11 Things You Didn't Know About Twin Pregnancies

Experts share their advice if you are pregnant with twins.

Medically Reviewed by Melinda Ratini, MS, DO on April 02, 2024
5 min read

If you are expecting twins and wonder what it will be like, many people can relate. That moment when you find out you've got two babies on the way often comes from out of the blue. Although you probably can't fully imagine what it will mean for your day to day life, you can learn a lot before the twins arrive. 

A twin pregnancy is a double blessing, but it can also carry greater risks than singleton pregnancies.

Get to know these things about twin pregnancies from conception through delivery.

We all hear that the older we get, the harder it is to conceive. But it may actually make a twin pregnancy more likely, says Abdulla Al-Khan, MD, the director and chief of maternal and fetal medicine and surgery at Hackensack University Medical Center in New Jersey. "Once you are 25 or into your 30s and 40s, ovulatory cycles are not regular anymore. If you are not regular and do ovulate, you could be ovulating two follicles at the same time." Voila! A twin pregnancy -- without assisted reproductive technologies.

When you're pregnant with twins, you may need more folic acid to help stave off birth defects, says Manju Monga, MD, the Berel Held Professor and the division director of maternal-fetal medicine at the University of Texas Health Sciences Center in Houston.

"We recommend 1 milligram of folic acid per day for twin pregnancies and 0.4 milligrams for singleton pregnancies," says Monga, who has twins. Folic acid is known to reduce risk of neural tube birth defects such as spina bifida.

Twin pregnancies need more monitoring than single pregnancies, Monga says. "We tend to do more frequent ultrasounds for growth in twin pregnancies, compared with one anatomy scan and one growth scan in a singleton pregnancy."

Twins may also have to have twice weekly fetal testing as you get closer to your due date. That may involve more ultrasounds or being placed on the fetal heart rate monitor for the testing.

"One of the things that is postulated as causing morning sickness is high levels of human chorionic gonadotropin, and we know that levels of this hormone are higher in twin pregnancies, so women carrying twins have a higher incidence of nausea and vomiting in the first trimester," says Al-Khan. The good news? Most morning sickness abates within 12 to 14 weeks of pregnancy -- even in twin pregnancies.

That's not all, Monga says. Women pregnant with twins complain of more back pain, sleeping difficulties, and heartburn than those who are carrying one child. Being pregnant with twins also carries a higher rate of maternal anemia and a higher rate of postpartum hemorrhage (bleeding) after delivery.

"When you spot in the first trimester, you could be undergoing a miscarriage, and miscarriages are more common in mothers of twins, triplets, and quadruplets -- so we see more spotting in first trimester with multiples," Al-Khan says.

If you do have spotting, don't panic. "A little spotting in the absence of cramps is reassuring, but when you are cramping, passing clots, and actively bleeding, that is a sign that's something is happening" and you should seek medical advice right away.

"Generally when you are pregnant with twins, fetal movements become more noticeable at weeks 18 through 20 of pregnancy, and the same is true in singleton pregnancies," Al-Khan says.

When you begin to feel fetal movements actually depends on whether this is your first pregnancy. "If you have been pregnant before, you know what fetal movement is, but if you are pregnant for the first time, you really can't distinguish the movement from gastrointestinal activity."

"With twins, mothers gain more weight as there are two babies, two placentas, and more amniotic fluid," says Al-Khan. "You also need more calories for twin pregnancies."

Still, there is not a well-established formula for weight gain during twin pregnancies, says Monga. "The average weight gain is 25 pounds for singleton pregnancy and 30-35 pounds for twins. We don't want moms pregnant with twins to gain more than 40 [pounds] or less than 15 pounds."

The Institute of Medicine's provisional guidelines for weight gain in women expecting twins say:

  • Women of normal weight should aim to gain 37-54 pounds
  • Overweight women should aim to gain 31-50 pounds
  • Obese women should aim to gain 25-42 pounds

Exactly how much weight should you gain? The IOM recommends that you talk to your health care provider about that, because every pregnancy is unique.

"The gestational diabetes risk is higher in twin pregnancy," says Monga. She notes that gestational diabetes can mean having larger babies and needing a C-section delivery -- but twins tend not to be big babies. Still, developing gestational diabetes during pregnancy also makes you more likely to develop type 2 diabetes later in life, she says.

"People really don't know what causes preeclampsia to start, but we know it occurs more frequently in twin pregnancies," Monga says. Preeclampsia is marked by high blood pressure, protein in the urine, and sometimes swelling in the feet, legs, and hands. It is the precursor to the more serious, potentially fatal eclampsia.

Most women carrying twins go into labor at 36 to 37 weeks, as opposed to 40 in a single pregnancy, Al-Khan says, and some may go even earlier. "Generally, if the twins are born after 34 weeks, there should not be a major concern, but a premature baby is still a premature baby," Al-Khan says. "Twins are at higher risk of preterm labor and delivery and have higher degree of respiratory issues."

As a result of being born too early, twins may be born at low birth weights, and such babies tend to have more health problems than babies born weighing more than 5.5 pounds.

Unfortunately, there is no evidence that bed rest alone prevents preterm labor or delivery in twin pregnancies, and the use of agents to stop preterm labor have not been proven to be effective either, he says. "Stopping premature labor is challenging in multiple gestations."

"The likelihood of having a C-section is absolutely higher in twin pregnancies," Al-Khan says. "There is also a higher incidence of the baby being in breech position among twins than singletons." When the baby is in a breech position, a C-section delivery is usually required.