The rule of thumb is most women need about 300 extra calories every day during the last five to six months of pregnancy for good fetal development. This will combine to a healthy weight gain of about one pound each week.
In general, the brain can withstand up to three to six minutes without oxygen before brain damage occurs, but this may vary from person to person.If the brain goes without oxygen longer than this, serious and often irreversible damage is likely to take place.eath is usually declared once the brain has gone more than 15 minutes without oxygen. Although the brain can only go a few minutes without oxygen before some type of brain damage occurs, patients can often regain cognitive function if treated quickly.
Between 30-180 seconds of oxygen deprivation, you may lose consciousness. At the one-minute mark, brain cells begin dying. At three minutes, neurons suffer more extensive damage, and lasting brain damage becomes more likely. At five minutes, death becomes imminent. At 10 minutes, even if the brain remains alive, a coma and lasting brain damage are almost inevitable. At 15 minutes, survival becomes nearly impossible. There are, of course, exceptions to every rule. Some training routines help the body make more efficient use of oxygen, enabling the brain to go longer periods without this vital element. Free divers routinely train to go long periods without oxygen, and the current record holder held his breath for 22 minutes without sustaining brain damage!