While there are no hard and fast guidelines, most pregnant women should decrease what they were able to lift before pregnancy by about 25 percent.
Many pregnant women with other children wonder if picking them up will harm their developing baby. The good news is that lifting has not been linked to concerns with premature birth or the growth of your baby. The most common issue is sustaining an injury as your center of gravity shifts, and you may be more unsteady on your feet. In addition, the hormones of pregnancy can make you more prone to joint injuries since they are more lax in pregnancy.
While most safe estimates tell women to not lift anything more than about 25 pounds, this is a broad generalization. If your child is 30 pounds, lifting him or her up is most likely fine as long as you have a low risk pregnancy and do so wisely (that is, lift with your knees, and stop the activity if you feel fatigued or uncomfortable).