The Pregnancy Weight Gain Calculator will help you determine the recommended weight gain that will promote a healthy pregnancy.
If you started your pregnancy at a healthy weight, by the time you give birth, you will have gained between 25 and 35 pounds, and probably only 7 to 8 pounds of that will be the baby itself.
What accounts for the extra pregnancy weight gain? Everything from amniotic fluid (2 pounds) to an increased blood supply (4 pounds). Keeping your pregnancy weight gain in check can be a challenge.
How much weight should I gain during pregnancy?
The amount of pregnancy weight you’re recommended to gain depends on where you started: underweight, at a healthy weight, overweight, or obese (and whether you’re carrying twins or multiples).
This tool will calculate your pre-pregnancy BMI (body mass index), give you a recommendation for pregnancy weight gain, and generate a pregnancy weight gain chart to show how you’re tracking toward your target weight range.
But keep in mind that your recommended weight gain may be different depending on your health needs and any pregnancy complications. Especially if you’re overweight, obese, or underweight, it’s important to talk to your doctor or midwife and use pregnancy weight gain information that’s customized for you.
Changes in the body during pregnancy
Is your period late? Do you have morning sickness? Do you feel tired most of the time? If you are answering Yes to those questions, it means that you are probably pregnant. Congratulations!
Usually, pregnancy lasts 40 weeks from the last menstrual period or 38 weeks from fertilization (but it is generally counted from the last menstrual period). Pregnancy is typically divided into three trimesters:
- trimester – first 12 weeks
- trimester – from 13th till 28th week
- trimester – from the 29th week till childbirth
A lot of women feel fear about pregnancy and the changes it causes to their bodies. They are afraid of stretch marks, urinary infections, pain, and going through labor.
There is even a medical term, tokophobia, which is an unspecified phobic anxiety disorder classified by the International Classification of Diseases! But these are not the only changes that occur to the body of a pregnant woman.
There are specific breast changes (they are larger and the areolae are darker), significant changes in hormone regulation, the arterial pressure lowers (due to dilatation of vessels by progesterone), cardiac output increases by 30-50%, heart rate increases by 25%, blood volume increases by even 45%, as well as vital capacity. All these changes have three major reasons:
- To enable appropriate growth for the baby;
- To prepare for the labor, and
- To prepare for breastfeeding after childbirth.
It is also worth remembering and knowing that although pregnancy is not a disease, it may predispose the woman to certain conditions. These include tooth decay, urinary and other infections, heartburn, constipation, hemorrhoids, cholelithiasis, hypertension, etc.
And last but not least, there is a change in a pregnant woman’s weight!
Why do you gain weight during pregnancy?
Pregnancy can lead to changes in many of your daily routines and habits, including what you eat and how much exercise you get. But most of all, women’s bodies change during pregnancy to ensure that their unborn child gets enough food and other things they need.
These changes already start happening in early pregnancy and become more and more noticeable as time goes on. Women gain more weight in the final months of pregnancy than they do in the first few months (look at the pregnancy weight gain timeline generated by our calculator).
There are various reasons women gain weight during pregnancy, and many different body areas where they gain it. First, of course, is the baby itself. Then there are the changes to your body that support your pregnancy and what will happen after childbirth.
You gain fat, which your body is going to use to store nutrients for breastfeeding; your breasts increase (and this is also additional weight!), and you gain weight from your enlarged uterus, placenta, and amniotic fluid. The rest of your weight gain comes from the increased blood and body fluids.
Pregnancy weight gain by week and by trimester
In pregnancy, the ideal weight is different than in non-pregnant women. Are you wondering how much weight you should gain during pregnancy? Or maybe you think it is a fixed number of pounds or a fixed percentage of your pre-pregnancy weight?
Let’s check the truth! Pregnancy weight gain depends on two main factors: your pre-pregnancy BMI and the type of pregnancy (singleton or twin).
- If you were underweight (BMI below 18.5), you should gain between 28 and 40 pounds during your pregnancy.
- If your BMI was normal (18.5–24.9), you should gain between 25 and 35 pounds (and 37 to 54 pounds if you’re carrying twins).
- If you were overweight (BMI between 25 and 29.9), you should gain between 15 and 25 pounds (and 31 to 50 pounds for a twin pregnancy).
- Finally, if you were obese before the pregnancy (BMI over 30), you should gain between 11 and 20 pounds (25 to 42 pounds during a twin pregnancy).
This weight gain is your target for the 40th week. During your pregnancy, however, you can and even should monitor the changes in your weight as well. The Institute of Medicine of the National Academies suggests a distribution of pregnancy weight gain by week; we built this calculator according to their guidelines so you can check whether your weight is in the recommended range.
During the first trimester, you will probably gain 3-4 pounds in total only – your baby is still tiny, and morning sickness may prevent you from gaining any weight at all.
Most of your weight gain will occur during the second trimester. In the third, even though you will still keep gaining weight, the increase will slow down, especially during the ninth month.
Use our pregnancy weight gain calculator to receive the full information about typical weight gain in pregnancy, tailored for you.
How to use the pregnancy weight calculator?
Check these few steps to find your healthy weight gain during pregnancy:
- Enter your height and pre-pregnancy weight into the appropriate boxes.
- The pregnancy weight gain calculator will automatically determine your pre-pregnancy BMI.
- Mark whether you are expecting twins or not – this will heavily influence your weight gain.
- Choose the week of pregnancy.
- The pregnancy weight gain calculator will determine the minimum and maximum recommended weight gain since the beginning of pregnancy – these values are approved by the Institute of Medicine of the National Academies. It will also add these values to your initial weight.
You can also take a look at the graph below the pregnancy weight calculator on the left. Thanks to it, you can also check how much weight you should gain in a particular week of pregnancy and how much it should change over time.
How to weigh yourself?
First of all, don’t stress too much – in pregnancy, you don’t have to weigh yourself every day. The day-to-day fluctuations, often caused by a big dinner the day before, can really drive you crazy. It’s enough to weigh yourself once a week.
Remember always to do it at the same time of the day, wearing the same amount of clothes, and using the same scale. Later, you can check your measurements on the timeline graph below our pregnancy weight calculator to ensure that you are doing well.
What if I gain too much or too little weight?
Don’t fret if your weight differs from the recommended one only slightly. Your pregnancy will, most likely, not follow the “ideal” weight gain distribution. As soon as you approach your target weight, you should be fine. Watch out for the following, though, as they might be some worrying signals:
- gaining more than three pounds in one week of the second trimester;
- gaining more than two pounds in one week of the third semester;
- gaining no weight at all for more than two weeks in a row during months 4 – 8.
Women who gain a lot of weight in pregnancy have a higher risk of specific health problems and complications during childbirth. For instance, they are more likely to have a hefty baby with a birth weight of over 4,000 g or 4,500 g (macrosomia) and are more likely to need a Cesarean section.
They are also more likely to have difficulties losing the extra weight after giving birth. Gaining too much weight might also cause other problems, from simple discomfort and back pain to trouble reading the ultrasound results, and even preeclampsia (gestational hypertension plus proteinuria) and premature labor.
On the other hand, if a woman doesn’t gain enough weight and doesn’t get enough different foods in pregnancy, it can harm her growing baby: babies are then often born too early (preterm birth) or often weigh too little at birth.
Gaining too little weight may be even more dangerous for the baby, as we realize that small, premature infants have more problems in the neonatal intensive care units.
If you are in any of the situations mentioned above, don’t forget to consult your doctor!