As in my case, elevated levels of the hormone hCG (human chorionic gonadotropin) in the blood may indicate that you're pregnant with twins. If these numbers seem to spike in an early test, you could be having more than one baby -- but it's not definitive. read more
If placental analysis doesn't solve the mystery, you can order an at-home DNA test for about $100 and get results in one to two weeks (or pay $400 for results in three days). Identical twins almost always have identical DNA, while fraternal twins share about 50 percent of their DNA. read more
Prior pregnancy: You have a greater chance of becoming pregnant with twins with subsequent pregnancies than with the first. Ultrasound Confirmation If you have any early symptoms or signs of a possible twin pregnancy or any factors that increase your chance, discuss this with your doctor or midwife. read more