The only scientific way to lose weight is to exercise and eat healthy. After pregnancy, you will need to concentrate ore on exercises of abdomen and thighs. You have to first calculate your basal metabolic rate depending on your lifestyle. There are many BMR calculators available on line. While they are not 100% accurate, they give you a rough idea regarding the number of calories required to maintain your basal metabolic functions. Eating more calories than this can cause weight gain.
If you want to lose weight then you need to consume lesser calories than required for the basal metabolic functions. Also, since you can’t cut down calories drastically, you need to exercise to burn some calories. So if the net calorie consumption is less than need for basal metabolic function and burning of calories is reasonably good, you will start losing weight. You can get many charts online which show you how many calories you burn with a particular exercise. You can use this as rough guideline to help you with an exercise regimen that does not tire you out. These online sites also help you choose from a wide array of food items to build up your calorie need. You have to make a conscious effort to eat 3-4 small well planned meals spread throughout the day. This helps you burn calories better. People who are successful in losing weight and maintaining it are the ones who make lifestyle changes which are acceptable to them, their palate and their working style. To do this you must look for healthier cooking options for meals you love, and slowly cut down on the fat in it so as to not irritate your taste buds much.
Hope this helps. Take care!
The medical advice given should not be considered a substitute for medical care provided by a doctor who can examine you. The advice may not be completely correct for you as the doctor cannot examine you and does not know your complete medical history. Hence this reply to your post should only be considered as a guiding line and you must consult your doctor at the earliest for your medical problem.