I haven't taken the exam yet, but I would imagine that they are not going to have you do Leopolds or anything (and definitely no pelvic/breast exams). Given those limitations, I think the OB/GYN stuff ought to be pretty straightforward.
Just remember that the non-prenatal-care aspects of OB/GYN are all about pain and bleeding. So there's pregnant pain (with or without bleeding) and non-pregnant pain (with or without bleeding). Pregnant bleeding (with or without pain), and non-pregnant bleeding (with or without pain). That's what I suspect we will see. If pregnancy is involved in our cases it will likely be first trimester bleeding in an undiagnosed pregnancy rather than something like premature labor, incompetent cervix, abruption or a previa.
Your history just needs to take those things into account, and then get a good OB/GYN history. Adjust PE accordingly ... probably want to do basic Thyroid, CV/Pulm/Abd/Ext as a baseline and then add ENT/lymph/neuro/psych elements as needed. They aren't looking to see if you can come up with the world's best DDX, they want to know if your H&P is consistent with the DDX that you do produce. So, for example, hypothyroidism might not really be the highest on an expert's list, but if you do think it might be hypothyroidism, you probably want to ask related questions, examine the thyroid, and know to order a TSH and a Free T4. The nice thing is that for OB/GYN cases you know that there are a lot of cases where you would likely do breast/pelvic/rectal/genital exams and you will also be getting a B-hCG... so theres most of the "tests" you'll be ordering right there.
The only other tricky OB/GYN aspects might involve counseling about birth control or STDs/high risk behavior, and partner abuse. I guess we'll see how it goes.