When you're pregnant, there is an increase of hormones and blood flow, which can make your skin super sensitive. So when your hair grows back, even after a wax, swelling and discomfort is more likely. You may also be more prone to getting ingrown hairs because of the onset of skin sensitivity brought about by pregnancy.
Here's a website with suggestions of home remedies for ingrown hairs. Most of them involve the use of food products like fruits so I reckon they are pregnancy-safe (except for the aspirin remedy, might want to skip that):
http://www.homeremedyhacks.com/24-splendid-home-remedies-to-get-rid-of-ingrown-hair/
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