Normal weight during pregnancy

Pregnancy inevitably comes with weight gain, which is completely normal and necessary from a physiological standpoint. However, it is important to understand that it is not only the total number of kilos gained that matters, but also their distribution in the woman's body. The normal weight gain depends on many individual factors.

Main factors influencing weight gain

One of the main indicators for determining acceptable weight gain is the body mass index (BMI) before pregnancy. Underweight women need to gain more weight to ensure the normal development of the fetus, while overweight women should be more moderate to avoid complications. BMI is calculated using the following formula: weight in kilograms divided by height in meters squared.

Weight gain standards according to BMI:

• BMI < 18.5 — 12 to 18 kg
• BMI 18.5 to 25 — 11 to 16 kg
• BMI 25 to 30 — 7 to 11 kg
• BMI > 30 — 5 to 9 kg

In addition to BMI, the age of the expectant mother (under 25 years, metabolism is faster; over 35 years, it is slower), the presence of a multiple pregnancy, general health status, presence of chronic diseases, and the psycho-emotional context that can influence appetite are also taken into account.

Particularities of natural conception and IVF

The mode of conception can influence weight gain. In the case of natural pregnancy, standard norms are applied based on BMI, age, and general health status of the woman. In the case of in vitro fertilization (IVF), weight gain may be more significant due to hormonal support before and after embryo transfer.

Women who have undergone IVF are often monitored more closely by their doctors, and their weight gain is observed particularly carefully. In the case of multiple pregnancies, especially in older women, weight gain may exceed the norms of natural conception. In such cases, the attending physician provides individual recommendations based on the specifics of hormonal treatment and the IVF protocol.

Weight gain progression by trimester

The first trimester (1 to 13 weeks) is characterized by minimal weight gain: about 1 to 2 kg, especially if the woman suffers from preeclampsia. During the second trimester (14 to 26 weeks), fetal growth accelerates, blood volume and amniotic fluid volume increase, and weight can increase by 300 to 500 g per week. In the third trimester (27 to 40 weeks), the pace slows down, and the average weight gain is about 1 kg per month.

Approximate total weight gain:

• 1st trimester: 0.5 to 2 kg
• 2nd trimester: 5 to 8 kg
• 3rd trimester: 3 to 6 kg
• Total: 10 to 15 kg

Distribution of additional weight

Weight gain includes:

• Fetus: 3 to 4 kg
• Placenta: 500 to 700 g
• Amniotic fluid: 1 to 1.5 kg
• Increase in blood volume and fluids: up to 2 kg
• Stored fats (energy reserve for mother and fetus): 2 to 3 kg
• Growth of the uterus: 1 to 2 kg
• Increase in breast gland volume: up to 1 kg

Weight control during pregnancy

It is best to weigh oneself in the morning on an empty stomach, in the same clothes, and on the same scale. During the first trimester, weighing once a month is sufficient; starting from the second trimester, it is advisable to monitor weight weekly. Keeping a weight journal is useful, where you record the date, your current weight, changes compared to previous values, and your overall health status.

When to consult a doctor?

A consultation is necessary in the following cases:

• Rapid weight gain (more than 1 to 1.5 kg in 1 to 2 weeks)
• Insufficient weight gain or weight loss
• Appearance of edema, headaches, hypertension, urinary disorders

Risks of abnormal weight gain

In the case of excessive weight gain:

• Gestational diabetes
• Preeclampsia
• Increased risk of cesarean section

In the case of insufficient weight gain:

• Delayed fetal development
• Deficiency in vitamins and minerals
• Premature birth
• Risk of miscarriage

The role of diet in weight control

A balanced diet includes 5 to 6 meals a day in small portions, without excess. The basis of the diet should consist of:

• Proteins: meat, fish, eggs, legumes
• Complex carbohydrates: vegetables, fruits, whole grains
• Healthy fats: nuts, fatty fish, vegetable oils

It is important to include calcium and vitamin D, folic acid, and iron. Consumption of fast food, fried and very salty dishes, soft drinks, caffeine, and alcohol is discouraged.

Physical activity and safety

Moderate physical activity is beneficial and safe in the case of a normal pregnancy. Recommendations:

• Outdoor walking
• Swimming or aqua aerobics
• Yoga or Pilates for pregnant women
• Stationary cycling at a moderate pace

Contraindications: risk of miscarriage, severe toxemia, bleeding, placenta previa, severe anemia, severe hypertension. It is always necessary to consult your doctor beforehand.

Emotional health and attitude towards body changes

The psycho-emotional state is just as important as physical health. Support from a partner, family, consultations with a psychologist, breathing exercises, and walks outdoors help manage anxiety. It is useful to perceive body changes as a manifestation of care for the baby, rather than as an aesthetic problem.

Weight control during pregnancy after an IVF protocol at NatuVitro clinic

A pregnancy that occurs after an in vitro fertilization procedure at the NatuVitro IVF clinic in Barcelona requires particularly careful monitoring of the woman's condition, including the evolution of her weight. Due to the use of hormonal treatment and the specifics of preparing for embryo transfer, weight gain may begin earlier and be more significant than in a spontaneous pregnancy.

At NatuVitro, we provide comprehensive follow-up for patients at all stages of pregnancy, including regular assessments of weight, metabolic status, and hormone levels. The clinic's specialists develop individual recommendations regarding diet, physical activity, and medical follow-up, taking into account the history of infertility, response to ovarian stimulation, presence of chronic diseases, and psycho-emotional context.

Weight control is particularly important for older patients, women with polycystic ovary syndrome, thyroid function disorders, or those who were overweight before pregnancy. In these cases, weight gain is strictly monitored to minimize the risks of gestational diabetes, hypertension, and preeclampsia.

Thus, at the NatuVitro clinic, weight control is an integral part of the management strategy for pregnancy after IVF and plays a key role in the successful course of pregnancy and the birth of a healthy child.

Gradual recovery after childbirth

After childbirth, a woman loses 5 to 7 kg, and then her weight gradually decreases. The diet should remain balanced, especially during breastfeeding (2000 to 2500 kcal per day). Moderate physical activity is possible 6 to 8 weeks after childbirth. Breastfeeding accelerates metabolism and helps the body recover more quickly.

Regular follow-up with a doctor during pregnancy allows for monitoring weight gain and timely reacting to any abnormalities, thereby ensuring the health of both mother and child.