Is it normal to lose weight in the first trimester
It is more conventional for women to gain weight during pregnancy, as their baby develops over the months. However, it is also quite normal to lose some weight, especially during the first trimester , as your body adjusts with all the changes related to pregnancy. Although common and often harmless, weight loss in early pregnancy is still not considered a sign that you are carrying.
Causes of weight loss during pregnancy
Losing weight during the first trimester is commonly due to morning sickness  that often makes you too nauseated to have a normal appetite, preventing you from following the recommended diet. Severe morning sickness may lead to a condition called hyperemesis gravidarum (HG), another, more serious but rarer factor causing weight loss during this time .
The main reason behind gaining weight during pregnancy is to form a fat deposit for providing the energy required during labor, delivery and later for breastfeeding . For this reason, it is not unusual for obese women to lose some weight during this period as they already have sufficient amount of these energy resources in their body. If you are overweight and are unable to modify your diet, then the calories stored in your body will be utilized for your baby’s nutritional requirements, resulting in weight loss .
Can you stop losing weight while pregnant
There is not much to worry about if you are losing a little weight early in the pregnancy. Most women gradually regain their appetite by the second trimester. However, you can take some of the following measures to manage nausea and improve your appetite to make sure your baby is not deprived of his necessary nutrients:
- Consulting your doctor for a prenatal vitamin with low iron dosages as it is less likely to trigger nausea, allowing you to follow a healthier diet [1, 5, 6].
- Trying to eat your regular meals and taking occasional snacks – even if you don’t feel like eating – to get the necessary nutrients .
- Having vitamin-B6 rich foods, such as avocados, whole grains, bananas, brown rice, nuts, and certain fishes, as these can help to reduce nausea, allowing you to have a better appetite .
- Keeping the morning sickness in control as far as possible by keeping yourself hydrated [6, 13] and practicing some relaxation techniques and yoga to reduce stress [1, 7].
If you are already past the 13th-14th weeks and are equally put off by the smell of most things edible, there is nothing to worry about too much. You can just follow the same diet and supplements as the first trimester, and your baby will be fine .
Dieting while pregnant: Is it safe
It is never recommended to follow a weight loss diet when pregnant as this will prevent you from getting the essential vitamins and minerals including folic acid, iron, calcium, and magnesium. You are supposed to get around 2500 calories per day during pregnancy to ensure proper fetal growth , which might be a little difficult to get if you are dieting.
Malnutrition during these nine months can come in the way of proper development of your baby, also increasing the risks of various maternal complications [3, 10].
Overweight and pregnant
Although being overweight is associated with an increased risk of high blood pressure, gestational diabetes, and pre-eclampsia, dieting is not recommended even in obese women . Moreover, if you are overweight at the time of conceiving, losing a little weight over the pregnancy does not reduce these health risks much .
Tips for healthy weight loss to manage obesity
- Exercising more frequently (consult your doctor about your work-out schedule as exercising too often might be harmful to the baby)
- Following a diet containing low-glycemic index carbohydrate-rich foods like baked beans, porridge, wholemeal bread, fresh fruits, and vegetables, as the body takes more time to break down these carbs, releasing energy slowly, thus making you feel full for a longer time 
- Using healthier sweeteners like honey instead of those sugar cubes
When to call the doctor
If you fail to gain the recommended weight by the third trimester, consult your doctor for a proper diet to help you gain the necessary pounds .
In case the severe morning sickness persists even in the late second trimester, or you continue to lose weight after the 25th week of pregnancy, it might indicate some underlying condition. Rapid weight loss or losing weight despite following a proper diet any time during these nine months may indicate serious complications like gestational diabetes . Hyperemesis gravidarum often needs medical attention .[ref]
- https://www.nlm.nih.gov/medlineplus/ency/article/001499.htm [/ref]