Gaining weight during pregnancy is normal and healthy, but excess weight can lead to obesity later in life. In one study, 256 pregnant women in the first trimester received dietary counseling plus daily probiotics or a placebo, or a placebo with no counseling, through the end of exclusive breastfeeding, up to six months after giving birth. The probiotics were Lactobacillus rhamnosus and Bifidobacterium lactis.
At the end of the study, about half the women who took a placebo had a waist size of 31.5 inches or larger compared to 26 percent for the probiotics group. Excess weight, particularly around the waist in women, raises chances for disease, and doctors recommend levels below 35 inches.