Weight gain in pregnancy: what’s normal?

Expert advice on normal weight gain in pregnancy, how to calculate how your pregnancy weight gain by trimester and what to do if you’re pregnant and overweight


Being pregnant makes you hungry (well, after you’re got over the feeling-sick bit). And, though most of us know full well that you don’t have to ‘eat for two’, almost half of mums-to-be put on more weight during pregnancy than the guidelines advise.


“I went up from 79kg to about 90kg but went straight back down to 84kg after the birth,” LH86 on our forum says. “Just waiting for my c-sec wound to heal so I can start exercising and walking about again to lose the baby weight.”

“I have put on about a stone so far  – I’m 33+2,” says mummyphoebe. “I was under 8 stone and my BMI was 17 before I was pregnant so needed to put on more but haven’t.

“If you are eating normally and baby is growing well then I think that is fine.”

So, how much weight should you put on?

There are no formal UK-specific health guidelines on weight gain in pregnancy. But as a rule of thumb the heavier you were before you got pregnant, the less weight you should put on during your next nine months.

For most mums-to-be, with a healthy pre-pregnancy weight, doctors recommended gaining between 11-16kg (25-35lb or 1.8 to 2.5 stone) over the full nine months.

In reality this means, “gaining one to five pounds in the first trimester and about one pound per week (or every 9 days) for the rest of your pregnancy for the optimal growth of your baby”, explains senior nutritionist Saidee Bailey, director of Perfect Start Pregnancy.

How fast should I put it on?

Not all at once! We’re talking gradual weight gain rather than pigging out and piling on the pounds.And if you’re already overweight you need to be even more careful; a recent study of 44,000 women in the US, published in Obstetrics & Gynecology, found that women who were overweight or obese before pregnancy were two to three times more likely to gain more weight than recommended, compared with those of normal weight.

Here’s a guide:

First trimester – most women don’t need to gain much weight, which is good news if you’re struggling with morning sickness. A few pounds, or less than 2kg, is fine in the first few months.

Second trimester – gain three to four pounds (about 1.4 to 1.8kg) a month. Try adding more zinc – from foods like lamb, turkey, chickpeas, spinach and brazil nuts – notes Saidee. “Zinc is required for rapid cell growth and is really important in your second trimester as your baby starts to really grow,” she explains.

Third trimester – gain three to four pounds (about 1.4 to 1.8kg) a month. Building up vitamin K stores – which help blood to clot – with foods such as banana, potato skins, Brussels sprouts, prunes and cabbage, is important this trimester, adds Saidee.

What if I’m having twins?

Forget everything! You can up the numbers if you’re having more than one baby; typical weight gain for mums-to-be of twins is around 50% more than in a single pregnancy.

Being pregnant with twins puts extra demands on your body, so paying attention to your diet will have lasting health benefits for you and your twins. It’s one of the most important steps you can take to give your twins a good start.

Experts say you’ll need 50%-100% more of the essential nutrients too, such as folic acid, vitamin B12, iron and calcium, with twins. While the best way to get these is through food, nutritionists and some midwives recommend a daily pre-natal vitamin and mineral supplement.

Will I be weighed during my pregnancy?

In the UK, pregnant women are weighed when they first see a midwife – but guidelines from advisory body the National Institute for Health and Care Excellence (NICE) warn GPs and midwives not to get the scales out routinely after that.

What’s BMI?

Pregnancy weight gain recommendations vary depending on whether you’re underweight or overweight to begin with. The best way to work this out is by calculating your Body Mass Index (BMI).

To do to this calculation divide your pre-pregnancy weight (in kilograms) by your height squared (in metres).

Then look at our pregnancy weight-gain chart, belowand see what’s the recommended weight gain for you:

  • BMI below 18.5 (underweight) – aim to put on 28-40lb (12-18kg)
  • BMI 18.5-24.9 (normal) – aim to put on 25-35lb (11-16kg)
  • BMI 25-29.9 (overweight) – aim to put on 15-25lb (7-11kg)
  • BMI above 30 (obese) – aim to put on 11-20lb (5-9kg)

But according to independent midwife Jacqui Tomkins, from the London Birth Practice, it’s crucial to remember that everyone is different.

“It is a mistake to try to determine very concretely how much you should be putting on, as there can be a number of compounding factors,” explains Jacqui, who was been named as the British Journal of Midwifery’s Midwife of the Year 2014.

Pregnancy BMI Weight Gain Chart

What are the risks if I put on too much pregnancy weight?

Overweight pregnant women are up to three times more likely to need an emergency Caesarean, according to a report from the NUI Galway Dept of Obstetrics and Gynaecology.

Other risks of being overweight when pregnant include:

And then, of course, there’s the discomfort of hauling round a heavier pregnant body – and the depressing thought of extra weight to lose after the birth. though some of our mums are actually excited bout getting back on a diet!

“I had a massive growth spurt at 34 weeks and put on over half a stone in a fortnight,” Strawberry Girl tells us. “In total it must now be 3 and a half stone though most of that in the last month or so to be honest.

“I can feel where it’s gone on more than you can see it (if that makes sense) and quite honestly I can’t wait to get back to Slimming World as soon as I can!! I really am not enjoying my double chin!!!!”

Can my weight gain be harmful for my baby?

There’s an increasing amount of research that says, ‘yes’.

Gaining an excessive amount of weight during your pregnancy means there’s a chance that your baby will be macrosomic, or Large-for-Gestational Age (LGA). And whilst we all love a big bouncing baby, weighing 4.5kg (8.8lbs) or more at birth can have serious implications for you and your newborn.

Risks of having a macrosomic baby include:

  • Increased chance of having caesarean section
  • Trauma to the birth canal
  • Shoulder dystocia – during labour your baby’s head is born but their shoulders get stuck
  • Brachial Plexus injuries – damage to the collection of nerves around the shoulder during birth
  • Facial nerve injuries – damage to the facial nerves during birth
  • Birth asphyxia – your baby is starved of oxygen during labour

What’s more, it’s worth knowing that women who gain more weight than recommended during pregnancy may be more likely to have an overweight child.

An American study of the health records of 4,145 women, and the medical records of their children between ages 2 and 5 found that women with a normal BMI before pregnancy, who gained more weight than recommended, were 80 percent more likely to have an overweight or obese child.

“Gaining…too much weight in pregnancy may permanently affect mechanisms that manage energy balance and metabolism in the offspring, such as appetite control and energy expenditure,” said study researcher Sneha Sridhar, a public health researcher at Kaiser Permanente division of research in Oakland, California.

“This could potentially have long-term effects on the child’s subsequent growth and weight,” Sridhar said.

What are the risks if I don’t put on enough pregnancy weight?

Interestingly, gaining too little weight may also lead to your baby becoming obese in later life. The same study found that 19.5 % women who gained less than the recommended weight also had children who were obese or overweight.

But being underweight or under-eating in pregnancy also has other risks including:

  • Premature birth
  • Having a small, weak baby with ongoing health problems
Not all baby: Pregnancy weight gain

But surely I need to eat more – I’m growing a baby!

No. Sadly, that’s not the case.

“You should eat the same amount as a non-pregnant woman (about 2000 calories) for the first 6 months,” says nutritionist Anne Sidnell. “And then in the last 3 months of your pregnancy, you need just 200 more calories a day, while your baby has their biggest growth spurt and you create nutrient stores for breastfeeding.”

Tempted as you may be to binge on buns while you’ve got an excuse for a big tummy, Anne says it’s more important than ever to focus on the quality of your pregnancy diet. After all, you’re nourishing a growing baby inside you.

Try to keep your food healthy and varied. This means lots of fruit and vegetables, and starchy foods such as bread, pasta, rice and potatoes, with moderate amounts of meat, fish and dairy.

  • Find out which foods you can and can’t eat safely during pregnancy.

How much is an extra 200 calories, exactly?

Brace yourself for the bad news: it’s not as much as you might think. It works out at about:

  • A small pitta bread filled with cottage cheese (222 cals)
  • 2 slices of malt loaf (188).

What if I’m overweight already?

Many women who are overweight will sail through their pregnancies. However, it’s worth knowing that being overweight and having a high BMI (of over 30) could put you and your baby at risk of complications such as:

  • Gestational diabetes
  • High blood pressure
  • Pre-eclampsia
  • Early labour

During labour, being overweight might also mean you might have:

  • Forceps or a ventouse birth
  • A caesarean section
  • Heavy bleeding after birth
  • A blot clot in your leg (DVT; Deep Vein Thrombosis) or your lung (pulmonary embolism or PE)

But remember, you might not experience any of these complications; it’s just good to know about them.

What if I’ve still not lost weight from my first pregnancy?

Losing the baby weight is something that we all worry about but it really is best to try and get back to your pre-pregnancy weight before you get pregnant again.

That’s because putting on weight between pregnancies has been shown to increase your risk of developing gestational diabetes and high blood pressure during subsequent pregnancies. In one study of 22,000 women in Northern California the women who developed gestational diabetes in their second pregnancy but who hadn’t developed it in their first were those who had had gained the most weight between pregnancies.

And in fact, it’s thought that even a relatively small gain of 1-2 BMI units (kg/m2) between pregnancies may increase the risk of gestational hypertension and gestational diabetes, even in women who are not overweight or obese according to a Swedish study of 151 025 women. It also increases the likelihood of giving birth to a large baby.

Do I need to change my lifestyle?

Looking after yourself means that you’re looking after your baby too.

Results of the world’s biggest study into the advice given to overweight pregnant women showed that education on eating well, avoiding a diet high in saturated fats and walking daily reduced the number of overweight women who had complications at birth.

Researchers at the University of Adelaide, writing in the journal BMC Medicine, reported a significant reduction in the number of babies born over 4kg to women who received diet and lifestyle advice during pregnancy.

The researchers also noted a range of other benefits for the babies of the women in the study, including a reduced chance of moderate to severe respiratory distress syndrome and reduced length of stay in hospital.

Should I diet?

No! Now is not the time to worry about weight loss. One reason for this is because during pregnancy your body changes the way it uses the energy we get from food.

Suddenly feeling like you could eat a horse is common when you’re pregnant and this happens because between meals your blood sugar drops to very low levels. Snacking is an essential part of pregnancy, so restricting what you eat will leave you very, very hungry.

What about exercise?

Something like a simple pregnancy exercise workout can help you maintain a healthy increase in pregnancy weight. Also, having a good level of fitness during pregnancy can help make labour easier: the fitter you are, the better your stamina and your ability to cope with giving birth.

Be careful with your choice of exercise, though. Make sure you know which exercise is safe during pregnancy.


“Don’t take up strenuous activity if you’re not used to it,” says specialist prenatal personal trainer Vicky Warr. “Choose a low-impact activity that won’t put pressure on your pelvic floor. Swimming and brisk walking are good – but horse-riding and trampolining are definitely out!”

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