BD timing question

I usually ovulate on day 21, but am at a fertility clinic (7 months ttc after miscarriage and d & c) and today an ultrasound showed I will probably ovulate in 4 days (day 18). I had planned to do frequent bd through o and start tonight (have abstained for weeks), for 8 days, but now it would only be 4. Should I start that tonight or should I just do 1 attempt at pos opk ? (How many days before o would that be?? I am not using opks anymore because I spent way too much on them, so will just go by the ultrasound results-I am going everyday now. ) Should I bd once when they tell me I will ovulate the next day? It's my husband's bday in 3 days, so may not be able to avoid bd that day....
I have not been getting pregnant with cut off or 0+12 and got pregnant twice he first time:) I just want to get pg so my son can have a sibling and so I can stop this diet and enjoy life again!
THANKS!!!!!~!!!

I really think we are seeing best results for both pink and conception with doing one attempt at positive OPK. (one day before ovulation)

We have not been getting as good of results with frequent BD thru O and you don't have enough time for that anyway. Frequent BD thru O only works if you are able to have 7-10 releases before the earliest day you could possibly get pregnant and 4 days before ovulation, you can already get pregnant from that!

Normally I do not recommend abstaining for weeks, but the die is cast now and I think you have to just go with that because it's already done and cannot be changed at this point. To do anything but continue abstain, I think will only hurt your sway.

Thanks so much!!! I'm sure my husband's been releasing, but I just havent fel into it because it's become a chore lately....and I was saving up to bd every night! Will try once the day before o....isnt that total boy territory though? That makes me nervous!

If you're not comfortable with it, then don't do it. But several of us have gotten girls with that timing after 2,3,4, or more boy opposites with Shettles girl timing.

The scientific case against Shettles is here. http://genderdreaming.com/forum/gend...le-timing.html

THANKS SO MUCH for taking the time to reply:) One more question-why is the day before o better than o for one attempt? I'm not going to try 0+12...it didn't work for me and I just want to get pg. After a missed miscarriage and trouble conceiving after, gender is becoming less important, but I HAVE always wanted a daughter":)

I think it is because the sperms can take up to 12 hours to reach the egg, and they need to be there hen the egg comes!
So therefore O-1 or the day of pos OPK will give best chance of conception.
Sperms can survive up to 5 days in female repro track, so some people even get PG doing O-5.