Kindly see if the following checklist of investigations is done
Husband-
Semen analysis at least 2- done 4 weeks apart preferably in an
infertility center ( examination done by andrologist), Blood sugars
Wife - Blood Sugars,
Thyroid profile, Serum Prolactin- both early morning in empty
stomach at around 6-9 am
Ultrasound scans to evaluate
Uterus , Ovaries & adnexa
Confirm tubal patency- most important- Tube is the connection
between uterus & ovaries( the bridge where sperm meets the egg &
forms a baby) this is size of hair follicle & cannot be seen on scans.
Being such a small opening tube can get blocked easily,
So check with HSG( Xray with dye), or SSG ( Scan with dye) or
Laparoscopy
As you had a baby previously, it only means your ovulation was normal , but tubes can get blocked after the delivery.
If all this done & found normal , nothing can stop a
pregnancy with God's will
If you had baby once, you will surely get baby again
Hope I have cleared your query, do write back if any more queries
All the best
Dr.Balakrishnan