Thanks for your ehalth concern.
Duphaston is a progesterone
preparation that is given cyclically to induce regular menstrual bleeding on time each month.
Both the medications have no side effects as such.Irregular periods
will definitely pose fertility issues.
YOU need to consult a gyneologist.
You should have the following done -
1. Thorough internal check up - per vaginum and per speculum.
2. Pelvic ultrasound scan.
3. Hormonal estimations - FSH, LH, AMH, TSh, Prolactin, DHEAs, free testosterone, OGTT, lipid profile
Causes for your problem might include - polycystic ovarian disease
, endometrial damage due to infection, uterine hypoplasia, hypothyroidism
Only after a detailed evaluation, should proper treatment be instituted.