Fertility Drugs And The Risk of Multiple Births


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Infertility treatments that cause multiple eggs to develop make it more likely that you will become pregnant with twins, triplets, or more. This is called multiple gestation. You might think it would be nice to have many babies at once, but this may not be good for the health of you or your babies. 

How likely is multiple gestation?

Very possible. Depending on the type of fertility treatment used, if more than one follicle is produced, the risk of multiple gestation can be as much as 1 out of 3 women who become pregnant. 

What could happen to the babies?

The babies could be born too early, which is called premature birth. Half of all twins and 90% of all triplets are born prematurely. Babies born prematurely may have many health problems.   Their lungs might not be strong enough, so they might have trouble breathing. The blood vessels in their brains might bleed easily. Many other birth defects are associated with multiple births as well.  The babies will probably be underweight and may get sick or even die. 

Before birth, the babies might not get all the nutrition that is carried by the blood from their mother. This is particularly true if they share a placenta, the tissue that carries nutrients from the mother to the baby. The babies may not grow as fast as normal. If the multiple babies share important blood vessels through a common placenta, they may develop heart problems or die. 

Twins, triplets, and other multiples are more likely to have problems with their brain development and nerves if they are born early. One of the more common problems is cerebral palsy, an abnormality of the brain. Other problems associated with multiple births may not become known for many years after delivery. 

What could happen to the mom?

If you are pregnant with more than one baby, you may experience problems during pregnancy. These potential problems could include high blood pressure, diabetes, anemia (low blood count), or too much or too little amniotic fluid (the fluid that surrounds the baby during pregnancy). Too much amniotic fluid can be a problem because it can cause premature labor, while too little fluid can cause a problem with the baby’s development. You may need to stay in bed or in the hospital for weeks before delivery. This is especially likely if you go into labor early. 

Also, you may have problems delivering your babies. There is a higher likelihood of undergoing a Cesarean section, which is when the babies are delivered through a surgical opening in your belly. 

What can I do to reduce the risk of multiple births?

During a fertility treatment cycle when fertility drugs are used with timed intercourse or insemination, your doctor will monitor your cycle very carefully. The use of fertility medications makes it more likely that one or more eggs will be fertilized. However, if it appears that too many eggs are developing, your doctor may cancel your cycle and tell you not to have insemination or intercourse to eliminate your risk of multiple births. 

In vitro fertilization (IVF) means that your egg and your partner’s sperm are joined (fertilized) in the laboratory, and the doctor places the fertilized eggs (embryos) into your womb. It is much less likely that you will become pregnant with triplets or more if only one or two embryos are placed in your womb. Before the placement of these embryos (embryo transfer), you and your doctor will decide how many embryos to place in your womb. ASRM has published guidelines on the number of embryos to transfer when undergoing an IVF cycle.  These guidelines can be found at www.asrm.org.

If three or more embryos implant inside your uterus, your doctor may suggest that you undergo a procedure called selective reduction. Selective reduction allows you and your doctor to reduce the number of fetuses to one or two. Usually the procedure is done early in the pregnancy to increase the chance of a healthy and successful pregnancy. Choosing to do this procedure is difficult. Couples who are thinking about this option should talk to a counselor.

Fact Sheets/Booklets

View more fact sheets and booklets written by the ASRM Patient Education Committee.
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Assisted Reproductive Technologies (booklet)

This booklet will help you understand in vitro fertilization (IVF) and other assisted reproductive technology (ART) that have become accepted medical treatments for infertility.
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Hormonal Contraception

Hormonal contraceptives contain a progestin (progesterone medicine) with or without an estrogen.
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What do I need to know about Zika virus and trying to have a baby?

Common symptoms include fever, rash, joint pain, conjunctivitis (red eyes), muscle pain, and headache.
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Third-Party Reproduction

The phrase “third-party reproduction” refers to involving someone other than the individual or couple that plans to raise the child (intended parent[s]) in the process of reproduction.

Resources For You

The American Society for Reproductive Medicine (ASRM) is committed to providing patients with the highest quality information about reproductive care.

Multiple Births or Multiple Gestation

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Multiple Pregnancy and Multiple Births: Understanding the Risks for Mothers and Babies

Research shows that women carrying twins and triplets are at greater risk for complications than women carrying one baby. Watch Video
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Multiple Pregnancy

Multiple Pregnancy is a pregnancy that includes more than one fetus and is much more common today than in the past. As attractive and efficient as a multiple pregnancy may sound, there can be significant risks associated with carrying, delivering, and raising multiple children. The goal is one healthy baby at a time. Watch Video
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Oral medicines for inducing ovulation

Some women may need medicines to help them ovulate (release eggs). View the fact sheet
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What do I need to worry about with a multiple pregnancy?

Women who take fertility medicines to get pregnant have a higher chance of having more than one fetus in a pregnancy. VIew the fact sheet
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Multiple Pregnancy and Birth: Twins, Triplets, and High-order Multiples (booklet)

Multiple births are much more common today than they were in the past. Read the booklet
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Side effects of injectable fertility drugs (gonadotropins)

Gonadotropins are fertility medications given by injection that contain follicle-stimulating hormone (FSH) alone or combined with luteinizing hormone (LH). View the fact sheet
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Challenges of Parenting Multiples

There are many psychological, social, and economic issues associated with multiple pregnancies. View the Fact Sheet
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Multiple Births or Multiple Gestation Infographics

ASRM has prepared infographics to illustrate the subject of Multiple Births or Multiple Gestation better. View the infographics

Ovulation Drugs

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Medications for Inducing Ovulation (booklet)

Medication can be used: 1) to cause ovulation in a woman who does not ovulate regularly, and 2) to cause multiple eggs to develop and be released at one time. View the booklet
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Oral medicines for inducing ovulation

Some women may need medicines to help them ovulate (release eggs). View the fact sheet
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Ovarian hyperstimulation syndrome (OHSS)

Ovarian hyperstimulation syndrome (OHSS) is an excessive responseto taking the medicines (especially injectable gonadotropins) used to make eggs grow. View the fact sheet
Patient Ed Icon

Side effects of injectable fertility drugs (gonadotropins)

Gonadotropins are fertility medications given by injection that contain follicle-stimulating hormone (FSH) alone or combined with luteinizing hormone (LH). View the fact sheet

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