Researchers recommend that mothers-to-be not gain more than 3t 11lb during pregnancy in order to lower the chance of her baby becoming sick.

  • Wuhan University researchers analyzed data about 15.8 Million pregnancies in the United States.
  • These experts set out to calculate the optimal weight gain for each starting BMI. 
  • Higher BMI women should be discouraged from losing or maintaining weight
  • They should instead aim to be less bloated during pregnancy, according to the team.
  • For example, mildly obese women should look to gain only 18–35 lbs (8–16 kg)

Pregnant women with normal to underweight bodies mass index (BMI), should aim for a weight gain of no more than 3t 11lb (24kg) during pregnancy. This will prevent their baby from getting sick.

Researchers led from Wuhan University studied data on 15.8 million pregnancies to determine the optimum amount of weight mothers-to-be should put on.

Based on their findings, they have recommended that women with higher BMIs not be encouraged to maintain or lose weight during pregnancy — but to gain less.

For example, the team have concluded that the ideal weight gain for mildly obese women during pregnancy is 18–35 lbs (8–16 kg).

Expectant mothers with a normal or underweight body mass index (BMI) should look to gain no more than 3st 11lb (24 kg) while pregnant so their baby doesn't get sick, a study has found

A study found that pregnant mothers who have a normal to underweight body weight index (BMI), should aim for a gain of no more than 3t11lb (24kg) during pregnancy. This will prevent their baby from getting sick.

Huijun Chen (Zhongnan Hospital Wuhan University) and other colleagues carried out the investigation.

The researchers stated that “adverse pregnancy outcomes” are often associated with improper gestational fat gain in their paper.

“Inadequate gestational growth increases the risk of preterm births and being born too small for gestational life.

“Excessive gestational fat gain” is associated with pregnancy complications like gestational hypertension. [high blood pressure] and diabetes, caesarean delivery, postpartum weight retention and obesity in later life.’

Meanwhile, they added, excessive weight gain can lead to such ‘adverse outcomes to the offspring such as being born large for gestational age, macrosomia, and childhood obesity.’

In their study, the researchers analysed health data on some 15.8 million mother–infant pairs as recorded in the US National Center for Health Statistics database.

This team focused only on births that occurred within the term. They compared each mothers BMI and weight gain to determine if there were any significant health concerns or deaths in their offspring.

Health issues deemed significant included admission to intensive care for any reason, records of seizures and any need for therapy or assisted ventilation. 

The researchers found that, for women who were underweight or normal weight at the start of their pregnancy, the ideal weight gain ranged from 1st 12.5lb to 3st 11lb (12–24 kilograms).

Overweight women were recommended to gain between 22–53 lbs (10–24 kg), mildly obese women 18–35 lbs (8–16 kg) and the most obese 13–22 lbs (6–10 kg). 

According to the team, these results suggest that pregnant women who have been overweight before becoming pregnant shouldn’t be encouraged or encouraged not to lose or maintain weight.

Full results of this study have been published in JAMA Network Open.


The weight gain during pregnancy is variable. The majority of pregnant women gain between 10kg to 112.5kg (22lb and 26lb), with the bulk of their weight gaining after week 20.

While your baby will gain a lot of weight, your body will store fat to produce breast milk once your baby is born.

Obesity can cause health problems in you and your unborn child.

Too much weight

Overweight can lead to poor health and high blood pressure.

However, pregnancy is not the right time for a diet as this could harm the child’s health.

You should eat healthy.

An excessive weight gain can lead to complications.

They include:

  • gestational diabetes:Gestational diabetes is when you have too much sugar (glucose) in your blood. It can increase your chances of having a big baby.
  • pre-eclampsia:Pre-eclampsia can start with a rising blood pressure. Although most cases are not serious and don’t cause any problems, this can indicate that there is something wrong.

Losing too much weight

A baby born at a lower birth weight than 2.5kg (or 5.5 lb) can have problems.

You may also notice that you aren’t burning enough calories.

Your diet and your weight before becoming pregnant can play a role in your weight loss.

Some naturally thin women are able to stay trim while pregnant, and still have healthy children.

Active living

Being active during pregnancy is crucial as your body will be ready for labour.

Unless your GP or midwife advises you to stop exercising, continue your daily activities.

Information about how to lose weight

You may get special advice from your doctor or midwife if you’re overweight:

  • Over 100kg, or 15.5st
  • Below 50kg (8st)

Talk to your GP or your midwife if your concerns are about weight and other health aspects while you’re pregnant.