Our fourth pregnancy was a pleasant surprise. But learning that we would have twins was, honestly, overwhelming. When staring at the first ultrasound of those two perfect blebs, it’s hard to imagine the miracles that our bodies are capable of. But is there a way to know if you are carrying multiples before the ultrasound? Are there early signs that you are pregnant with twins? Yes and no. What’s different about a multiple gestation pregnancy?
Twins and Higher-Order Multiples
A conception that results in a twin or more pregnancy is extraordinary. Twin pregnancies can result from the fertilization of multiple eggs or from a lucky fertilized egg that splits just days after conception.2
Monozygotic or identical twins come from one fertilized egg by one sperm that has split in two. Identical twins are always the same sex and have the same set of genes or DNA. Dizygotic or fraternal twins result from two separate eggs being fertilized by two individual sperms. Genetically, fraternal twins are no different than siblings born of other pregnancies who share half of the same genetic material.2
Higher-order multiples like triplets, quadruplets, or more can combine fraternal and identical babies.
What Are My Chances of Having Twins?
Twin births represent about 3% of all births in the United States. Approximately 70% of twins are fraternal without assistive reproductive technology (ART) or ovulation-inducing medication.1
ART, such as in vitro fertilization and ovulation-inducing medications, has increased the rate of twins and higher-order multiples such as triplets and quadruplets. These practices often have a 30-35% chance of resulting in twinning.3
What Are the Signs and Symptoms of a Twin Pregnancy?
You may wonder about the difference between single pregnancy and twin pregnancy symptoms. Many pregnant people experience different symptoms between these types of pregnancies. Here are the early signs you’re having twins:
1. Elevated hCG
Levels of hCG vary greatly from person to person. Typically, hCG levels for twins are significantly higher.4
Human chorionic gonadotropin (hCG) is a hormone released by the embryonic tissue destined to become the placenta. In the early weeks, this hormone is responsible for maintaining pregnancy and is detectable in urine and blood. Levels of this hormone rapidly increase with each passing week of early pregnancy and peak around 10 weeks.5 However, high levels of hCG are not a confirmation of twin or multiples pregnancy. Only an ultrasound can positively identify twins.
2. Intense Nausea and Vomiting
The exact cause of nausea and vomiting in early pregnancy is not fully understood, but it is generally accepted that the hormone hCG is the culprit.6 This tell-tale sign of pregnancy affects up to 80% of pregnant people. Because hCG levels are higher in twin and other multiple gestation pregnancies, nausea and vomiting may also be worse. Carrying multiple babies also increases the risk for hyperemesis gravidarum or extreme nausea and vomiting, which can negatively impact the pregnant parent.7
3. Rapid Weight Gain
Double the babies, double the weight gain? Not quite, but nearly so. Weight gain of 25 to 54 pounds, depending on pre-pregnancy BMI (body mass index), is considered appropriate when carrying multiples.1 Fundal height, or the belly size measured from the pubic bone to the top of the uterus, will grow much faster as the uterus expands to house two or more babies.8 Parents who are pregnant with twins will be reaching for those maternity clothes much sooner!
When Do Twins Show Up on an Ultrasound?
Ultrasound evaluation offers a definitive diagnosis of twin pregnancy. Twins or other multiples are visible on transvaginal ultrasound at four to five weeks gestation.8 It is also possible to determine if the twins are identical or fraternal. Around eight weeks of pregnancy, an ultrasound can determine if each baby lives within its amniotic sac, an essential factor for growth, development, and survival.8 It is possible to receive a diagnosis before twin pregnancy symptoms even begin.
Can Twins Cause a False Negative Pregnancy Test?
Pregnancy tests screen for the presence of hCG in urine. Home pregnancy tests are highly reliable and offer fast results. Occasionally, a false negative result occurs if a test is taken too soon after conception.12
False negatives can also occur in the case of a twin or multiples pregnancy. The concentration of hCG can be very high, causing an oversaturation of hormones for the antibodies of a urine pregnancy test to detect.12
How Is Prenatal Care Different With a Twin or Multiples Pregnancy?
Prenatal care with twins or multiples generally means more appointments and monitoring to ensure those little ones grow well. Standard pregnancy testing is recommended, but it is not as sensitive in pregnancy with multiples. Prenatal care visits will be more frequent than with a singleton baby, especially in the third trimester.10
One of the most significant determinants for increased ultrasound monitoring or other testing of twins is whether the babies have their own placenta and amniotic sac. Dizygotic pregnancies have enough placenta and amniotic sacs to go around. Identical or monozygotic pregnancies share a placenta and, in rare cases, an amniotic sac.9
Monozygotic twins are at an increased risk for complications like discordant growth and twin-to-twin transfusion syndrome.9 Frequent ultrasounds monitor the health and development of the babies. A fetal echocardiogram at 22 weeks is also recommended because of the increased risk of cardiac anomalies in monozygotic twins.1 It is safe to say that attending appointments in some twin pregnancies can feel like a part-time job!
Risks of a Multiples Pregnancy
Unfortunately, growing more than one baby at one time does come with the potential for complications and risks, including an increased risk of:3
Growing, birthing, and raising twins or more can feel daunting. There is double (or more!) the baths, the diapers, the bottles, the laundry, etc. But those extra blessings also come with double the smiles, laughs, and joy. Parents of multiples are specially chosen.