We've had a surge in inquiries in the last three months from pregnant women wanting to know if they had to surrender the family guinea pig(s) before the pregnancy proceeded any further.
This likely stems (somehow) from the prevailing concern about pregnant women and cats, due to the risk of exposure to toxoplasmosis. (By the way, if you or someone you know is pregnant and has a cat, you might want to read this info from Yale before you take Kitty to a cat rescue.)
We've checked with the vets at South Wilton Veterinary Group and Pieper Olsen Veterinary Hospital -- as well as several OB-GYNs in southern Connecticut -- and the consensus is that pregnant women have no need to be concerned about being around guinea pigs.
They added that if women still have residual concerns, basic common-sense hygiene practices -- washing one's hands, keeping cages clean, and so forth -- should lay those concerns to rest. If all else fails, have husbands (and/or older children) clean Piggy's cage during the pregnancy and -- while they're at it -- Kitty's litter box.