After spending approximately 40 weeks inside the womb, the average newborn weighs 7 1/2 pounds. Most babies weigh between 5 1/2 and 10 pounds. The average length of a newborn is 20 inches (50 centimeters), with a range of 18 to 22 inches. The average head circumference (the distance around the head) is 14 inches (35 centimeters).
Lactobacillus and Bifidobacterium are the most common probiotic bacteria. The Lactobacillus genus has 18 different bacteria strains, while the Bifidobacterium genus consists of eight strains.
âProbiotics have been consumed by humans in one form or another for more than 100 years,â Dr. Lucak says. Today the two most common types of probiotics found on the market are species of good bacteria called Lactobacillus and Bifidobacterium. While their manufacturers claim that probiotics have a number of overall and digestive health benefits, the jury is still out on who should take them.