Healthy Weight Gain During Pregnancy: How Much is too Much?

Pregnancy is a time of change. It is likely that, in preparation for your new arrival, you will make changes to your home and changes to your lifestyle. You may find your feelings and emotions become slightly erratic and it is a time when many women reevaluate what is important to them. Perhaps the most outwardly obvious changes are those that affect your body; from the things you expect, such as an expanding abdomen and larger breasts, to those that are more surprising, including changes in foot size and extra inches gained elsewhere. Weight gain during pregnancy is normal, but how much is too much and how do you ensure that you stay healthy throughout.

Some women relish pregnancy and the immediate postnatal period, taking the time to relax their regular eating plans and exercise routines, and making the most of their legitimate weight gain. For other women, the lack of control they have over their weight, in combination with their ever expanding waistline is a source of stress and anxiety, turning what should be a time of eager excitement into a period of self angst and reduced confidence.

There are several things to bear in mind about weight gain during pregnancy:

1. There are no standard recommendations for how much weight a woman should gain during pregnancy.

At one time there used to be strict guidelines advocating that weight gain during pregnancy should be limited to a few kilograms (KGs). Fortunately, progress has been made in the field of women’s healthcare and doctors are now encouraged to take a much more individualised approach. Weight gain is known to vary considerably between women and depends a lot on pre-pregnancy Body Mass Index (BMI).

The US Institute of Medicine (IOM) published guidelines linking pregnancy weight gain with BMI before conception:

• BMI <18.5. Underweight. Recommended gain 12.5 – 18.0 kg.
• BMI 18.5 – 24.9. Normal weight. Recommended gain 11.5 – 16.0 kg.
• BMI 25 – 29.9. Overweight. Recommended gain 7.0 – 11.5 kg.
• BMI >30. Obese. Recommended gain 5.0 – 9.0 kg.

Whilst these are American guidelines, they are utilised by doctors around the world and should be applicable to most women in other developed countries. It is important however, to consider each woman individually, particularly in countries where women do not receive comprehensive prenatal care and in areas where women face emotional and physical challenges.

Women who are pregnant with twins, triplets, or more, should, naturally, anticipate gaining extra weight during their pregnancies.

2. Your developing baby is not the only source of increased weight

The NHS estimates that the average woman will gain 10 – 12.5 kg whilst pregnant. The average newborn weighs between 2.5 and 4.5 kg. So, why the discrepancy? What is causing the extra increase in weight, over and above the mass of the developing baby?

The following factors will all contribute to the extra KGs gained during pregnancy:

•  Placenta
•  Amniotic fluid
•  Extra water
•  Breast growth
•  Increased blood supply
•  Larger uterus.

The body will also be storing fat in preparation for breastfeeding

3. The consequences of gaining too much weight……

Women who gain too much weight during pregnancy have an increased risk of gestational diabetes and pre-eclampsia. If you are gaining more than 0.5 kg every week, or experience very fast, extreme weight gain (≥ 1 kg in a week) you should seek medical advice. This can be an early sign of pre-eclampsia, which can rapidly develop into a serious complication and will require careful monitoring throughout the remainder of your pregnancy.

Excess weight gain can also increase the likelihood of needing a Caesarean and giving birth to a baby with above average birth weight (known as macrosomia). Women delivering larger babies are more likely to struggle during delivery and ultimately require interventions and their babies have a higher risk of sustaining injuries at birth.

Losing the weight they have gained during pregnancy is a significant issue for many new mothers. Those who have gained excess weight are likely to find it harder to lose after giving birth and if they implement too strict a diet they risk reducing their milk supply.

4. …..and the consequences of not gaining enough weight.

Some women struggle to put on enough weight during pregnancy, particularly those who have a slim build prior to falling pregnant. It is not unusual for weight gain to be minimal, or even none existent during the first trimester. Those women who struggle with morning sickness in the first few months of pregnancy may even find that they lose weight initially. This will not usually be cause for alarm, although it is likely that your doctor will monitor you closely to ensure that you do start to gain weight as your pregnancy progresses. It is normal to gain more weight towards the end of pregnancy than at the start.

The major risks associated with gaining too little weight during pregnancy are premature labour and low birth weight. Furthermore, women who do not store enough fat reserves during pregnancy may find breastfeeding more difficult. Exclusive breastfeeding is recommended by the World Health Organisation, for all babies for the first six months.

5. How to manage weight gain during pregnancy

In an ideal scenario, all women would achieve a slow and steady weight gain during pregnancy. This minimises health risks to both mother and baby and increases the likelihood of losing those extra kgs post delivery. The optimal way of doing this is by consuming a balanced, nutrient rich diet and partaking in regular bouts of moderate exercise.

Pregnant women should start every day with a healthy, balanced breakfast, eat fibre-rich foods, choose whole grain bread, rice and pasta where possible, eat at least five portions of fruits and vegetables a day and be mindful of portion sizes.  For most women pregnancy is not the time to initiate a low calorie diet (or in fact, a diet of any sort) or a vigorous exercise routine. However, obese women (BMI of over 30 before pregnancy) should modify their diet and get more exercise to lower their risk of gestational diabetes. Anyone who is worried should speak to their doctor about the safest way of managing their weight during pregnancy.

Consider Nabta’s 4 Week prenatal course to learn more

Nabta is reshaping women’s healthcare. We support women with their personal health journeys, from everyday wellbeing to the uniquely female experiences of fertility, pregnancy, and menopause.

Get in touch if you have any questions about this article or any aspect of women’s health. We’re here for you.

Sources:

• “How Much Weight Will I Put on during My Pregnancy?” NHS Choices, NHS, https://www.nhs.uk/common-health-questions/pregnancy/how-much-weight-will-i-put-on-during-my-pregnancy/.
• InformedHealth.org [Internet]. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006-. Pregnancy and birth: Weight gain in pregnancy. 2009 Jun 17 [Updated 2018 Mar 22]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK279575/.
• Institute of Medicine (US) and National Research Council (US) Committee to Reexamine IOM Pregnancy Weight Guidelines; Rasmussen KM, Yaktine AL, editors. Weight Gain During Pregnancy: Reexamining the Guidelines. Washington (DC): National Academies Press (US); 2009. Summary. Available from: https://www.ncbi.nlm.nih.gov/books/NBK32799/.
• “Pregnancy Weight Gain: What’s ‘Normal’ in Stones and Kg.” NCT (National Childbirth Trust), Sept. 2018, https://www.nct.org.uk/pregnancy/food-and-nutrition/pregnancy-weight-gain-whats-normal-stones-and-kg.
• “Weight Gain During Pregnancy.” ACOG, Jan. 2013, https://www.acog.org/Clinical-Guidance-and-Publications/Committee-Opinions/Committee-on-Obstetric-Practice/Weight-Gain-During-Pregnancy.