Interests

How do multiple pregnancies happen?

There are two main ways that a multiple pregnancy can happen:-

• One fertilized egg (ovum) splits before it implants in the uterine lining
• Two or more separate eggs are fertilized by different sperm at the same time

These two different types of multiple pregnancy result in either identical or fraternal siblings. The difference between identical and fraternal babies goes back to how the multiple pregnancy happens.

Identical twins or triplets happen when a single egg is fertilized and then later splits. These newly divided embryos are identical. Children that are identical multiples will look like each other and be the same sex.

Fraternal multiples develop from separate eggs that are fertilized by a different sperm. Because these are different eggs and different sperm, the genetic material is varied. These children won’t look identical and can be different sexes from each other.

In a pregnancy with triplets or more, your babies could be all identical, all fraternal or a mixture of both. This can happen if your body releases multiple eggs and more than one is fertilized. In a case where you have both identical and fraternal multiples, more than one egg was fertilized and then at least one of those eggs also split after fertilization.

Are identical twins or triplets always the same sex?

Because identical twins or triplets share genetic material, they are always the same sex. The sex of a baby is determined by the particular sperm cell that fertilizes the egg at conception. There are two kinds of sperm cells — those carrying an X chromosome or Y chromosome. The mother’s egg carries an X chromosome. If a sperm cell carrying an X chromosome fertilizes the egg, it will make a XX combination (female). If the sperm cell is carrying a Y chromosome, you end up with an XY pairing (male).

Identical multiples start as one egg and then split, so whatever chromosome combination is present at fertilization is the sex of all multiples.

What increases the chance of a multiple pregnancy?

There are several factors that can increase the risk of a multiple birth. You might be at a higher risk of getting pregnant with more than one baby at a time if you:

• Are older (women in their 30s are at a higher risk of multiples because the body starts to release multiple eggs at one time when you get older)
• Are a twin yourself or have twins in your family
• Are using fertility drugs

You might also be at a higher risk of a multiple pregnancy if you are taller than average or have a higher body weight.

Another risk factor for a multiple pregnancy is genetic. There is an increased possibility of a multiple pregnancy if you are a multiple yourself, or if multiples run in your family. This heredity trait is generally passed down through the maternal (mother’s) side of the family.

The use of fertility drugs can be another reason you might have a multiple birth. Treatments for infertility can increase your risk of a multiple pregnancy because procedures, like in vitro fertilization (IVF), often involve transferring more than one fertilized egg into your uterus. Your provider usually transfers more than one egg at a time to increase the odds of a successful pregnancy.

How common are multiple births?

Multiple births have become more common in recent years because more people are using fertility drugs and procedures, such as IVF, to help conceive a baby.

What are the signs of a multiple pregnancy?

The only way to know if you’re pregnant with more than one baby during your pregnancy is through an ultrasound exam with your healthcare provider. During this test, your provider can look at images of the inside of your uterus and confirm how many babies are in there.

You might experience more intense symptoms during a multiple pregnancy than with a single pregnancy. These can include:

• Severe nausea and vomiting (morning sickness)
• Rapid weight gain in the first trimester of pregnancy
• Sore or very tender breasts
• High human chorionic gonadotrophin (hCG) levels — this hormone is made during pregnancy and is what a pregnancy test picks up.
• High amounts of the protein alpha-fetoprotein in your blood

Apart from an ultrasound, your provider might suspect multiples if there’s more than one heartbeat detected during a fetal Doppler scan.

What complications are linked to multiple births?

Anyone can experience complications during pregnancy — regardless of how many babies you’re carrying. However, most healthcare providers consider multiple pregnancies higher risk than single pregnancies. This doesn’t mean that every woman who carries more than one baby during a pregnancy is going to have problems. If you’re pregnant with multiples, your provider will want to watch you for possible complications that can happen when you carry more than one baby at once. Your provider will talk to you about each risk factor and frequently check with you to make sure you aren’t experiencing anything concerning.

Possible complications include:

• Premature labor and birth: The most common complication of multiple births is premature labor. If you’re pregnant for multiples, you are more likely to go into premature labor (before 37 weeks) than a woman carrying only one baby. The goal for many moms of multiples is to complete 37 weeks. This is considered term in a twin pregnancy and reaching this week of gestation increases the chance the babies will be born healthy and at a good weight. Babies that are born prematurely are at risk of another complication of multiple births — low birth weight.
• Preeclampsia or gestational hypertension (high blood pressure): High blood pressure is called hypertension. During pregnancy, your healthcare provider will watch your blood pressure carefully to make sure you don’t develop gestational hypertension (high blood pressure during pregnancy). This can lead to a dangerous condition called preeclampsia. Complications related to high blood pressure happen at twice the rate in women carrying multiples compared to women pregnant with only one baby. This complication also tends to happen earlier in pregnancy and be more severe in multiple pregnancies than single pregnancies.
• Gestational diabetes: You can develop diabetes during pregnancy. This happens because of the increased amount of hormones from the placenta. The size of the placenta can also be a factor in this condition. If you have two placentas, there’s an increased resistance to insulin.
• Placenta abruption: This condition happens when the placenta detaches (separates) from the wall of your uterus before delivery. This is an emergency situation. Placenta abruption is more common in women who are carrying multiples.
• Fetal growth restriction: This condition can also be called intrauterine growth restriction (IUGR) or small for gestational age (SGA). This condition happens when one or more of your babies is not growing at the proper rate. This condition might cause the babies to be born prematurely or at a low birth-weight. Nearly half of pregnancies with more than one baby have this problem.

Fraternal twins always have two placentas. The risks of pregnancies with fraternal twins are similar to those of pregnancies with only one baby. However, the number of possible risks are increased when compared to pregnancies with one baby.

Identical twins may have one placenta (70% of the cases) or two placentas (30% of the cases). The risks of identical twins with two placentas are similar to those listed above for fraternal twins. Identical twins with one placenta (called monochorionic) have risks that are unique to them. In 5 to 15% of the cases, they may develop a condition called twin-twin-transfusion-syndrome (TTTS). This is the consequence of vascular communications at the placenta level between the twins. Due to these communications, the twins may share their blood. When this happens — if nothing is done — there is a 90% risk that the twins will die in-utero. In-utero procedures are performed to decrease the fetal death risk for the twins.

Another complication that can happen in identical twins with one placenta is called twin-anemia-polycythemia sequence (TAPS). This is due to blood that goes from one twin to the co-twin because of vascular communications at the placental level. In this condition, one twin becomes anemic (low red-blood cells), whereas the co-twin becomes polycythemic (too many red-blood cells). Several treatments/interventions are performed when this happens.

A third condition that can occur in identical twins with one placenta is called” selective IUGR”. One twin grows well, whereas the co-twin does not experience much growth.

Another condition typical of identical twins is called twin-reversed-arterial-perfusion syndrome. In this condition, the heart of one twin pumps blood for the circulation of both twins. One twin does not have the heart and will not survive following birth. The outcome of the twin with the normal heart varies. Fortunately, this syndrome is rare (1 in 20,000 to 40,000) and it is amenable to in-utero procedures.

Identical twins with one placenta may also be in the same sac. They are called monochorionic (one placenta)-monoamniotic (one gestational sac). This pregnancy occurs in 1% of multiple gestations and it’s associated with an increased risk for one or both twins.

Your healthcare provider will diagnose the above conditions with an ultrasound.

Am I more likely to have a C-section delivery if I’m carrying multiples?

A cesarean section is a procedure used to deliver a baby through an incision (cut) in the abdomen. This type of delivery might be used for a variety of reasons, but it’s fairly common in multiple births. Your chance of having a C-section for a multiple birth is higher than if you were pregnant for only one baby. However, even in single births, a C-section can sometimes be the safest option for delivery. Often, the babies aren’t in the right position for birth — head down. A C-section can also happen if you have a complication during pregnancy that means a vaginal birth isn’t the safest option for you or your babies. Your healthcare provider will monitor you leading up to your due date and talk to you about the best option for delivery.

What can I do to stay healthy during a multiple pregnancy?

Eating nutritious foods, getting enough rest, and visiting the doctor regularly are important steps for any pregnant woman to take toward a healthy pregnancy. These steps are especially important during multiple pregnancies.

If you’re expecting multiples, you have additional dietary needs to meet. Getting enough protein and enough hydration (fluids) is important. You’ll also need to make sure you get enough extra calories for the developing fetuses. One rule of thumb is to eat an extra 300 calories a day per baby. That means that if you’re pregnant with twins, you will need to add 600 calories to your daily diet. Talk to your healthcare provider about your diet and the specific amounts you’ll need for a healthy pregnancy.

Moms of multiples might also experience the typical discomforts of pregnancy more intensely. It’s important to take good care of yourself and get plenty of rest to help ease the stresses of pregnancy.

In some cases, you might want to find a healthcare provider who has experience with multiple births. Specialized healthcare can help ensure that you and your babies are receiving the best care available. The need for frequent, intensive prenatal care is very important in a multiple pregnancy. Talk to your family doctor or OBGYN about their recommendations for specialists.

Can I be active and exercise during a multiple pregnancy?

Exercise and activity is an important part of any pregnancy. In most cases, you can absolutely exercise during a multiple pregnancy. Low-impact exercises are a great way to stay in shape and maintain your health throughout pregnancy. Some low-impact exercises to try during a multiple pregnancy can include:

• Swimming
• Walking
• Prenatal yoga

Even though activity is wonderful during pregnancy, you should talk to your healthcare provider about the best activities for you. Some more strenuous activities might not be a good idea during a multiple pregnancy, including:

• Jogging
• Aerobics that involve jumping

It’s also important to remember that your exercise routine might need to change over time if you experience any complications.

Age

Pregnancy risks tend to be higher for pregnant people who are younger than 20 or who are older than 35.

Lifestyle choices

A variety of lifestyle choices can put a pregnancy at risk. Examples include:

• Drinking alcohol
• Smoking cigarettes, vaping or using other tobacco products
• Using illegal drugs

Health problems

Some medical conditions in a pregnant person can raise pregnancy risks, including:

• High blood pressure
• Obesity
• Diabetes
• Epilepsy
• Thyroid disease
• Heart or blood disorders
• Poorly controlled asthma
• Infections

Pregnancy complications

Some health problems that develop during pregnancy can cause problems. Examples include:

• Unusual location of the placenta
• Very low fetal growth. Usually, overall fetal growth or a fetal abdomen size that's less than the 10th percentile for gestational age is cause for concern. This condition is called fetal growth restriction
• Rh sensitization. This happens when a pregnant person's blood group is Rh negative and the fetus's blood group is Rh positive

Pregnancy with multiples

Risks to both a pregnant person and the fetuses are higher when a pregnancy includes more than one fetus.

The likelihood of having more than one fetus is higher in people who have gone through infertility treatments to get pregnant. Those treatments also are called assisted reproductive technologies (ART). One common type of ART is in vitro fertilization. The use of ART may raise the risk of some medical concerns during pregnancy, such as diabetes or high blood pressure.

Pregnancy history

Medical problems that happened during a previous pregnancy may raise the risk of having the same problems again. Examples include:

• Conditions during pregnancy related to high blood pressure, such as preeclampsia
• Giving birth early. This is called preterm delivery
• Having a baby born with a genetic condition
• Having a miscarriage or stillbirth

It's important to tell your healthcare professional about any medical problems that you had during other pregnancies.

What steps can I take for a healthy pregnancy?

You may know ahead of time that you'll have a high-risk pregnancy. Or you might want to do what you can to prevent a high-risk pregnancy. Either way, take the following steps.

Schedule an appointment before you get pregnant If you're thinking about becoming pregnant, make an appointment to see your healthcare professional. During that appointment, you'll likely talk about:

• Taking a daily prenatal vitamin with folic acid
• How to best manage any medical conditions you may have
• All medicines you take, including those without a prescription
• Vaccinations you may need
• Your family and personal medical history
• Your risk of having a baby with a genetic condition
• Your partner's health
• How you can prepare for a healthy pregnancy. For example, quitting smoking and being at a healthy weight before you become pregnant can lower some risks

Get the care you need during pregnancy

Appointments with your healthcare team on a regular basis during pregnancy allows the team to follow your health and your baby's health. You might be referred to a specialist. Depending on your situation, you may see a specialist in maternal-fetal medicine, genetics, pediatrics or other areas.

Avoid risky substances

If you use any form of tobacco or e-cigarettes, quit. Don't drink alcohol or take illegal drugs during pregnancy. Tell your healthcare professional about any medicines or supplements you take.

Do I need special tests?

Depending on the circumstances, your healthcare professional might suggest certain tests. The following are examples of tests that may be part of care during a high-risk pregnancy. The decision to get these tests is up to you. Talk about the risks and benefits with your healthcare professional.

Specialized ultrasounds

An ultrasound is an imaging test that uses high-frequency sound waves to make images of a fetus on a screen. Ultrasound is safe for both pregnant people and fetuses.

The following kinds of ultrasound may be helpful during a high-risk pregnancy:

• Three-dimensional (3D) or 4-dimensional (4D) ultrasounds can be used to pinpoint a suspected problem, such as fetal development that's not typical
• Ultrasound to measure the length of the cervix can help determine if you're at risk for going into labor early
• A biophysical profile is an ultrasound that can be used to check a fetus's health. Depending on the ultrasound results, your team also may check a fetus's heart rate. That procedure is called a non-stress test

Cell-free DNA screening

This test sometimes is called cfDNA. It uses a blood sample from you to provide the healthcare team with your DNA and the fetus's DNA. A small amount of DNA from the fetus goes into a pregnant person's blood stream during pregnancy. Through the blood sample, the fetus's DNA is checked to see if there's a higher chance of certain chromosome problems. If so, those problems could signal a genetic condition.

Other genetic tests

Your healthcare professional might suggest amniocentesis or chorionic villus sampling (CVS). These tests can help find genetic conditions. They also can be used to confirm results from cell-free DNA screening.

• Amniocentesis. During amniocentesis, a sample of the fluid that surrounds and protects a fetus during pregnancy is taken from the uterus. The medical term for that fluid is amniotic fluid. Usually done after week 15 of pregnancy, the test can identify some genetic conditions. It also can find serious problems of the brain or spinal cord. Those conditions are called neural tube defects
• CVS. During CVS, a sample of cells is taken from the placenta. It's usually done between weeks 10 and 13 of pregnancy

Lab tests

Your healthcare team can run lab tests on a blood or urine sample from you to check for infections, anemia and diabetes. The tests also can be used to identify a higher risk of genetic conditions.

What else do I need to know about high-risk pregnancy?

Talk to your healthcare professional about how to manage any medical conditions you have during pregnancy. Ask how those conditions could affect labor and delivery.

Contact a member of your healthcare team right away if you have:

• Vaginal bleeding
• Watery vaginal discharge
• Pain or cramping in your abdomen or pelvis area
• Less fetal activity than usual
• Severe headaches
• Pain or burning when you urinate
• Changes in vision, including blurred vision
• Sudden or severe swelling in the face, hands or fingers.
• Fever or chills
• Vomiting or frequent nausea
• Chest pain or shortness of breath
• Dizziness
• Weakness
• Extreme tiredness
• Nervousness or worry that makes it hard for you to do your daily activities
• Overwhelming feelings of sadness or sadness that lasts
• Thoughts of harming yourself or your baby

Having a high-risk pregnancy may be stressful and cause you to worry about your baby's health. Try to do what you can to ensure a healthy pregnancy. Throughout your pregnancy, talk to a member of your healthcare team if you have questions or need support. After pregnancy, discuss with your healthcare professional how medical conditions during pregnancy might affect your long-term health.

Some genetic conditions may be inherited (passed down) from one or both parents. Genetic conditions can also be caused by changes in the number of your chromosomes (the structures that carry your genes).

Some of the genetic or chromosomal conditions people may talk to a genetic counsellor about are:

• Cri du chat syndrome
• Cystic fibrosis
• Down syndrome (trisomy 21)
• Edwards syndrome (trisomy 18)
• Fragile X syndrome
• Haemophilia
• Muscular dystrophy

What is a genetic counsellor?

Genetic counsellors are health professionals who have qualifications in both genetics and counselling. They have special skills in health communication.

A genetic counsellor can:

• Talk you through genetic testing
• Help you understand your test results and what they mean for you and your family
• Give emotional and practical support if you have (or are at risk of) a genetic condition
• Help you and your family adjust to living with a genetic condition and plan for the future
• Genetic counsellors often work closely with clinical geneticists (doctors who specialise in treating genetic disorders).

What can I expect in a genetic counselling session?

Genetic counselling sessions usually involve:

• Talking about your family and any conditions that are common in your family.
• Learning about specific conditions and how they are inherited.
• Finding out what tests are available.
• Talking about how to manage and prevent conditions.
• Learning what support and resources exist.
• Organising genetic tests.
• Understanding test results.
• Giving advice on support services.

When might I see a genetic counsellor?

There are many reasons to see a genetic counsellor.

Planning for pregnancy

If you are planning a pregnancy, you may want to see a genetic counsellor if:

• You have a genetic condition
• There is a chance you have a genetic condition because it runs in your family
• You want to understand the likelihood of your baby having a genetic condition

During pregnancy:

There are screening tests that are offered during pregnancy. These tests are called prenatal screening tests, or genetic screening in pregnancy tests. They can tell you whether your baby may be at increased risk of certain genetic or chromosomal conditions.

If prenatal screening tests show your baby has an increased risk, your doctor may recommend you:

• See a genetic counsellor to discuss your options
• Have further tests

Diagnostic tests that can confirm if your baby has certain genetic conditions include:

• Amniocentesis
• Chorionic villus sampling (CVS)

Genetic counselling can help you make an informed decision about whether to have additional testing.

A genetic counsellor can also support you and give you information if a genetic condition is diagnosed during pregnancy.

Caring for your child

Your doctor may recommend you see a genetic counsellor if your child has signs of a genetic disorder.

This can provide you with information on testing and diagnosis, as well as support. You may also want information on the risks to potential future children.

What is genetic testing and when might it be done?

Genetic testing can be done to diagnose some genetic conditions. There are several different types of genetic tests.

Testing can be done:

• If you have symptoms of a genetic condition
• If you have a family history of a genetic condition
• During pregnancy, to check your baby for certain conditions (if they are at increased risk)

Genetic carrier screening tests are tests to find out your chance of passing a genetic condition on to your children.

How can I find a genetic counsellor?

Genetic counsellors are available in many hospitals and health clinics in Australia. The best way to find a genetic counsellor is to speak to your doctor. They can refer you for genetic counselling.