Pregnancy

Twin pregnancies: Symptoms, risks, and delivery – Medical News Today

Summary

There are two types of twin pregnancy: fraternal and identical. Fraternal twins come from two separate eggs, whereas identical twins come from one egg splitting in two.

Twin pregnancies account for around 3% of all births in the United States. About 70% of those are cases of fraternal, or dizygotic, twins.

People can have more intense pregnancy symptoms with twins. Complications are also more common in twin pregnancies. However, in many cases, people can still h…….

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There are two types of twin pregnancy: fraternal and identical. Fraternal twins come from two separate eggs, whereas identical twins come from one egg splitting in two.

Twin pregnancies account for around 3% of all births in the United States. About 70% of those are cases of fraternal, or dizygotic, twins.

People can have more intense pregnancy symptoms with twins. Complications are also more common in twin pregnancies. However, in many cases, people can still have a vaginal delivery.

This article discusses the types, symptoms, and diagnosis of twin pregnancies. We also explore how maternity care and delivery differ when someone has twins.

There are several ways of classifying twin pregnancies. These include:

  • Monozygotic vs. dizygotic: Monozygotic twins arise from the same zygote, the medical term for a fertilized egg. The zygote splits into two, creating genetically identical twins. Dizygotic twins come from two separate eggs and are not identical — they are no more genetically similar than other siblings.
  • Dichorionic vs. monochorionic: “Chorion” refers to the placenta. Some twins share a placenta, while others do not. Twins that share one placenta are monochorionic, while those that have separate placentas are dichorionic.
  • Monoamniotic vs. diamniotic: These terms describe whether twin fetuses share an amniotic sac or have an individual sac.

The type of twin pregnancy can influence the risk of complications.

A twin pregnancy causes the body to produce higher levels of pregnancy hormones, particularly human chorionic gonadotropin (HCG). This may intensify early pregnancy symptoms.

Some potential signs of a twin pregnancy include:

  • weight gain, especially in early pregnancy
  • increased appetite
  • increased morning sickness
  • more intense symptoms than previous pregnancies or singleton pregnancies
  • feeling distinct fetal movements in different parts of the stomach

An ultrasound can usually diagnose a twin pregnancy. However, ultrasound is not perfect. Rarely, a sonographer may not see a second fetus, especially in early pregnancy.

Blood tests can also help diagnose a twin pregnancy. HCG levels may be higher than usual in early pregnancy if someone has twins.

A second trimester ultrasound can usually determine the sex by looking at the genitals of each developing fetus, but only if they are well-positioned for the ultrasound. Ultrasound sex determination is also sometimes inaccurate.

Twin pregnancies increase the risk of pregnancy and delivery complications. Some common complications include: