Has anyone had to take anticoagulants during pregnancy?

I'm not pregnant, but my husband and I are going to start ttc soon. I saw my gynecologist today for my annual check up and she told me that I would have to take Lovenex or Heparin (blood thinner shots) during my pregnancy. I had a blood clot last year caused by a reaction to birth control pills and she said it can happen again during my pregnancy. She says it won't affect the baby and I've done research all afternoon which confirms it, but I'm still worried about the effects on the baby. I know that both drugs have been approved for use on pregnancy, but it just seems unbelievable that something being injected into me would have no effect on the baby. It is making me reconsider even ttc. I could never live with myself if it caused some complication for the baby. I'd really like to know some personal experiences. Have you or anyone you know taken blood thinners during pregnancy? If so did you or the baby experience any complications?