Thanks for writing in.
You have had two spontaneous pregnancies in last 6 months, which indicates absolutely a normal fertility
for a couple despite your slightly prolonged cycles & your husbands semen report.
Remember only only one sperm is required for a pregnancy
& 15 million are good enough!
IF you thyroid
hormone levels are ok you don't have to worry about this problem.
I suggest you to start taking folic acid
supplements, improve your diet & general health & hope for the best.
Best of luck.