Pregnancy and diet

Pregnancy and pre-pregnancy are both good times to think about healthy eating. What you eat now will help your baby to grow and develop healthily, giving them the best start in life. It will also be good for your health. This fact sheet is intended to support those considering pregnancy and those already pregnant with making healthy lifestyle choices. 

Healthy eating during pregnancy

This does not mean going on a special diet; simply follow general healthy eating guidelines, found in the BDA Healthy Eating food fact sheet.  

Eat regularly – three meals a day (and two to three snacks if needed). Don’t leave it longer than 12 hours between eating. If you don’t usually eat breakfast, start with a small snack in the morning.

Base meals on a variety of food groups (see BDA food fact sheet on portion sizes for more information). If you need extra energy, increase portions of protein and/or wholegrain carbohydrates.

Fluids (water, fruit teas, skimmed or semi-skimmed milk, fruit juice) are important to keep you hydrated. Nausea is worse when dehydrated.

• Have about 1900ml a day (about eight glasses) 
• Drink more if you’re being sick, the weather is hot or if exercising

Ensure good food hygiene practices

Foods to avoid or be careful with due to their possible risks to your baby:

Chilled food should be stored at the correct temperature (below 5°C). Foods should not be eaten after the ‘use by’ date. Wash soil from fruit, vegetables and salad. 

Alcohol in pregnancy 

UK guidelines recommend that for those planning pregnancy and those who are pregnant, the safest option is to avoid alcohol. Alcohol can increase the risk of miscarriage or your baby could develop a group of problems known as Foetal Alcohol Spectrum Disorder which include poor growth and learning and behavioural difficulties. If you have any concerns about alcohol consumption in pregnancy, speak to your midwife.

Smoking

You or your partner should not smoke during or prior to pregnancy. Smoking can harm your unborn baby by causing premature birth, low birth weight and other long-term health problems.  

Physical activity 

If you are pregnant, you should aim for at least 30 minutes of moderate intensity activity per day. If you have not been exercising, begin with no more than 15 minutes, three times per week - then increase gradually to 30 minutes. Those who regularly exercise before pregnancy are safe to continue.  

Top tips

1. Eating a varied diet including foods from the main food groups.
2. Include good sources of iron and calcium every day.
3. Have regular meals, e.g. breakfast, lunch & dinner (helps to reduce nausea). 
4. Take a daily supplement of 400mcg folic acid and 10mcg vitamin D. 
5. Those with more restrictive diets, e.g. vegans may benefit from other supplements (see our Plant-based diet Food Fact Sheet.)
6. If you opt for plant milks (as an alternative to cow’s milk), choose one that is fortified with calcium and iodine.
7. Avoid alcohol, smoking and certain foods (listed in the table above).
8. Exercise regularly.
9. If you need further support if you are under (BMI<18.5kg/m²) or over weight (BMI>25 kg/m²) or having a multiple pregnancy - ask to be referred to a dietitian.

Frequently asked nutrition questions

Do I need to be eating for two?

No. The amount you need to eat will depend on your Body Mass Index (BMI) at the start of your pregnancy (use this BMI calculator to find out your BMI). If you are of healthy BMI, an average adult needs around 1900kcal per day prior to pregnancy, your energy needs will increase by 200 kcal only in the third trimester.

How do I know that I am meeting my nutritional needs? 

By concentrating on a healthy varied diet and staying active your body should naturally gain sufficient weight for your baby to be born at optimum birth weight. This is important for them to continue to grow and develop well.

Currently there are no UK guidelines on appropriate weight gain during pregnancy. However, if you or your clinician are concerned and need a guide, the following table from the US Institute of Medicine (IOM) can be used as a guide. Maintain a weight gain graph for review to monitor progress in weight gain only if your clinician thinks it would improve your outcomes. If you are concerned about your weight, ask for a referral to a maternal dietitian.

* If your BMI is 35 or over, you and your healthcare team may aim for lower than 5kg weight gain to reduce adverse risks to you and your baby. 

** This is assuming weight gain of 0.5-2 kg in the first trimester.

When do I need to consider higher energy intake? 

If you are underweight or you continue to be very physically active throughout pregnancy, your energy requirements will need to increase to meet your needs for pregnancy, development of the foetus and creating reserves for lactation. The amount of energy increase would need to be individually assessed, if you are not gaining enough weight discuss with your midwife/GP or ask for a referral to a dietitian.   

Should I be worried about weight gain during pregnancy?

Weight loss is strictly not recommended during pregnancy as it can be harmful to the health of the growing baby. If you have a high BMI or are reducing your physical activity during pregnancy, your energy requirements may not change (see table above for a guide to weight gain and pregnancy). A dietitian would be able to guide you on avoiding excessive weight gain while ensuring you are eating well. 

Should I take additional nutritional supplements?

Yes. There are two vitamin supplements needed during pregnancy: folic acid and vitamin D. Those who follow a vegetarian/plant-based diet may need to take additional supplementation of iodine, omega-3 fatty acids and vitamin B 12 (see the BDA plant-based diet sheet). 

Folic Acid: This vitamin can help reduce the risk of your baby developing neural tube defects (NTDs). Take a supplement with 400 micrograms (mcg) of folic acid every day from pregnancy planning (as soon as you stop contraception) until week 12 of your pregnancy. If you are at an increased risk of having a baby with NTD, you may need to take more. 

Some people take a higher dose of folic acid. Why? 

You will need more folic acid (five milligrams (mg) a day) if your risk of having a baby with NTD is higher than normal. If you are at an increased risk, your doctor will need to prescribe the higher dose. You may be advised to take an increased dose if: you have had a previous pregnancy affected by NTD, you or your partner have NTD, you are taking certain medications for epilepsy, you have coeliac disease or diabetes, your BMI is 30 or more, you have sickle-cell anaemia or thalassaemia. Speak to your doctor if you think you may need a higher dose. 

Also include folate rich food in your diet (green vegetables, fortified bread and cereals). 

Vitamin D: Vitamin D helps to absorb calcium and is important for bone health; too little could cause rickets in your baby. Take a supplement of ten micrograms (mcg) of vitamin D every day throughout your pregnancy and when breastfeeding. Higher doses (25mcg) of vitamin D are likely needed for groups at increased risk (with increased skin pigmentation, reduced exposure to sunlight, or those who are socially excluded or living with obesity), but further evidence is needed to support this.

Iodine: If you are planning pregnancy, are pregnant or lactating have a higher requirement of iodine which can effectively be met with food sources such as fish, milk and dairy products. If you are vegan or have a compromised nutritional intake, it is recommended to take a supplement of 150 mcg daily. Those with pre-existing thyroid conditions need to discuss iodine requirements with their GP or maternal dietitian. 

Multivitamin: If you are taking a prenatal multivitamin, ensure that you only take the recommended dose as high levels of certain vitamins and minerals can be toxic to you and your baby. Do not take vitamin supplements that have vitamin A (retinol) in when you are pregnant as high levels can cause harm to your baby.

How to manage possible side effects during pregnancy

• Constipation - Eat wholemeal bread, high-fibre breakfast cereal, fruit and vegetables, drink plenty of water daily and regular physical activity.

• Feeling sick - Eating and drinking little and often can help. Prevent dehydration by drinking little and often. Ginger-rich foods/drinks, dry crackers and acupressure may be helpful. In 90 per cent of pregnancies, sickness resolves by 20 weeks. If your vomiting is very severe and you are unable to keep food/water down leading to dehydration, get medical advice promptly. 

• Heartburn/indigestion - Try eating smaller regular meals and snacks. Reduce caffeine and fatty, fried and spicy foods.