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Lifestyle in NICE guidance – Part 4a – Weight & Pregnancy

I know body changes during pregnancy are a really sensitive matter for many. Even those who have not had any issues with body image previously can, understandably, experience difficulty with how rapidly their body is changing and how out of control this is for them. This said, I do think it’s important for people to know how weight can affect their health, the health of their baby and their pregnancy.

Today I’ll be discussing NICE guidance “Weight management before, during and after pregnancy”. (Public health guidance [PH27]). I will also be including some extra bits of info, where relevant, which relate to this guidance but are from a recent course I did on the relationship between nutrition, fertility and pregnancy from Monash University in Melbourne. I have highlighted these extra bits of info by them being in blue text to make it clear what constitutes NICE guidance and what is not.

As always, I have highlighted aspects of this guidance which relate to lifestyle and to condense them into a readable blog. For those who are interested and want to read the full guidance, as usual the link to this is at the end.


Weight management: a definition

Weight management includes:

  • assessing and monitoring body weight.
  • preventing someone from becoming overweight (body mass index [BMI] 25–29.9 kg/m²) or obese (BMI greater than or equal to 30 kg/m²).
  • helping someone to achieve and maintain a healthy weight before, during and after pregnancy by eating healthily and being physically active and gradually losing weight after pregnancy.

Achieving and maintaining a healthy weight

Women will be more likely to achieve and maintain a healthy weight before, during and after pregnancy if they:

  • eat fibre-rich foods such as oats, beans, peas, lentils, grains, seeds, fruit and vegetables, as well as wholegrain bread and brown rice and pasta.
  • eat at least five portions of a variety of fruit and vegetables each day, in place of foods higher in fat and calories.
  • eat as little as possible of fried food; drinks and confectionery high in added sugars (such as cakes, pastries and fizzy drinks); and other food high in fat and sugar (such as some take-away and fast foods).
  • watch the portion size of meals and snacks, and how often they are eating.
  • make activities such as walking, cycling, swimming, aerobics and gardening part of everyday life and build activity into daily life – for example, by taking the stairs instead of the lift or taking a walk at lunchtime.
  • minimise sedentary activities, such as sitting for long periods watching television, at a computer or playing video games.
  • walk, cycle or use another mode of transport involving physical activity.

Effective weight-loss programmes:

  • address the reasons why someone might find it difficult to lose weight
  • are tailored to individual needs and choices
  • are sensitive to the person’s weight concerns
  • are based on a balanced, healthy diet
  • encourage regular physical activity
  • expect people to lose no more than 0.5–1 kg (1–2 lb) a week
  • identify and address barriers to change.

Weight loss programmes are not recommended during pregnancy as they may harm the health of the unborn child.

Reputable sources of information and advice about diet and physical activity for women before, during and after pregnancy include: ‘The pregnancy book’, ‘Birth to five’ and the ‘Eat well’ website.

Why is weight important?



Women of a healthy weight have higher fertility rates than those who are underweight, overweight or obese. The Nurse’s Health Study II, a US population-based prospective cohort study of over 116,000 nurses, found that 20,417 women experienced infertility between 1989 to 1995.

They also reported a strong U-shaped association with BMI and risk of anovulatory infertility. In women who are overweight or obese, infertility is largely related to increased adiposity and subsequent alterations in hormone production, secretion and bioavailability.

Functions that are affected include ovulation, menstruation, oocyte development, embryo development, endometrial development, implantation and miscarriage.

Weight-loss of 5-10% can increase fertility, however, sometimes women (and their offspring) may benefit from more weight-loss than this before becoming pregnant. This is because pre-pregnancy weight status is a strong predictor of pregnancy outcomes. Therefore, being as close as possible to a healthy weight-range and optimising fitness prior to conception is advised


Maternal malnutrition and overnutrition in pregnancy

Consequences of maternal malnutrition Consequences of maternal overnutrition
To maternal health:

·         Increased risk of maternal complication & death

·         Increased infection

·         Anaemia

To foetal & infant health:

·         Increased risk of foetal, neonatal & infant death

·         Intrauterine growth retardation, low birth weight, prematurity.

·         Birth defects

·         Cretinism

·         Brain damage

·         Increased risk of infection

·         Increased risk of chronic metabolic disease


To maternal health:

·         Increased risk of maternal obstectric complications, including pre-eclampsia & gestational diabetes.

·         Increased risk of excessive gestational weight gain.

·         Increased risk of weight retention post-pregnancy

To foetal & infant health:

·         Increased birthweight and excess neonatal adiposity

·         Increased incidence of cardiovascular risk factors in children

·         Increased risk of obesity, type 2 diabetes and metabolic syndrome in adulthood.

Changing behaviour

Evidence-based behaviour change advice includes:

  • understanding the short, medium and longer-term consequences of women’s health-related behaviours.
  • helping women to feel positive about the benefits of health-enhancing behaviours and changing their behaviours.
  • recognising how women’s social contexts and relationships may affect their behaviour.
  • helping plan women’s changes in terms of easy steps over time.
  • identifying and planning situations that might undermine the changes women are trying to make and plan explicit ‘if–then’ coping strategies to prevent relapse.



If a pregnant woman is obese this will have a greater influence on her health and the health of her unborn child than the amount of weight she may gain during pregnancy. That is why it is important, when necessary, to help women become a healthy weight before they become pregnant.

**Dieting during pregnancy is not recommended as it may harm the health of the unborn child.**

The amount of weight a woman may gain in pregnancy can vary a great deal. Only some of it is due to increased body fat – the unborn child, placenta, amniotic fluid and increases in maternal blood and fluid volume all contribute.

Many pregnant women ask health professionals for advice on what constitutes appropriate weight gain during pregnancy. However, there are no evidence-based UK guidelines on recommended weight-gain ranges during pregnancy.

Of note – this is not the case for all countries, guidance for women in Australia is as follows:

Pre-pregnancy BMI Recommended weight gain during pregnancy Weight gain in the 1st trimester Expected rate of weight gain in 2nd + 3rd trimesters
<18.5 12.7-12.8 kg  

1 – 2 kg

2.1-2.5 kg/month
18.5 – 24.9 11.3-15.9 kg 1.6-2.2kg/month
25 – 29.9 6.8-11.3 kg 1.2kg/month
>30 5-9 kg <1.2 kg/month

 What action should health professionals take?

  • At the earliest opportunity, for example, during a pregnant woman’s first visit to a health professional, discuss her eating habits and how physically active she is. Find out if she has any concerns about diet and the amount of physical activity she does and try to address them.
  • Advise that a healthy diet and being physically active will benefit both the woman and her unborn child during pregnancy and will also help her to achieve a healthy weight after giving birth. Advise her to seek information and advice on diet and activity from a reputable source.
  • Offer practical and tailored information.
  • Dispel any myths about what and how much to eat during pregnancy. For example, advise that there is no need to ‘eat for two’ or to drink full-fat milk. Explain that energy needs do not change in the first 6 months of pregnancy and increase only slightly in the last 3 months (and then only by around 200 calories per day).

Again, in Australia there are some clearer guidelines on this:

During the first trimester women do not require any extra energy from food. During the second trimester energy requirements increase by approximately 330 kcal. This is equivalent to one tub of yoghurt, one cereal bar and one piece of fruit.

During the third trimester, energy requirements increase by approximately 450 kcal. This is equivalent to one bowl of cereal with milk plus one cheese sandwich.

While additional energy requirements during pregnancy are relatively low, the requirements for most nutrients increase. This means that mothers should focus on nutrient-rich foods.

Overall, the key to the pregnancy diet is quality, not quantity.

That’s all for today, I’ll continue this in a part b next week, the link to the full guidance will be at the end of this upcoming post where I discuss more about pregnancy and post-pregnancy .

Emma x

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