Healthy Weight Gain During Pregnancy: What Is Normal?

Weight gain during pregnancy is normal and necessary. Your baby is growing, your uterus and breasts enlarge, your blood volume increases, and your body stores extra nutrients to support pregnancy and breastfeeding after birth.

However, many pregnant women worry: “Am I gaining too much?” “Am I gaining too little?” “Is my baby growing well?” The answer depends mainly on your pre-pregnancy body mass index, also known as BMI, whether you are carrying one baby or twins, and your individual medical situation.

Healthy pregnancy weight gain is not about “eating for two”. It is about gaining enough weight to support your baby’s development while reducing the risk of complications such as gestational diabetes, high blood pressure, a very large baby or poor fetal growth.

How Much Weight Gain Is Normal During Pregnancy?

The most widely used pregnancy weight gain recommendations are based on pre-pregnancy BMI. The Centers for Disease Control and Prevention uses these recommended ranges for women pregnant with one baby: [1]

These are general ranges. Your doctor or gynae may advise a different target if you have twins, gestational diabetes, high blood pressure, severe nausea and vomiting, a history of low-birth-weight baby, or other medical concerns.

How to Calculate Your Pre-Pregnancy BMI

BMI is calculated using your weight before pregnancy and your height:

BMI = weight in kg ÷ height in metres ÷ height in metres

For example, if your pre-pregnancy weight was 60 kg and your height is 1.60 m:

60 ÷ 1.60 ÷ 1.60 = 23.4

This falls within the normal weight BMI range of 18.5 to 24.9. For a woman pregnant with one baby, the general recommended total weight gain would be about 11.5 to 16 kg.

How Much Weight Should You Gain by Trimester?

Weight gain is usually not the same throughout pregnancy. Many women gain little weight in the first trimester, especially if they have morning sickness.

First trimester

For many pregnant women, weight gain in the first trimester is modest. The Institute of Medicine guidelines assume about 0.5 to 2 kg total weight gain during the first trimester for all BMI groups. [2]

Some women may gain less, and some may even lose a little weight due to nausea and vomiting. If you cannot keep food or fluids down, are losing weight significantly, or feel weak and dehydrated, speak to your doctor.

Second and third trimester

Weight gain usually becomes more noticeable from the second trimester onwards as the baby, placenta, uterus, blood volume and body stores increase.

General weekly weight gain after the first trimester may be roughly:

• Underweight before pregnancy: about 0.5 kg per week
• Normal weight before pregnancy: about 0.4 kg per week
• Overweight before pregnancy: about 0.3 kg per week
• Obese before pregnancy: about 0.2 kg per week

Do not worry if your weight does not increase perfectly every week. Doctors usually look at the overall pattern together with your baby’s growth, blood pressure, urine tests and other pregnancy checks.

Where Does Pregnancy Weight Gain Go?

Pregnancy weight gain is not just the baby’s weight. It also includes changes in the mother’s body that support the pregnancy.

• Baby
• Placenta
• Amniotic fluid
• Increased blood volume
• Enlarged uterus
• Breast tissue
• Extra fluid
• Maternal fat and nutrient stores

This is why healthy weight gain is expected even if the baby may weigh only around 2.5 to 4 kg at birth.

What If You Gain Too Little Weight?

Gaining too little weight may increase the risk of having a baby who is smaller than expected or born with low birth weight. It may also suggest that the mother is not getting enough calories, protein or key nutrients, or that nausea, vomiting, stress or illness is affecting intake.

Speak to your doctor if:

• You are losing weight after the first trimester
• You cannot eat properly due to nausea, vomiting or food aversion
• You feel weak, dizzy or dehydrated
• Your baby is measuring small
• Your doctor is concerned about fetal growth

If you need to gain more weight, the goal is not to eat more sugary or fried foods. Instead, focus on nutrient-dense foods such as whole grains, lean protein, eggs, milk, yoghurt, cheese, nuts, avocado, beans, tofu, fish that is safe in pregnancy, and healthy snacks between meals.

What If You Gain Too Much Weight?

Gaining more than the recommended range may increase the risk of complications such as gestational diabetes, high blood pressure, a larger baby, delivery complications and more difficulty losing weight after birth. ACOG notes that obesity in pregnancy is linked with higher risks such as gestational diabetes, high blood pressure, preeclampsia and cesarean birth. [3]

Speak to your doctor if:

• You are gaining weight very quickly
• You have sudden swelling of the face or hands
• You have high blood pressure
• You have gestational diabetes
• Your baby is measuring much larger than expected
• You are unsure whether your diet is balanced

Do not try to lose weight during pregnancy unless specifically advised and supervised by your doctor. Pregnancy is not the time for crash dieting, detox plans, slimming pills or extreme carbohydrate restriction.

Sudden Weight Gain: When Should You Be Concerned?

Gradual weight gain is expected. However, sudden weight gain together with swelling, headache, visual changes, upper abdominal pain or high blood pressure can be a warning sign of preeclampsia and should be assessed urgently.

Seek medical advice promptly if you notice:

• Sudden swelling of the face, hands or around the eyes
• Severe headache
• Blurred vision or seeing spots
• Pain in the upper right abdomen
• Shortness of breath
• Sudden rapid weight gain over a short period

Do Pregnant Women Need Extra Calories?

Pregnant women do not usually need many extra calories in the first trimester. Energy needs increase later in pregnancy, but the exact amount depends on pre-pregnancy weight, activity level, medical condition and whether the mother is carrying one baby or multiples.

A practical approach is to focus on food quality rather than simply eating more. Choose meals that include:

• Whole grains or other healthy carbohydrates
• Protein such as fish, chicken, lean meat, eggs, tofu, beans or lentils
• Vegetables and fruit
• Calcium-rich foods such as milk, yoghurt, cheese, fortified soy milk or calcium-set tofu
• Healthy fats from nuts, seeds, avocado or suitable fish

HealthHub Singapore encourages healthy eating patterns and physical activity during pregnancy, and provides pregnancy resources covering antenatal care, nutrition and exercise. [4]

Singapore-Friendly Tips for Healthy Pregnancy Weight Gain

1. Build a balanced plate

For many local meals, try to include vegetables, protein and a reasonable portion of carbohydrates. For example:

• Fish soup with rice, plus extra vegetables
• Yong tau foo with vegetables, tofu and less fried items
• Economic rice with one protein, two vegetables and less gravy
• Brown rice bee hoon or wholegrain noodles when available
• Home-cooked porridge with egg, fish, minced meat or tofu and vegetables

2. Watch sweet drinks

Bubble tea, sweetened coffee, fruit juice, soft drinks and dessert drinks can add a lot of sugar without keeping you full. Choose water, unsweetened milk, reduced-sugar soy milk or less-sweet drinks more often.

3. Choose snacks that support pregnancy nutrition

Useful snack ideas include:

• Wholemeal bread with peanut butter
• Plain yoghurt with fruit
• Cheese with wholegrain crackers
• A boiled egg
• Nuts in small portions
• Fruit with milk or fortified soy milk
• Steamed sweet potato

4. Do not skip protein

Protein supports the growth of the baby, placenta and maternal tissues. Include protein at meals where possible, such as eggs, fish, chicken, tofu, beans, lentils, lean meat, milk or yoghurt.

5. Stay active if your doctor says it is safe

Physical activity can support healthy weight gain, reduce pregnancy discomfort and improve wellbeing. HealthHub notes that the second trimester is often a good time to begin or continue exercise because risks and discomfort may be lower, but pregnant women should follow medical advice and avoid unsafe activities. [5]

Common pregnancy-friendly activities include walking, swimming and prenatal exercise classes. Avoid activities with a high risk of falling, abdominal injury or overheating.

What About Weight Gain for Twin Pregnancy?

Women carrying twins usually need to gain more weight than women carrying one baby. CDC provides different recommended ranges for twin pregnancy based on pre-pregnancy BMI. For example, women with normal pre-pregnancy BMI carrying twins are generally advised to gain more than those carrying one baby. [1]

If you are carrying twins or more, ask your gynae for a personalised weight gain target and nutrition plan.

How Often Should You Weigh Yourself?

Your weight is usually checked during antenatal visits. Some women may also weigh themselves at home once a week. Try to weigh yourself at a similar time of day, using the same scale, and avoid checking too often if it makes you anxious.

Remember: one number on the scale does not tell the whole story. Your healthcare provider will also consider your blood pressure, urine results, blood tests, baby’s growth, ultrasound findings and your overall health.

When to Speak to Your Doctor or Gynae

Speak to your doctor or gynae if:

• You are not sure what weight gain range is right for you
• You are gaining much faster or slower than expected
• You have severe morning sickness or vomiting
• You have gestational diabetes or high blood pressure
• You have a history of eating disorder or strong anxiety about weight
• You are carrying twins or more
• Your baby is measuring small or large

If you feel guilty or stressed about weight gain, tell your healthcare provider. Pregnancy weight can be emotionally sensitive, and support should be practical, respectful and non-judgmental.

FAQ: Healthy Weight Gain During Pregnancy

How much weight should I gain during pregnancy?

It depends on your pre-pregnancy BMI. For one baby, general recommendations are 12.5 to 18 kg if underweight, 11.5 to 16 kg if normal weight, 7 to 11.5 kg if overweight, and 5 to 9 kg if obese.

Is it normal not to gain much weight in the first trimester?

Yes. Many women gain little weight in the first trimester, especially if they have morning sickness. The general first-trimester gain is about 0.5 to 2 kg, but some women may gain less. Speak to your doctor if you are losing weight significantly or cannot keep fluids down.

Do I need to eat for two during pregnancy?

No. Pregnancy does not mean doubling your food intake. Focus on balanced meals, enough protein, healthy carbohydrates, vegetables, fruit, calcium-rich foods and suitable healthy fats.

Can gaining too much weight harm the baby?

Excessive pregnancy weight gain may increase the risk of gestational diabetes, high blood pressure, a larger baby and delivery complications. Speak to your doctor if you are gaining weight very quickly.

Can gaining too little weight harm the baby?

Too little weight gain may increase the risk of poor fetal growth or low birth weight. If you are not gaining enough, your doctor may review your diet, symptoms and baby’s growth.

Should I diet during pregnancy if I am overweight?

Do not start crash diets, slimming pills or detox plans during pregnancy. If you were overweight before pregnancy, your doctor can help you aim for a safe and appropriate weight gain range.

Is sudden weight gain normal in pregnancy?

Gradual weight gain is normal. Sudden rapid weight gain, especially with swelling, headache, visual changes or high blood pressure, should be checked urgently because it may be linked to preeclampsia.

Key Takeaway

Healthy weight gain during pregnancy depends on your pre-pregnancy BMI, whether you are carrying one baby or multiples, and your overall health. For many women pregnant with one baby, the recommended total weight gain ranges from about 5 kg to 18 kg depending on BMI.

Rather than focusing only on the number on the scale, aim for steady weight gain, balanced meals, safe physical activity and regular antenatal checks. If your weight gain is much faster or slower than expected, or if you feel worried, speak to your gynae or doctor for personalised advice.

References

• [1] Centers for Disease Control and Prevention, Weight Gain During Pregnancy.
• [2] Institute of Medicine / National Academies guidelines on gestational weight gain, as summarised in medical literature.
• [3] American College of Obstetricians and Gynecologists, Obesity and Pregnancy.
• [4] HealthHub Singapore, Healthy Start For Your Pregnancy.
• [5] HealthHub Singapore, Being Fit When Pregnant.