We were trying but not trying (ie not charting, doing OPKs etc) for six months with no success. I started doing Ovulation Predictor Kit testing to determine when I ovulated and in December fell pregnant when we BD'd the day we got the first +OPK result (due to work, stress etc we didnt do it any other time that month!). Unfortunately we had a missed m/c in February and then after one AF we fell pregnant again in March by doing the same thing - BD'ing the day of the first OPK result (although we BD'd every second day for 9 days before that too!).

The other thing was getting DH to take zinc tablets as well as multivitamins.

Good luck to your sister!