I built cedar furniture for years. I sprayed polyurethane 5-8 hours every week. Some mild respiratory problems would occur right after spraying that would last through the night, but never anything permanent. If you wear a simple surgical of dust mask it will catch any of the particulates that cause the problems. The aroma isn't pleasant but that won't harm you except in your case, it may cause some nausea

All Volatile Organic Compounds (VOC) pose a certain risk. VOCs are present in the solvents that are used to liquify the plastics in polyurethane and for other oil based finishes.

I understand and don't want to minimize your concerns, but I think you and your baby are safe because you aren't breathing the densest fumes which are present where the finishes are being applied and for the short period after evaporation begins until the VOCs are dispersed.

One thing to remember is that you can SMELL only a few molecules of the solvents, but it isn't the smell that causes problems.

I predict that you and your baby will be happy and healthy with no bad effects from your brief exposures.

My floors are being redone with oil polyurethane. I'm 13 weeks pregnant. I'm not sleeping in the house but have had a few hours exposure each day these past 3 days (just running in the house to get items, folding laundry, going to the restroom, taking a shower) maybe totaling 10 hours total exposure time. Today I had to run in for about 5 minutes because the floor guys didn't leave any of the windows open to facilitate it airing out. I know prolonged poly exposure can cause brain damage problems and is not good for pregnant women to breathe in. I guess I just wondering people's past experiences with fairly minimal exposure who didn't end up with babies with birth defects and brain damage. :(