A very good frined of mine has.

Her and hubbie had unexplained infertility and TTC for 8 years and tried everything then moved onto IVF where they had 1 daughter but she passed away at 18 months then they had another daughter by IVF and deided that becasue they have some embryos still frozen to have them transferred and they had another daughter from that. They never used protection after that and fell pragnant when their daughter was 10 months old naturally! She is due to give birth in 2 weeks and is 38 and hubby is 40.

So it can happen