Weight gain during pregnancy is a process due to the growth of the fetus, but also to water retention and the accumulation of maternal fat tissue
Weight gain in pregnancy: how many pounds should you gain? And based on the quarter how much should be increased? What is the right weight distribution? What if you are unable to eat in early pregnancy due to nausea (and therefore lose weight)? What if we start from an overweight situation?
In this article
Weight gain in pregnancy: what is it?
Weight gain is a normal process throughout pregnancy, and is due to the growth of the fetus and the structures that contain it, but also to water retention and the accumulation of maternal adipose tissue.
The causes can be found in the metabolism individual of the patient and in the diet followed. However, although eating habits remain a fundamental aspect in maintaining a good state of health (it is important, for example, not to overdo the quantities of meals, despite the belief in the need to eat “for two”), recent studies show that the factor principal able to determine weight gain in pregnancy is the starting weight.
How to check weight in pregnancy
The best way to control pregnancy weight gain is weigh yourself once a week, choosing:
- the same day,
- more or less at the same time,
- wearing the same amount of clothes (or no clothes),
- and always on the same scale.
It is not worth weighing yourself more often or at other times of the day because you will have daily fluid variations.
If once a week is too much, you can decide to weigh yourself twice a month.
Body mass index
Weight gain at the end of pregnancy must be related to the indice of maternal body mass (Body Mass Index, which is obtained dividing the weight by the square of the height = kg / m2): if underweight, a woman will need to gain more than an overweight woman. While maternal weight should remain almost unchanged throughout the first trimester, an average increase of no more than 2 kilograms per month is recommended after the 20th week, for a total of 11-16 kg.
A summary scheme based on the indications of the American Institute of Medicine, in collaboration with the National Research Council:
- Increase indicated in starting conditions of underweight: 12.5-18 kg
- Increase indicated in starting conditions of normal weight: 11.5-16 kg
- Increase indicated in starting conditions of overweight: 7-11.5 kg
- Increase indicated in starting conditions of obesity: 5-9 kg
Weight gain when expecting twins
Women who have one twin or multiple pregnancy they have to calculate more kilos for each child. According to the opinion of several gynecologists, if you are expecting twins, you should usually gain 16-24 kg throughout the pregnancy. The weight varies a lot depending on the woman’s build. For the recommended weight, it is best to hear from the specialist following you.
There are no official guidelines for women expecting three children. The doctor will define the reference weight.
How weight gain is distributed
At the end of pregnancy, here is roughly how the weight is distributed if you increase by about 14 kg:
- 3.3 kg child
- 0.7 kg placenta
- 1 kg of amniotic fluid
- 1 kg uterine expansion
- 1 kg maternal breasts
- 2 kg maternal blood volume
- 2 kg of liquid in the maternal tissue
- 3 kg maternal fat
Weight gain: how much
How much weight to take depending on the trimester of pregnancy
Here are the indications if you start from a normal weight situation.
- First trimester of pregnancy: there is no need to eat for two and weight gain should be minimal. A milestone could be around 1 and 2 kg, although many women sometimes lose weight due to nausea and morning sickness. Others exceed this value, because they often try to fight nausea with starchy, high-calorie foods.
- Second trimester of pregnancy: the baby begins to grow more and more and you too will gain in total 5-7 kg.
- Third trimester of pregnancy: about 0.5 kg per week with a net increase of 3.5-4.5 kg.
Institute of Medicine and National Research Council offer an indication of how much weight (approximately) it would be appropriate to take week after week in particular in the second and third quarter, again according to the starting conditions:
- underweight: 440-580 grams;
- normal weight: 350-500 grams;
- overweight: 230-330 grams;
- obesity: 170-270 grams.
In reality this is not a perfect pattern to follow, the important thing is that the increase is slow and steady, both for you and for your baby.
Too little or too much weight gain: the risks
Gaining too much or too little weight during pregnancy carries different health risks for the patient and the unborn child.
A overweight increases the risk of complications such as gestational diabetes, cardiovascular disease, preeclampsia, fetal macrosomia (when the full-term fetus is estimated to weigh more than 4.5 kg), difficulty in childbirth and resorting to caesarean section. Furthermore, an obese mother has a one in three chance of having a baby it will in turn develop obesity problems.
Underweight women, on the other hand, are at risk of having a preterm birth or one poor fetal growth, which will lead the baby to be born too small (which increases the chances of incurring metabolic, cardiovascular or respiratory complications).
SOURCES: National Center of Biotechnology Information; JAMA
The lights to watch out for
Be careful if in the second and third trimester of pregnancy you gain weight quickly and suddenly, especially if you experience swelling in your legs, feet, face or hands. Contact your doctor right away.
Be careful even if you do not gain weight for more than two consecutive weeks in the period from the fourth to the eighth month (unless your doctor has prescribed a diet for you).