘what to do when’
  • Make sure that you have a clear understanding about how you should alter your lifestyle and diet to avoid any risk to your baby.  Read Foods to Avoid When Pregnant
  • Educate yourself on optimal food and lifestyle choices. The rest of the action list you can get to later.

What is happening?

Pregnancy is divided into three stages or trimesters. Nutritional strategies for your first 12 weeks, or trimester of pregnancy are focussed on here. However, your health in pregnancy is not divided into these neat little stages – NO! Your nutritional and general health status is influenced by what you have been up to before you conceived! So, if you are planning to start a family make sure that you are already following the guidelines for eating for a healthy pregnancy, including supplementation.

Pregnancies are dated from the beginning of the last period but fertilisation normally takes place around ovulation at week 2, of a roughly 28 day cycle. Your first trimester progresses very quickly, as does the early development of your foetus.

By the time you are at 12 weeks and entering your second trimester all the organs and bone structures of your foetus are in place. The heart has starting beating although of course it is not fully formed. By around week 5, the neural tube will close, this will contain the developing structures for the brain, backbone and spine – one week after your period was due!. We will come onto neural development and nutrition later[1].

Good nutrition at the very start of your pregnancy is vital. The principles of healthy eating have never been more important than when you are first pregnant. Do not miss this opportunity to nourish your baby in the best way possible. Do not wait to follow the pregnancy guidelines until you have confirmation from your pregnancy test. If you are trying to become pregnant, it is best to follow a pregnancy diet, see below.

If your pregnancy was a unplanned, don’t panic – just get straight on to the dietary recommendations here.

Managing your food choices during the first 12 weeks of pregnancy

Pregnancy sickness –otherwise known as morning sickness

You may be feeling queasy with a range of sickness symptomsranging from ‘going off’ foods to violent daily sickness. The exact cause of morning sickness is not known, although it is thought to be a way that nature defends the foetus from foods that may be contaminated by toxins or bugs[2]. Follow some simple tips to reduce nausea:

  • Eat little and often
  • Choose plain foods, but make sure that these are nutritious
  • Do not eat a large plateful of anything
  • Make sure that you drink plenty of fluids, preferably water or herbal teas. Vomiting can dehydrate you.
  • Consider visiting an acupuncturist, there is some evidence that acupressure points can help with feelings of nausea (but not frequency of vomiting)[3]
  • Try drinking tea containing ginger (either tea bags or fresh chunks). Ginger has been shown to help[4], you could alternatively cook with ginger.
  • Vitamin B6 may help with nausea and vomiting, make sure your prenatal supplement contains the recommended daily allowance[5].
  • Episodes of nausea and vomiting have been shown to reduce significantly when treatment with B6 and ginger are combined[6].
  • There has been suggestion that hypnotherapy can help with nausea and vomiting during pregnancy[7].

If you are suffering from nausea and vomiting during your first trimester, make sure that you mention it to your midwife. There may be other factors causing your illness and they should be eliminated.

Fatigue and sugar cravings

It is also common to feel tired during the first trimester of pregnancy. It goes without saying that you need to make sure that you rest as much as possible. It is also important that you get checked by your midwife or GP for deficiencies, most significantly iron. Ask for a blood test to eliminate anaemia.

Beware, it is tempting to prop yourself with sugary snacks and quick release foods – especially since the ‘grab a cup of tea of coffee’ quick fix is not an option! This strategy will probably make you feel gradually worse and gain unnecessary weight. By eating calories lacking nutritional value you are depriving your foetus of the nutrients contained within more wholesome options. Eat meals little and often and avoid big meals. Make sure every single mouthful you eat follows these recommendations:

  • Aim to include protein in every meal or snack to slow down the release of the sugars into the blood, it can also make you feel fuller for longer.
  • Increase the amount of fibrous foods that you eat. Good examples include: dark green leafy vegetables, beans, lentils and apples and pears.
  • Avoid refined foods. Replace white (refined) flours with brown/wholegrain (complex) flours. Buy brown pasta, rice and wholegrain bread.
  • Processed foods and ready meals are most likely to contain refined carbohydrates, do not eat them, they are usually low in nutrients anyway.
  • Make breakfast the biggest meal of the day.
  • Carry protein rich and healthy snacks with you at all times to help you to resist reaching for a biscuit or chocolate bar. Look out for snack bars that contain protein.
  • Drink water – drink 8 glasses per day to avoid dehydration which can lead to fatigue and cravings for high energy foods.

Needing to wee more and hydration

One of the symptoms of being pregnant is needing to go to the loo all the time. This is caused by the changes in hormones associated with pregnancy and an increased amount of blood in your body – both of which increase the flow through your kidneys to produce more urine. Again, mention how often you are going and how much to your midwife. You need to eliminate frequent urination as a sign of ill health e.g. gestational diabetes or a urinary tract infection. The latter can be very common in pregnancy. You must not deprive your body of water during this time. You could consider avoiding diuretic foods and drinks – you will be avoiding caffeine colas anyway, but many sodas can be dehydrating. Diuretic foods include: asparagus, artichoke, apple cider vinegar, celery, lemon, fennel, watermelon.

Feeling light headed and dizzy

Make sure you record feeling dizzy or faint with your midwife. Your body is busy producing more and more blood which will be used in the placenta and absorbed into your baby. This change to your cardiovascular system can be the cause of feeling faint. Alternatively you may have low blood sugar or you could be dehydrated.

Eating for 2? How much? Too much?

Whilst it is healthy to make sure that you are gaining enough weight in pregnancy, gaining too much or too little can lower chances for good health for you and your baby. You may be eating for two, but you do not need to increase your daily calorific intake in the first trimester8. Beware if you are eating to pep up your energy supplies, see above.

Nutritional specifics of the first trimester

The most important nutrients.

We should be able to get all we need from a healthy balanced diet – but do we? Prenatal supplementation is widely acknowledged to be a good idea during pregnancy. The government recommends supplementation with Folic acid, Vitamin D as a minimum. 

Here we will outline the nutrients that are most relevant to your first 12 weeks of pregnancy. Do note however, this is just of list of priorities and is not exclusive. Whole foods contain a complex number of nutrients for a reason; they work with each other both in the plants, grains or animals and in our bodies. We do not fully understand these interrelationships, but we do know that supplementing some nutrients without others can throw us out of balance. For this reason we recommend a specifically developed multivitamin and mineral formulation for preconception and throughout pregnancy. In addition, where there is a deficiency of folic acid for example, it is likely that a woman is deficient in a range of nutrients[8].

Folic Acid

Having optimal folic acid is well documented as crucial for the normal development in the ‘neural tube’. Deficiency in folic acid is associated with neural tube defects e.g. spina bifida. A study showed that pregnancies resulting in neural tube defects correlate with significantly lower folic acid and B12 levels in the first trimester of pregnancy[9]. A study across 33 locations supplemented women with 400ug of folic acid and found a 72% protective effect, this study measured the impact of supplementing with other nutrients, none of which had any significant effect on neural tube risk[10]. Make sure that your prenatal supplement contains at least 400ug of folic acid. NOTE: the neural tube closes in week 5 of pregnancy. Evidence from a recent UK study showed that only 12% women took folic acid supplements before falling pregnant and only 17% before neural tube closure [10]. Folate supplementation has also been found to improve birth weight, head circumference and length of newborn babies[11].


A deficiency in B12 is associated with neural tube defects. Vegetarians and vegans should be aware that they are at significant risk of a B12 deficiency. Vitamin B12 works with folic acid to clear a potentially toxic by product of body processes, homocysteine. Low B12, folic acid and high homocysteine levels in the body during pregnancy are associated with birth defects and pregnancy complications[12].


Low iron status can be common in pregnancy. It is therefore important to check that anaemia is not the cause of low energy or fatigue. A study in the USA found that 8% of women had low iron status in the first trimester of pregnancy[13]. Although the research is not consistent, low iron status has been associated with low birth weight, small for gestational age and preterm delivery[13].

Vitamin D

Vitamin D status has been widely reported to be alarmingly low in the UK. Vitamin D supplementation is recommended by the government throughout pregnancy. Low Vitamin D status is associated with increased risk of preeclampsia[14]. Low Vitamin D status in the first trimester could be associated with low birth weight for gestational age[15], although there is some conflict in the evidence. Vitamin D also works with Calcium to build the structure and strength of bones in the growing foetus. Both should be included in a prenatal multivitamin and mineral supplement.


Zinc is important in pregnancy as it influences cell division, growth and development of the foetus. Zinc levels in the body steadily lower during pregnancy[16]. Mild zinc deficiency is associated with low birth weight, slowed growth in the uterus and preterm delivery[17].

Omega 3 and DHA

As we have discussed the development of all of your baby’s body organs starts in the first few weeks of your pregnancy. Omega 3 and 6 fats are essential for the health of every human cell. They are found in highest concentrations in the brain and nervous system and are known to be important in cell division, cell communication and inflammation in the body. They make up a large proportion of the membrane of every living cell[18]. Omega 3 supplementation improves length of gestational period and birth weight[19] and mental performance of the child[20]. Higher intake of omega 3 fats EPA and DHA are also associated with reduced risk of preeclampsia [21].


We have focussed on the nutritional needs of pregnant women during the first 12 weeks of pregnancy, although the generic advice for pregnancy applies throughout your pregnancy including the first 12 weeks. There are specific symptoms associated with the first trimester of pregnancy and we have aimed to tackle these issues and suggest some strategies to reduce suffering. Throughout pregnancy do not forget the importance of good nutrition and sensible lifestyle choices- the research is there to prove it!


1 Cannon E, 2011, You and your bump, Macmillan, London

2 Quinla JD, Hill DA, 2003, Nausea and Vomiting in Pregnancy, American Family Physician, 68:121-128

3 Belluomini J, Litt RC, Lee KA, Katz M, 1994, Acupressure for nausea and vomiting of pregnancy: a randomised, blinded study, Obstetrics and Gynecology, 84:245-248

4 Borrelli F, Capasso R, Aviello G, Pittler M, Izzo A, 2005, Effectiveness and Safety of Ginger in the Treatment of Pregnancy-Induced Nausea and Vomiting, Obstetrics and Gynecology, 105:849-859

5 Sahakian V, Rouse D, Sipes S, Rose N, Niebyl J, 1991, Vitamin B6 is effective therapy for nausea and vomiting of pregnancy: a randomized, double blind placebo controlled study, Obstetrics and Gynecology, 78:33-36

6 Sripramote M, Lekhyananda N, 2003, A randomised comparison of ginger and vitamin B6 in the treatment of nausea and vomiting of pregnancy, Chot Mai Het Thang Phaet, 86:846-853

7 Galen Buckwalter J, Simpson SW, 2006, Psychological factors in the etiology and treatment of severe nausea and vomiting in pregnancy, American Journal of Obstetrics and Gynecology, 186:S210-S214

8 Derbyshire E, 2011, Nutrition in the Childbearing Years, Wiley Blackwell, London

9 Wald NJ, Hackshaw AK, Stone R, Nefertiti A, 1996, Blood folic acid and vitamin B12 in relation to neural tube defects, BJOG: An International Journal of Obstetrics and Gynaecology, 103:319-324

10 No authors listed, MRC Vitamin Study Research Group, 1991, Prevention of neural tube defects: results of the Medical Research Council Vitamin Study, The Lancet, 338:131-137

11 Tamura T, Goldenburg R, Freeberg LE, Cliver SP, Cutter GR, Hoffman HJ, 1992, Maternal serum folate and zinc concentrations and their relationships to pregnancy outcome, American Journal for Clinical Nutrition, 56:365-370

12 Refsum H, 2001, Folate, vitamin B12 and homocysteine in relation to birth defects and pregnancy outcome, British Journal of Nutrition, 85:109-113

13 Scanlon K, Yip R, Schieve LA, Cogswell ME, High and low Hemoglobin Levels During Pregnancy: Differential Risks for Preterm Birth and Small for Gestational Age, Obstetrics and Gynecology, 96:741-748

14 Bodnar LM, Catov JM, Simhan HN, Holick MF, Powers RW, Roberts JM, 2007, Maternal Vitamin D deficiency increases risk of preeclampsia, Journal of Clinical Endocrinology, 92:3517-3522

15 Nassar N, Halligan GH, Roberts CL, Morris JM, Ashton AW, 2011, Systematic review of first trimester vitamin D normative levels and outcomes of pregnancy, American Journal of Obstetrics and Gynecology, 205:208e1-7

16 Ruiz NF, Meertens L, Pena E, Sanchexz Am Solano L, 2005, Behaviour of serum zinc levels during pregnancy, Archivos Latinamericanos de Nutricion, 55:235-244

17 Caulfield LE, Zavaleta N, Shankar AH, Merialdi M, 1998, Potential contribution of maternal zinc supplementation during pregnancy to maternal and child survival, American Journal of Clinical Nutrition, 68:499-508

18 Greenberg JA, Bell SJ, Van Ausdal W, 2008, Omega-3 Fatty Acid supplementation During Pregnancy, Obstetrics and Gynecology, 1:162-169

19 Olsen SF, Sorensen JD, Secher NJ, 1992, Randomised controlled trial of effect on fish-oil supplementation on pregnancy duration, Lancet, 339:1003-1007

20 Dunstan JA, Simmer K, Dixon G, Prescott SL, 2008, Cognitive assessment of children at age (2 ½) years after maternal fish oil supplementation in pregnancy: a randomised controlled trial, Archives of Disease in Childhood. Fetal and Neonatal Edition, 93:F45-F50

21 Oken E, Ning Y, Rifas-Shinman SL, Rich-Edwards JW, Olsen SF, Gillman MW, 2007, Diet during pregnancy and risk of preeclampsia or gestational hypertension, British Journal of Nutrition, 98:873-877

Disclaimer: Seven Seas Life is not intended to provide medical advice, diagnosis or treatment. The articles are based on peer reviewed research, and discoveries/products mentioned in the articles may not be approved by our regulatory bodies, you will find no mention of Seven Seas products within the pages of the Seven Seas Life Section..Read more

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