The hyponatremia is caused by a relatively smaller loss in total body water. 1  any cause of hypovolemia such as prolonged vomiting, decreased oral intake, severe diarrhea. 2  diuretic use (due to the diuretic causing a volume depleted state and thence ADH release, and not a direct result of diuretic-induced urine sodium loss)
Biotin is safe but is not likely to do much to help your hair grow unless you are deficient in biotin, which is uncommon. A reasonable dose is 5 mg. However, you may get better results by taking a quality multivitamin, eating a healthy diet rich in organic fruits and vegetables, avoid junk food and getting adequate sleep.
Some experts have suggested a widespread use of biotin supplements for pregnant women. However, there is not enough research supporting this recommendation. The daily AI recommendation for pregnant women of all ages is 30 mcg per day. A higher AI of 35 mcg is recommended for lactating women.