The answer is nausea or anorexia. Development of the fetus is important, so nausea and anorexia that would inhibit with the young woman’s nutrition would root the most damage to the developing fetus. It could also lead to electrolyte disproportion if she did not take in sufficient fluid. While sleeplessness could cause difficulties long term, this side effect could be alleviated through adjustment of the dosing time (earlier in the day), by reducing the dosage to her former 20 mg daily, or by altering to every other day dosing of 40 mg, since fluoxetine has a long half-life. Headaches are painful but can be treated with mild painkillers or other actions, such as cold cloths, that would not damage the fetus.