Is it ok to have a mammogram if i just found out i was pregnant? say approx 4 weeks?

Indication?: The most dangerous period for radiation is during organogenesis, which occurs in the first trimester when organs are forming. If the mammogram is indicated, then benefits outweigh risks. If mammogram is elective, wait until 2nd trimester or wait until post-partum (though then you'll likely be breastfeeding). If you need the imaging, definitely get it. Ultrasound or MRI are other imaging types.

XRAY Radiation: Nope. Not at all. I doubt that any doctor, including the radiologist, would want to put your baby through this risk at such an early stage in their development.

Why?: Is there a lump that was detected on physical exam? If so, then an ultrasound would be done. If there was felt to be a need to do a mammo, your abdomen could be effectively shielded. Mammos use lower energy x rays which would not penetrate very far into your body even without shielding so with shielding exposure to the fetus should not be an issue.

Mammogram: There is essentially no excess radiation exposure to the fetus during a mammogram. However, you probably don't need to begin having screening mammograms yet, and if you have a lump or other symptom, ultrasound would be the first imaging study of choice.