Having twins, triplets or other multiples increases the risk of developing complications of pregnancy. These complications include:
Premature birth
The most common complication of twin and multiple pregnancies is low birthweight (below 5.5lb) and premature (early) birth. Babies who are born before 37 weeks of pregnancy are usually described as premature. 60% of all twins and 80% of all triplets are born prematurely.
Prematurity increases the risk of serious health problems for newborn babies whose organs may not have fully developed at the time of birth. They need help with breathing, feeding, controlling their body temperature or fighting infection. They are also at risk of injury from other serious conditions which need early diagnosis and treatment, such as blindness from retinopathy of prematurity (ROP) in babies whose retina has not fully developed before birth. For this reason, premature babies usually need specialist care in a neonatal intensive care unit (NICU or SCBU) after birth.
Anaemia
Anaemia in pregnancy may be caused by lack of iron. Treatments for anaemia include making changes to the mother’s diet, and taking supplements, such as iron tablets and folic acid. Untreated anaemia increases the risk of life-threatening injury to the mother and unborn baby from harmful conditions, such as IUGR (intra-uterine growth restriction), infection, heart failure and bleeding.
Intrauterine growth restriction (IUGR)
Babies with IUGR fail to grow at the expected rate for their gestational age (number of weeks of pregnancy). It is not unusual for twins to be slightly smaller than single babies, but where one or both twins are not growing properly their lives may be at risk if the growth restriction is caused by problems with the umbilical cord or the placenta. The twins’ growth should be checked regularly by ultrasound scans, and charted during pregnancy, so that any signs of IUGR are detected early and, if needed, the twins can be delivered prematurely.
High blood pressure (hypertension), pre-eclampsia and HELLP syndrome
Women who are expecting twins have more than double the risk of developing high blood pressure (hypertension) when compared to women with ‘singleton’ pregnancies. Hypertension in twin pregnancy may also develop earlier and be more severe than in a pregnancy with one baby. Hypertension in pregnancy increases the risk of detachment of the placenta (placental abruption).
High blood pressure can also be a sign of other serious conditions.
High blood pressure and protein in the mother’s urine (proteinuria) during pregnancy may indicate that the woman is developing pre-eclampsia. Other symptoms of this dangerous condition include severe headaches, swelling (oedema) of the ankles, face or hands, visual disturbance and abdominal pain. If a pregnant woman shows signs of pre-eclampsia she must be monitored carefully and treated to avoid serious injury to herself and her baby/babies. Treatment for pre-eclampsia usually involves admission to hospital, bedrest, medication and careful monitoring, to bring the mother’s blood pressure down to safe levels. If the mother’s blood pressure remains above safe levels, it may be necessary to deliver the baby/babies prematurely to avoid serious injury.
HELLP syndrome is a very dangerous condition which develops in the later stages of pregnancy and needs urgent treatment as it is potentially life-threatening for both mother and baby/babies. It is similar to pre-eclampsia but is often misdiagnosed, causing delays in vital treatment. HELLP is an acronym taken from the key features of the condition, which include Haemolysis (breakdown of red blood cells), ELevated liver enzymes and Low Platelet count (affecting blood clotting). Treatment for HELLP usually involves delivery of the baby/babies, and the mother receiving a blood transfusion. If HELLP is left untreated, the mother may become critically ill or die from liver rupture or stroke. The unborn babies may be stillborn or suffer brain injury from placental failure or abruption.
Gestational diabetes
When a woman develops diabetes in pregnancy it is known as gestational diabetes. This type of diabetes can often be managed by diet and exercise. If the condition is severe, then the mother may need tablets or insulin injections to keep her blood sugar within safe levels. Gestational diabetes must be diagnosed, monitored and kept under control. Uncontrolled gestational diabetes increases the risk of developing many of the complications of pregnancy, such as high blood pressure, pre-eclampsia, shoulder dystocia, stillbirth, prematurity. It can also cause problems for the newborn baby, such as breathing (respiratory) difficulties, neonatal hypoglycaemia and jaundice.
Twin-to-twin transfusion syndrome (TTTS)
Twin-to-twin-transfusion syndrome or TTTS is a rare but serious complication of twin pregnancy, triplets and other multiple births. TTTS affects 10-15% of identical twins who share a placenta (monochorionic). MCDA (monochorionic diamniotic) twins have the highest risk of developing TTTS, but MCMA (monochorionic monoamniotic) twins can also be affected.
Twin-to-twin-transfusion syndrome occurs when abnormalities in the blood vessels of the placenta allow more blood to flow to one twin than the other. The twin who receives less blood (the ‘donor twin’) is left undernourished and anaemic. The twin who receives too much blood (the ‘recipient twin’) may suffer heart failure from their cardiovascular system becoming overloaded, and complications from too much amniotic fluid.
If a woman who is pregnant with MCDA or MCMA twins experiences any of the following ‘red flag’ warning symptoms for TTTS, she should seek medical help straight away:
• sudden swelling or distension of the abdomen;
• abdominal pain;
• sudden breathlessness;
• inability to lie on her back;
• reduced fetal movements.
When TTTS is suspected in a twin pregnancy, frequent ultrasound scanning must take place to monitor the babies’ growth and health. The mother may need to be referred urgently to a fetal medicine centre for specialist treatment. Any delays in diagnosis of TTTS or referral to a specialist fetal medicine centre for treatment can result in death or brain injury to the unborn babies.
Breech presentation and delivery of twins
When a baby is positioned in their mother’s uterus (womb) with their bottom or feet down (instead of head down) in the last weeks of pregnancy this is known as a breech presentation. This can happen in any pregnancy, but it is common in twin pregnancies for one twin to be in the breech position.
In twin or multiple pregnancies, it is important that the method and timing of the babies’ delivery is carefully planned in advance with the mother and an experienced obstetrician. Twin births should be managed in hospital under the care of a multi-disciplinary maternity team including midwives, an obstetrician and paediatricians. Throughout labour and delivery the unborn twins must be monitored carefully with electronic fetal heart monitoring, such as CTG or fetal scalp electrode.
Twin births are often recommended to take place by caesarean section, especially if the first twin is in the breech position or the second twin is in transverse position. However, once labour has started, it may be safer for the babies to be delivered vaginally. Vaginal breech deliveries of twins need careful management by obstetricians who are skilled in handling the complications of multiple births and vaginal breech delivery. Severe brain injury to babies (and birth injury compensation claims) commonly arise from maternity emergencies in which inexperienced or unskilled junior obstetricians are left to manage unplanned vaginal breech deliveries.
