Before prenatal ultrasounds and lab tests became common, women had to rely on symptoms such as excessive nausea, weight gain, early fetal movement and fatigue to determine if they would be dealing with two newborns instead of one. Additionally, twins are more common in some families, according to the American College of Obstetricians and Gynecologists, but a woman over 30 is more likely to have a twin pregnancy.
Fatigue is one of the most common symptoms of a twin pregnancy. Although most pregnant women have greater fatigue and less energy than before pregnancy, excessive fatigue is often one of the first signs of a twin pregnancy, reports the Family Education website. A woman who has already had at least one pregnancy is more likely to notice this symptom, since she has a basis for comparison. As the pregnancy progresses, the fatigue continues instead of getting better, possibly because of sleep deprivation. A May 2008 study from the American Academy of Sleep Medicine found that by the end of the pregnancy, 70 percent of women expecting twins got less than six hours of sleep in a 24-hour period -- instead of the recommended seven to eight hours -- and the sleep was of low quality.
Severe Nausea and Vomiting
Another sign of a twin pregnancy is excessive morning sickness. A woman who is constantly sick -- or who has severe nausea and vomiting -- is more likely to be carrying twins, according to the American Pregnancy Association. Severe morning sickness could be a condition called hyperemesis gravidarum, which is more common in women carrying twins, according to the Hyperemesis Education and Research Foundation. Hyperemesis gravidarum can cause excessive weight loss, dehydration and other potentially serious problems for the mother. A woman who has severe morning sickness should consult her doctor.
Physical Signs Don't Match a Singleton Pregnancy
Women who are carrying twins sometimes gain more weight -- or start to gain weight earlier in the pregnancy than a woman carrying only one fetus, according to Family Education. When the doctor or midwife measures the size of the uterus, a woman with twins is often found to be “large for gestational age,” which means the uterus is bigger than would be expected for a pregnancy with one fetus. Some women report feeling movement as early as the first trimester, which is less common in a pregnancy with one fetus. Other factors can also cause these symptoms, but early fetal movement may indicate twins in some women. Sometimes, the doctor or midwife can hear two heartbeats late in the first trimester.
Tests That Confirm a Twin Pregnancy
Lab tests and other diagnostic methods also help determine a twin pregnancy, according to Family Education. An ultrasound is the definitive method, as doctors can clearly see two fetuses when they perform the ultrasound. One of the earliest tests is a measurement of the human chorionic gonadotropin -- or HCG -- levels in the woman’s body. HCG is a hormone the fertilized egg secretes that helps regulate pregnancy; normally, it increases during the first trimester and then stabilizes. In a single pregnancy, normal HCG levels range from 300 to 600 by the 33rd day after a woman’s last menstrual period. In a twin pregnancy, however, the range is from 200 to 1,800 at 33 days. If the HCG level is on the high end of the range, it can signal a twin pregnancy and the test should be repeated at 36 to 40 days to confirm the possibility of twins. If you think you might be carrying twins, contact your doctor or midwife.