Why am I under weight?

Hi Annyia,
A few questions for you:
1. How are you trying to gain weight? Is this under the supervision of a health care provider (Registered Dietitian, for instance), or as part of a recommendation from your doctor?
2. Are you regularly seen by a health care provider, such as your GYN for annual exams (and also seen by a nurse who checks your blood pressure, weight, etc)?
3. Do you have any physical symptoms (sleeplessness, loss of menstrual period, low energy, hunger, sudden/rapid weight loss) that are causing you concern?
4. Do you have any emotional symptoms/concerns (fear of gaining weight, not enjoying food, avoiding situations with food, extreme exercising)?
5. Are you currently breastfeeding any of your children?

There are many different indicators regarding if a woman is within a healthy weight range or not:
1. BMI (Body Mass Index). A healthy weight BMI is between 18.5-24.9. Your BMI is 18.4, and this does put you, just barely, in the "underweight" category.
2. Physical symptoms (of problematic low weight): low blood pressure, low heart rate, loss of menstrual period, low energy, low mood, bone loss
3. Emotional symptoms (of problematic low weight): fearful of gaining weight, avoiding food or certain foods, rigid eating and/or exercising

I hope to hear back from you, as I am curious if you have been medically evaluated for your weight, since you have been "underweight" most of your life? Being "big boned" or "small boned" is not really a factor in weight. The most extreme cases of being underweight (anorexia) does pose many health risks, but it sounds like you are just wondering why you are different physiologically than the rest of your family? Please let us know if you do have any of the symptoms mentioned above, and we can provide further information.