More about the management of monoamniotic pregnancy

Understanding Monoamniotic Monochorionic Twins

Jocasta’s Story (Monoamniotic Monochorionic Twins)

 

 

Strategies to reduce the risk of premature birth

Given the high rates of prematurity for multiple births, is there anything that can be done to prevent it? Yes and no.

There are a range of medical conditions/complications, over which we have little or no control, that can result in an iatrogenic (planned) premature birth, including problems with your cervix or uterus, previous termination of pregnancy or preterm birth, intrauterine growth restriction, diabetes, pre-eclampsia and poor overall health.

There are also risk factors that we do have some, or complete, control over, that can contribute to prematurity, such as poor nutrition, smoking, stress, alcohol and drugs. Since a multiple gestation pregnancy is, itself, a known risk factor for premature birth, if you are pregnant with twins, you want to especially avoid these known risks.

Here are some proven strategies for prolonging pregnancy.

Stop smoking!

If you smoke, you NEED to stop—or, at the very least, reduce how much you are smoking. If you use alcohol or recreational drugs, a multiple pregnancy would be a good time to seek help to stop using them.

Antenatal care

Register for antenatal care early and let your LMC know about any previous gynaecological surgery, or previous health issues that may affect your care. At each visit, talk about how you are feeling and ask for information that will help you to stay healthy. If you have registered early, ask for ultrasound (before 16 weeks) to determine chorionicity, so that any risks can be fully assessed and referral organised.

Good nutrition and appropriate weight gain

Nutrition is very important if you are carrying twins: you need extra energy (calories), protein, iron, folate, calcium, vitamin D and essential fatty acids (e.g. fish oil capsules). Drink plenty of fluids (such as water anddiluted fruit juice) as thesewill help reduce the risk of urinary tract infections, which are thought to contribute to preterm birth.

Manage stress

Minimise stress levels by reducing extreme physical exertion, and ensuring that you get lots of rest. If possible, take early   maternity leave, and avoid major stressors, such as moving house or long-distance travel. If you are finding it tough, emotionally, talk to someone. Aim to keep 50% of your energy in reserve.

Monitor for preterm labour

Know the early warning signals of pre-term labour—and get medical help, fast! For many women, this will mean following your instincts that something is wrong. If premature labour is detected early enough, it is often possible to delay it; if not, you can be given steroids to help the babies lungs develop.

Be assertive

You will need to become an expert on your multiple pregnancy, and make sure that you get the care that you need. Dr Kennneth Moise, part of the ground-breaking Program for Multiples at the Texas Children's Fetal Center, suggests:

… if you're a mom expecting twins, my best advice is to be your own advocate. Start by asking the right questions. Find out if you are expecting fraternal or identical twins. Confirm that each baby has its own placenta and amniotic sac at your first ultrasound. Make sure the amniotic fluid levels stay balanced. Seek nutritional counselling from a registered dietician who understands the new guidelines for multiples. …[G]et frequent blood pressure checks, and request to be tested for anaemia and gestational diabetes at least twice during your pregnancy. Be assertive about scheduling additional ultrasounds - these should take place around 5 months to look for birth defects then every 4 weeks thereafter to watch your babies' growth.

 

Complications specific to multiple pregnancy

Some pregnancy complications only occur in twin and multiple pregnancies. These include selective intrauterine growth restriction (IUGR), Twin-to-Twin Transfusion Syndrome (TTTS) and cord entanglement in twins who share an amniotic sac.

Twin-to-Twin Transfusion Syndrome (TTTS)

Twin-to-Twin Transfusion Syndrome (TTTS) is a rare complication of twins and higher gestation pregnancies. The lives of both twins are endangered by this condition, and complications for surviving babies can include cerebral palsy. Treatment of TTTS with the laser fetoscope, available at Auckland Hospital, improves the survival rate of both twins to 50-60%, with a 75% chance that at least one twin will survive.

Early diagnosis of chorionicity is vital to detect TTTS. Dr Emma Parry, the Multiples NZ medical advisor, emphasises the need for early diagnosis of twin type (chorionicity) and regular scanning to identify the potential for problems early in the pregnancy:

About one-quarter of all twin pregnancies share a placenta. If you have a scan that shows you are having twins or higher-order multiples, it is important to find out if they are sharing a placenta before 16 weeks gestation, because after this scans are not accurate enough to diagnose whether the placenta is shared.

Dr Parry has devised a Guideline for the Management of Monochorionic Twins, where she discusses TTTS, and indicates that women who have been diagnosed with a monochorionic twin or multiple pregnancy need to have regular scans beginning at 16 weeks gestation, not the usual 20 weeks for twins who do not share a placenta. Dr Parry states that women also need to know the warning signs for TTTS:

Between 16 to 28 weeks, watch for a sudden increase in the size of your abdomen and shiny red skin, with a feeling of it being stretched or tight. If this happens, your doctor or midwife needs to arrange an urgent scan to assess what is happening.

To find out more about TTTS, click here.

Selective intra-uterine growth restriction (sIUGR)

Intrauterine growth restriction (IUGR) occurs in 3-10% of singleton pregnancies, 9% of twin pregnancies and 9.9% of monochorionic twin pregnancies. A fetus suffering from IUGR will be small for its gestational age and not growing at the normal, expected rate. IUGR, thought to be a result of problems with the placenta, can also be caused by health problems in the mother. It is diagnosed by ultrasound scanning of the babies’ growth. A difference in the rate of growth between the babies (growth discordance) in the first trimester may also indicate anatomical and chromosomal abnormalities.

Up to 32 weeks gestation, the growth rate for twins should be the same as for singletons, but after 32 weeks growth slows due to the restricted space in the womb/uterus and placental insufficiency—it is overworked growing twins! In triplets, this process starts earlier. The degree of difference in growth (growth discordance) between twin or multiple babies can indicate the degree of the IUGR:

•  Mild is less than 15% difference
•  Moderate is between 15-30% difference
•  Severe is more than 30% difference.

When evaluating the babies’ growth in a multiple pregnancy, it is important to know whether the twins are identical (chorionicity), as they are at a greater risk of IUGR which may be due to placental insufficiency, unequal placental sharing (ITP), placental cord abnormalities and TTTS. IUGR may affect one twin in 12-25% of pregnancies, especially with TTTS, where the difference in growth in the donor twin can be can be up to 85%. The complications of growth restriction that affects only one twin (selective IUGR, or sIUGR), include intrauterine death, which may cause the death or disability of the co-twin, or premature labour.

Abnormal growth discordance can occur in up to 30% of twin pregnancies, but most twins do well despite it. In the second trimester, treatment options include selective termination if one twin is abnormal, so that there is less risk of adverse impact on the co-twin. Should one twin die in-utero, the specialist team aims to get the pregnancy to 34 weeks before delivering the co-twin.

The management of a multiple gestation with severe growth discordance in the third trimester is fairly complex, and involves:

• Serial growth scans (ultrasounds every 1-2 weeks)
• Doppler blood flow studies (ultrasound procedure to measure the blood flow through the placental blood vessels)
•  Cardiotocographs (CTG fetal monitoring)
•  Possible admission for surveillance
•  Giving steroids between 24 and 34 weeks for fetal lung development.

If TTTS or placental cord abnormalities are involved, there are two main treatment options:

• Umbilical cord occlusion (via laser, bipolar coagulation or fetoscopy) for selective reduction (feticide) in order to save the co-twin from death or harm
• Selective Laser Photocoagulation of Communicating Vessels (SLPCV), a new treatment for severe TTTS, which may allow both twins to survive, and benefit the smaller twin. Studies into this area of fetal medicine continue.

To find out more about Intrauterine growth restriction, click here.

Cord entanglement in identical twins who share the same sac (monoamniotic twins)

The umbilical cords run from each baby to the placenta, on the wall of the uterus. They feed nutrients, oxygen and blood flow between the babies and the mother. By the time a fetus is full-term, its umbilical cord is around 50 cm long, allowing freedom for the fetus to move inside the womb. Any baby can get tangled in their own cord and there is a risk of compressing the cord (thus, cutting off the supply of nutrients, oxygen and blood) once the membranes have ruptured (during labour) and there is no longer as much fluid to cushion the cord. This risk occurs for each baby during a multiple birth.

So long as each baby in a multiple pregnancy has its own amniotic sac, they are at no risk of becoming tangled in their sibling’s cord. In a monoamniotic pregnancy, however, because the babies share a sac, the risk of cord entanglement is greater, as each baby is not only at risk of getting tangled in their own cord, but of also getting tangled in their sibling’s cord. Cord entanglements (also called ‘Cord Accidents’) are the number one risk in this type of pregnancy. 

To put this danger in perspective, virtually all cases of monoamniotic twins will have tangled cords. In order for entanglement to become dangerous, there must also be cord compression. It is very possible to have entanglement apparent as early as 10 weeks (and probably even earlier), and still have both babies born safely at 34 weeks with no complications. Nevertheless, as cord entanglement is the first sign of possible problems, expect the obstetricians to be on high-alert for it.

There are many pictures of cord entanglement on the Monoamniotic Monochorionic Support website (www.monoamniotic.org) that show the level of entanglement that babies can survive through. It may be comforting for some expectant parents to view these, but keep in mind that the pictures are graphic and disturbing.

The only treatment doctors can offer is expediting the birth. If serious problems are discovered before 24-26 weeks (the point of viability outside the womb), there is, sadly, nothing that can be done. After that point, if life-threatening problems are discovered, the babies can be born—although the earlier the birth occurs, the higher chance that the babies may suffer from complications due to extreme prematurity.

While some cord accidents are sudden, it appears that the majority of fatal cord accidents are gradual. Ultrasound, Doppler-imaging (a way of seeing actual blood flow through the cords), and fetal monitoring (CTGs) enable early detection of possible problems. This means that if you are watching often enough, signs of cord compression may be detected early enough to perform an emergency birth, before it is too late.

So, the key to managing a monoamniotic pregnancy is frequent assessment and monitoring. “How much, and how often”, is a question that you will have to address with your obstetrician. Generally speaking, more is better.

For more information about the management of monoamniotic pregnancy, click here.

You may also be interested to read Jocasta’s story—Monoamniotic Twins.

Pregnancy complications

Twin pregnancies have increased risks for both the mother and the babies. There is an increased risk of anaemia, vaginal bleeding, gestational diabetes mellitus (GDM) and pre-eclampsia—which occur in singleton pregnancies, but are more common in twin pregnancies. The most common complication in multiple pregnancy is the risk of premature labour and pre-term birth—this is covered in the following section.

Anaemia

Iron-deficiency anaemia affects 10-15% of pregnant women, and women with multiple pregnancy are at greater risk, as each subsequent baby puts extra strain on the mother’s iron intake. The mother’s body will prioritise the babies’ iron needs ahead of her own—this is good news, as it means that although the mother might be anaemic, her babies should still be getting sufficient iron. Although anaemia can cause serious problems, there is little risk to the babies unless the mother is severely anaemic.

It is routine to test for iron-deficiency anaemia during pregnancy. Pregnant women often appear to have low haemoglobin levels, as there is extra fluid in the blood during pregnancy, which dilutes the red blood cells. Only if your levels are seriously low, will it be considered cause for concern. Be sure to inform your LMC if you have an infection, though, as an infection will mean you test higher for haemoglobin levels, which may result in an under-diagnosis of iron deficiency. Also inform your LMC if you are a vegetarian or vegan.

When a woman is suspected of being iron deficient during pregnancy, a full iron blood screen should be conducted, and treatment initiated and followed-up. Following birth, a woman who has been iron deficient during pregnancy should have a further follow-up to check if she is still iron deficient. Iron deficiency during breastfeeding should be treated, because low iron status leads to an increased risk of illness, tiredness and breast infections. These can negatively impact on the mother’s ability to care for her infants and may also affect her breastfeeding.

Vaginal bleeding

Up to 10% of all women have bleeding during their pregnancy. This is more common with twins. Bleeding during the first trimester is common, usually as a result of implantation bleeding. It could, however, also be the result of a miscarriage or ectopic pregnancy. Bleeding in the second and/or third trimesters could indicate: a problem with the cervix; placental abruption; placenta praevia; preterm labour; or, miscarriage. If you have any bleeding during pregnancy, it is best to contact your LMC or specialist, especially if the bleeding is also accompanied by cramps or abdominal pains. It can be useful to wear a pad, so that you can determine how much you are bleeding. Never use a tampon during pregnancy. It may also be useful to discuss with your LMC or specialist, whether to avoid sexual intercourse during your pregnancy.

Gestational diabetes mellitus (GDM)

Gestational diabetes affects 2-3% of all pregnant women. In most cases, it is a temporary form of diabetes, brought on by the body’s inability to produce enough insulin during pregnancy. Screening for gestational diabetes is generally offered when a woman is   between 24 and 28 weeks gestation. This is normally done through a blood test with the results indicating whether gestational diabetes is a potential problem. If you are concerned or have a family history of GDM, discuss this with your specialist.

Pre-eclampsia

Pre-eclampsia is also known as Toxaemia and Pregnancy-Induced Hypertension (PIH), and affects around 3-8% of all pregnant women—about 1 in 3 mothers pregnant with twins will develop it.

The signs of pre-eclampsia are high blood-pressure and protein in the urine. It only occurs during pregnancy, usually after 20 weeks gestation, but rarely before 32 weeks. Often women diagnosed with pre-eclampsia feel fine, but some of the signs and symptoms can include swelling (oedema) of the face or hands, sudden weight gain, headaches and changes in vision. If left untreated, pre-eclampsia can be life-threatening.

The only remedy for pre-eclampsia is delivery of the babies. The specialist will balance the risk to the babies of being born prematurely, against the risk to the mother from pre-eclampsia. If pre-eclampsia develops too early in the pregnancy for the babies to be delivered safely, the pre-eclampsia will likely be managed by having the mother on full-time bed-rest, possibly in hospital. Sometimes medication to lower the mother’s blood pressure will be administered. Usually, pre-eclampsia goes away after the babies are born, as the mother’s blood pressure gradually reduces.

Premature labour and preterm birth

Preterm birth generally occurs in 7-10% of all births—for twin births this rises to 50%, of which 20% are less than 34 weeks, and 6-7% are less than 32 weeks gestation. Mothers of multiples are more likely to experience per-term labour because between 29 and 32 weeks gestation, the uterus is the same size as a full term singleton pregnancy. Babies born before 36 weeks are considered pre-term. Babies born after 26 weeks have a good chance of survival.

Signs and symptoms of premature labour

When pregnant with multiples, it is vital to know some of the signs and symptoms that might indicate that labour is starting because the risk of preterm labour and birth are higher. It is not always easy to know if you are experiencing premature labour, as often the signs and symptoms are very subtle—you may just feel that something is not right. Here are a few signals to watch out for:

• Dull low back ache—this pain might be continuous or intermittent, it will not be related to posture, and might branch out to your front or sides
• Rhythmic or persistent pelvic pressure (feels like the babies are pushing down)—you may experience this pain in your back or thighs
• Abdominal cramping, with or without diarrhoea (like period cramps)
• Diarrhoea, gas pains, or intestinal discomfort
• An increase or change in vaginal discharge (blood, water or mucus)
• Tightening across your abdomen—this may be painless and are often called Braxton-Hicks contractions; they generally ease with rest but if they become frequent and prolonged you should seek advice
• Feeling ‘bad’
• A ‘heavy’ feeling.

It is always best to get discuss these signs and symptoms with your maternity care provider (LMC or specialist) and ask for a physical assessment. It is better to be checked earlier than later, just to be on the safe side—don’t wait for the symptoms to go away!

If you have any of the following, contact your LMC/specialist and/or the hospital maternity unit and prepare to go to the maternity unit/birthing suite immediately:

• Water leaking or gushing from the vagina
• A show (a white or pink mucus discharge)
• Bleeding from the vagina
• Regular, painful contractions—during a contraction the uterus tightens, becomes hard and then relaxes again
• If you just feel something is not right—trust your intuition.

 

For information on strategies to reduce the risk of premature birth, click here.