Resting metabolic rate increases during pregnancy as a result of increased body mass, pregnancy-associated physiological changes, i.e., cardiac output, and the growing fetus. Physical activity is extremely variable between women and may change over the course of pregnancy.
The basal metabolic rate
The amount of oxygen consumed is an index of the pregnant woman's metabolism when she is at rest—her basal metabolism. The rate begins to rise during the third month of pregnancy and may double the normal rate (+10 percent) by the time of delivery.
They also looked up data on the number of calories women burn while pregnant and lactating. A study from 2005 showed (paywall) they tend to burn roughly twice as many calories as normal.
It can be normal to lose weight in early pregnancy, due to: Morning sickness. In the first trimester, it's common to lose weight as the result of morning sickness. The nausea can diminish your appetite, and the vomiting can cause you to miss out on calories.
Much of the weight gained is extra fluid (water) in the body. This is needed for things like the baby's circulation, the placenta and the amniotic fluid. Medical guidelines used to be quite strict, with recommendations limiting weight gain to a few kilograms.
First trimester weight gain
Remember, most of the weight gain in these early stages is related to the water weight added to your blood. Some women might even lose weight during the first few weeks of pregnancy; this doesn't necessarily mean there's a health problem.
Weight Loss in the First Trimester
A loss of appetite because of the morning sickness is a common cause of pregnancy weight loss too. According to Henderson, it's only a cause for concern if pregnancy weight loss hits 5 and 10 percent of a woman's total body weight.
In the first trimester, most people don't need to gain much weight. This is good news if you're struggling with morning sickness. If you start out at a healthy weight, you need to gain only about 1 to 4 pounds (0.5 to 1.8 kilograms) in the first few months of pregnancy.
The good news: You can take steps to maintain your fitness and keep your core strong while pregnant. In fact, exercising your abs during pregnancy (with your practitioner's go-ahead) has lots of benefits, including reduced risk for back pain and potentially even a speedier labor.
A new study says pregnant women reach the same peak levels of endurance as those competing in Ironman — so the physical intensity of pregnancy is like running a 40-week marathon!
In general, the first trimester (or first three months) does not require any extra calories. Typically, women who begin pregnancy overweight need an additional 200- 400 calories per day during the second trimester (second three months) and an additional 400 calories per day during the third (last) trimester.
If you exercised before your pregnancy, you'll gain less fat weight if you continue to exercise now. But don't expect or try to lose weight by exercising while you're pregnant. In general, the goal is to maintain your fitness level during pregnancy.
Abstract. Maternal metabolism changes substantially during pregnancy. Early gestation can be viewed as an anabolic state in the mother with an increase in maternal fat stores and small increases in insulin sensitivity.
Ovulation speeds up metabolism, thereby increasing the need for energy from food, said Juliette Howe of the U.S. Department of Agriculture's Energy and Protein Nutrition Lab in Beltsville, Md.
Basal metabolic rate varied significantly with the menstrual cycle. Basal metabolic rate decreased at menstruation and fell to its lowest point approximately 1 wk before ovulation subsequently rising until the beginning of the next menstrual period.
According to Dr. Jones from the University of Utah, women who are overweight by 60 pounds (lb) or more may not need to gain weight for a healthy pregnancy. The fetus can use their body's fat stores for energy. By not gaining any weight during pregnancy, a woman will usually be losing fat stores.
Typically, your bump becomes noticeable during your second trimester. Between 16-20 weeks, your body will start showing your baby's growth. For some women, their bump may not be noticeable until the end of the second trimester and even into the third trimester. The second trimester starts in the fourth month.
Your recommended weight gain range for pregnancy will depend on what your body mass index (BMI) was before you became pregnant. The Australian Dietary Guidelines recommend that women who are: at a healthy weight (BMI 18.5-24.9) gain 11.5-16 kg. overweight (BMI 25-29.9) gain 7-11.5 kg.
Some women experience water gain in response to hormones during this time of their cycle. Luteal Phase: The beginning of this phase is relatively uneventful. Any ovulation-related bloat usually vanishes within a few days. But then, a few days later, the PMS-madness begins.
Thicker Thighs and Legs
It can take up to a year to lose the weight gained during pregnancy, says Dr. Dawson. To lose weight gradually, experts recommend a mix of exercise and well-balanced nutrition.
The researchers found that women who gave birth to boys were consuming about 10 percent, or 200, more calories per day than those who went on to bear girls. Yet the amount of weight mothers gained during pregnancy did not differ between those who had girls and those who had boys.
Pregnancy hormones drive this unique pattern of fat accrual. Even worse news? For the average pregnant woman, a fifth or more of the fat she gains goes to her upper thighs.