The dosage of Saheli Pill for contraceiption is different from that of PCOD. For effective contraception, Saheli Pill should be taken twice a week for first three months, followed by once a week, till contraception is desired.
In your case you have taken only one pill a week from the second month onwards, which wont be sufficient to ensure contractiption. In fact there are multiple pregnancies (twins or triplets) reported in the first three months of treatment of Saheli, if the dosages is not followed properly.
The reason behind is, Saheli does two actions on the female reproductive system.
One is, it promotes ovulation (realease of egg from ovary)
and Two, thinning of the inner wall of uterus, this is very important for the embryo to implant and grow (to put it simple, inner wall of uterus should be thick enough for successful pregnancy)
So Saheli pill on one hand promotes fertility (desired in PCOD treatment) and in the other hand discourages successful pregancy (desired in Contraception), the deciding factor is the duration and dosage of treatment.
So precisely to answer your question, since you are taking Saheli for PCOD and trying to become pregnant, the changes of pregnancy is more.
Congrats...
Also, We strongly suggest to take a pregnancy test after your missed periods and consult your Gynaecologist.