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Twin Pregnancy

How You Get Pregnant With Twins


Updated May 16, 2014

Identical twin baby boys (3-6 months) lying side by side, portrait
Niki Mareschal/Photographer's Choice/Getty Images

People are very fascinated with twins and other multiples. It seems mysterious how one pregnancy can result in more than one baby.

Multiple pregnancies are on the rise in recent years with more and more twins and other types of multiples being born. The majority of the reason for this rise is the increased use of fertility drugs.

How Twins Are Made

There are a couple of ways that multiples are conceived:

  • Multiple eggs are released or there is more than one ovulation. Both (or more) eggs are fertilized and you have fraternal twins. This can happen with or without fertility drugs.

  • One egg is release but splits in two. Identical twins are made. This can happen with or without fertility drugs.

  • In cases of IVF, there are usually 3 or more fertilized eggs put back into the uterus. The rationale is that not all of these will implant, though sometimes they do.

Once conceived you have a lot of possibilities on placentas, implantation locations, number of amniotic sacs. For example, you can have two babies, two placentas, and two sacs. You can have two babies one placenta, two sacs. It will be important to know exactly what you are dealing with, particularly when it comes to amniotic sacs.

How Multiples Are Discovered

Many people learn about their multiples at an early ultrasound. Although some critics say that before twelve weeks gestation there is still a high risk of Vanishing Twin Syndrome (VTS), where one baby stops growing and is either absorbed back into the mother's body or is still born when the other twin is born.

Some people find a rapid rate of grow in their uterus which leads some to suspect twins. I will say, for all of you second timers out there, that your bellies will grow faster than with your first pregnancy, so don't automatically assume twins.

Sometimes multiple heart beats are heard, leading your practitioner to believe that there is more than one bundle of joy in your uterus.

Some women find out when they have abnormally high levels on the AFP test that multiples are on the way, since multiple babies would increase the levels of these hormones. It's also sometimes possible to detect multiples with serial hCG levels in early pregnancy. The more babies the faster the rate of rise in the hCG which should nearly double every 48 hours with a singleton.

About 3% of all twin pregnancies are undetected until birth. It is possible to have an ultrasound and not see the other baby, though rare.

Multiple Pregnancy

Being pregnant with multiples is not necessarily a high risk situation, except when dealing with higher order multiples or specific problems. Someone on the bulletin board phrased it as being "high need." I really think that this is a positive shift away from the technical side. Find a practitioner who is experienced with multiples births, but one who will not panic at every corner.

In general you need to increase the amount of protein that you eat. Protein is the building block of every cell in your body and your babies' bodies. It will help you build a good placenta and a strong amniotic sac. A healthful diet will also help fight against infection.

You will probably see your practitioner more frequently towards the end of pregnancy. You may have more testing than most women during pregnancy, but not always. Some of these might include: non-stress testing, more ultrasounds, etc.


There can be a higher risk for complications. You will be monitored for the normal complications of pregnancy like high blood pressure, and fetal growth. However, twins and other multiples can have higher incidences of things such as Intrauterine Growth Restriction (IUGR), Twin to Twin Transfusion (TTTS), and others. Remember to keep your appointments, watch your diet and do your Fetal Kick Counts.

Multiple Birth

In years past cesarean became popular for multiple births. Now that rate is about 50% for twins, and declining. We've found that vaginal birth is usually very safe for multiples, who frequently need the stimulation and rise in hormones levels associated with labor.

Whether or not you will have a vaginal birth will depend on many factors, including the position of the babies, and how the babies tolerate labor.

If your babies are in a position where neither can move, they are said to be locked. These babies will have to be born via cesarean.

Breech babies really depend on the size of the baby and the skill of the practitioner. Usually if Baby A (The first baby in the pelvis.) is head down a vaginal birth will be attempted. If Baby B is breech or transverse an internal or external version may be attempted to help facilitate the birth, or that baby may be allowed to be born breech.

Monoamniotic twins will also be born via cesarean, due to the added risk of cord entanglement.

No matter how your twins were conceived, or how they were born, babies are delightful. Parenting multiples has its special challenges, but it also yields special rewards.

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