I wanted to add that my story is similar to yours - children were 24, 22, 19 & 15 - I had no idea about how fertility plummets after age 42 - good luck to you - jen
I agree w/everthing Yvette said and wanted to add that now's the time to be seeing a fertility specialist (reproductive endocrinologist) so he/she can run some tests and get an idea what your egg quality is & go over any options. I doubt that IUI's or IVF's w/your own eggs are an option though.
There are some women on this forum who've gotten pregnant in their mid 40's but it's really a matter of finding that "golden" egg which is more difficult at age 43. I too ended up getting pregnant via donor eggs (at age 44), & delivered a year ago last April a healthy baby boy.
Your eggs in your 40s become of poor quality. Poor quality eggs turn in to miscarriages. Many times it's difficult to even get pregnant in your 40s. And many times IF you do get pregnant you end up miscarrying. I think the miscarriage rate increases with age and i think that it's about 50% or higher.
Unfortunately you are fighting against mother nature when you try to conceive in your 40s. Not to say that it isn;t possible because it certainly is, but you will have to fight very hard to get pregnant and harder to sustain the pregnancy. I'm not sure, but perhaps an infertilty doctor might be able to help you our or check your hormones to see how your egg supply is doing.
Now I bet you are thinking...oh I have my period every month and it's every 28 days. I thought that meant something too, but bottom line is the quality of your eggs. And at about your age the quality isn't that great. Unfortunately your infertility will decease dramatically after you hit 30s and it just gets worse from that point.
Like I said it is possible to get pregnant, but I think you are going to have a hard time a 43 even though you'll be 43 in august. I am not trying to be insensitive, it's just the way that it is. I am 42 and will be 43 in June. I have had five miscarriages over the past two and half years. We gave up using my eggs and used donor eggs to get a better chance of a take home baby.