“I know it’s twins,” I said to my husband. Only six weeks pregnant, I could tell this pregnancy was unlike my first two. Like any expectant mother waiting for that first ultrasound, suspicious she might be having twins, I began researching the symptoms I was having, perhaps, like you are doing right now.
Am I having twins?
*Are you over 30?
*Did you conceive with the help of fertility treatments or IVF?
*Women, do twins run on your side of the family?
(Sorry, dads, your twin genes don’t matter for creating your tikes.)
*Are you African-American?
*Are you tall and/or overweight?
*Have you been pregnant several times before?
According to BabyCenter, each of these factors increases your likelihood of having twins or more. 
Twin Pregnancy Symptom #1: Excessive Cramping
Round ligament pain is a common side effect of pregnancy. However, especially if you have experienced a singleton pregnancy, you may notice excessive cramping as your uterus expands to make room for twins.
Twin Pregnancy Symptom #2: Elevated Heart Rate
Many moms pregnant with twins have experienced a noticeable increase in their heart rate. My personal experience was that even at rest, I felt as though I were exercising strenuously. My resting heart rate fell between 95-105 BPM, whereas a normal resting rate for me was around 70-80. For me, this was the biggest clue that I was pregnant with twins, as my body pumped up its blood supply to support two babies.
Twin Pregnancy Symptom #3: Significant Morning Sickness
Morning sickness is a common side effect of pregnancy, however when that morning sickness turns out to be more than an occasional bout of nausea, you may be pregnant with twins. Keep in mind, however, that some women experience excessive morning sickness even with one baby. This is a potentially serious condition known as Hyperemises Gravidarum. 
Twin Pregnancy Symptom #4: High hCG Levels
You will have blood drawn at your first prenatal appointment and one of the tests your doctor will order is to measure your hCG levels. According to the American Pregnancy Association, hCG is a hormone produced in pregnancy that should double every 72 hours during the 8th-11th weeks of pregnancy. 
If your hCG level is high, especially over several tests, there is a chance that you are pregnant with twins.
Twin Pregnancy Symptom #5: Advanced Symptoms
Often, women pregnant with twins will begin experiencing symptoms that don’t normally appear until later on in a pregnancy. This could be any number of symptoms, such as round ligament pain, weight gain and other discomforts. If your symptoms seem to be cropping up much earlier than they should, you could be pregnant with twins.
Twin Pregnancy Symptom #6: Intuition
Don’t discount that inkling you have. If you find that you’re dreaming of twins, or have an inexplicable gut feeling that you’re carrying twins, you could very well be right. That’s exactly what happened in my experience as well!
In the end, the only way to know for sure whether or not you’re pregnant with twins is to wait until your doctor schedules an ultrasound. Don’t be shy to ask for an early ultrasound, if you can’t wait until the routine 20-week measurement ultrasound. Your doctor will likely be more than happy to schedule an early peek, especially if you have significant reason to believe you’re pregnant with twins.
 BabyCenter: Your Likelihood of Having Twins or More
 Help HER: Hyperemises Education Research
 American Pregnancy Association: Human Chorionic Gonadotropin