Just the thought of a rectal thermometer can make a new mother squirm. But rectal-temperature readings are the most accurate, and -- in the first three months of life, when a fever is considered a medical emergency -- "you need to be on the money," says Vincent Iannelli, M.D., author of The Everything Father's First-Year Book, available in May 2005.
But have no fear, an easier way to take a rectal temperature is here: First, lubricate the tip of a digital rectal thermometer with petroleum jelly. Place your baby on his back on the changing table, lift his legs like you're changing his diaper, and slide the thermometer about a half inch into the rectum. Moms who use this method say it's much easier than placing the baby on his stomach. More good news: After the first three months, you can use an underarm, ear, or pacifier thermometer (just tell the doctor which you used).