I ran accross a good question about someone concerned with DEET use in pregnancy. This is a very good question and a pregnant woman should always be aware of what she is doing and taking, with respect to the health of her baby. By the way, the article was over at BootsnAll Travel Health Forum.
DEET is safe for use by pregnant and breast feeding women, following manufacturer guidelines. CMAJ • August 5, 2003; 169 (3) “DEET-based insect repellents: safety implications for children and pregnant and lactating women” by: Gideon Koren, Doreen Matsui and Benoit Bailey.
Another fantastic article on Mosquito Bite prevention can be found here: Mosquitoes and Mosquito Repellents: A Clinician’s Guide by Mark S. Fradin, MD. This article is in Annals of Internal Medicine, 1 June 1998 | Volume 128 Issue 11 | Pages 931-940.
These are my two main sources when I need to refer about safety of mosquito repellents.
There are a few other options, as well. Avon Skin-so-soft lotion has some anti-mozzi effects and is well tolerated in children and adults. The downside to this is that it requires more frequent applications for decent protection. The anti-mosquito properties are believed to come from either fragrance of the cream or the chemicals it contains, benzophenone and diisopropyl adipate. Citronella oil should aslo be mentioned, although it is not proven to be as effective as DEET.
DEET is a very well know compound and has a wide safety profile. The few reported adverse events associated with DEET have largely been in pediatric populations and associated with improper use (using far too much and too often). For more information you can visit another post on mosquito bite prevention.