Dear Madam, Hi & Welcome. Delayed periods is not caused by Folic acid. Folic acid is routinely prescribed during IVF treatment to prevent open neural tube defects like spina bifida if your partner conceives. It does not delay the period. Since your period is delayed by one week and started having symptoms which could be due to an early pregnancy. So apart from pregnancy, hormonal imbalance, mental stress, obesity, irregular diet habits, certain underlying medical illness, pelvic infection etc can also cause delayed period. You should undergo home pregnancy test at the earliest to rule out pregnancy if you are sexually active and consult with doctor following the test. Hope the advice given above would be useful.