Getting pregnant is a matter of probability. Sperm plays a huge factor in this probability. Your chances of conceiving "naturally" each month are about 15-20% if:
- The sperm count is higher than 20 million per cc, and
- There are more than 40 million total sperm, and
- You are 35 years or under, and
- Everything else is OK
If he has a low sperm count, your chances of getting pregnant each month are very low, probably less than 5% each month.
With IUI (intrauterine insemination), your chances of getting pregnant with a low sperm count are probably around 10% each month, and with hyperstimulation the conception rate is even higher, probably around 20% or so.
With IVF (in vitro fertilization) and ICSI (Intra Cytoplasmic Sperm Injection) chances of getting pregnant each month are in excess of 40% at most infertility centers.