What are the Different Types of Multiple Pregnancy?听
听Twins are the most听common form听of multiple pregnancy. There are听different types听of twin pregnancy as explained below.听It is important to know what type of twins you are carrying because the risks are different depending on whether the twins have separate placentas.听
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Dichorionic Diamniotic (DCDA) Twins听
These twins are often non-identical resulting from two separate fertilised eggs. They can also be identical when one fertilised egg splits听very early听in development. Each twin is in its own sac with a separate placenta. The placentas can sometimes be next to听each other听but the membranes are separate so there is no sharing of the babies鈥� blood supplies.听
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Monochorionic Diamniotic (MCDA) Twins听
These twins result from one fertilised egg which splits in two early in development meaning these twins will be identical. The twins are in two separate听sacs听but the placentas are joined to each other and there may be sharing the babies鈥� blood supplies. When this sharing is unequal a problem called twin-twin transfusion syndrome can develop. Twin-twin transfusion syndrome affects 1 in 10 cases of monochorionic twins and is discussed later in this leaflet.听
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Monochorionic Monoamniotic (MCMA) Twins听
These twins result from one fertilised egg which has split later in development. These twins are identical and share a sac. This type of twin pregnancy is unusual and carries higher risks. If you have MCMA twins you will be referred to the听Fetal听Medicine Unit in听Leeds听for ongoing care.听
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Triplets and More听
Triplets can be any of the above (or a combination of them). Triplets carry higher risks of complications. Your obstetrician will discuss with you whether referral to Leeds听Fetal听Medicine is听advised听depending on your听particular case.听
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How will I know if I am carrying a multiple pregnancy and what type it is?听
Many women will not know they are carrying a multiple pregnancy until they attend for their dating scan at 11- 14 weeks. Some women will have more severe symptoms in early pregnancy such as morning sickness, tiredness etc.听
听During the dating scan the sonographer will count how many babies you are carrying and will also look to see whether the babies are in separate sacs and if the placentas are separate.听
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What problems are more likely in twin pregnancies?听
The common symptoms of pregnancy such as听morning sickness,听heart burn,听swelling of the ankles,听tiredness听etc may be increased.听
There is an increased risk of听anaemia听(low iron) as you will be supplying iron to help two babies develop.听You may be advised to听take iron if your blood tests show your iron levels are becoming low.听
There is an increased risk of听pre-eclampsia (high blood pressure with protein in the urine). If you have other risk factors (eg听you are aged 40 or more or if these are your first babies)听you may be advised to听take a small dose of aspirin from 12 weeks until birth.听
There is an increased risk听of听听gestational听diabetes.听You may be advised to听have听a听test for this at 26 weeks if you have other risk factors. This will be discussed with you if it is听required.听
Twins are at increased risk of having听problems with growth听in the womb. You will be听monitored听throughout the pregnancy by ultrasound to check how the babies are growing.听
Twins are more likely to听deliver before 37 weeks. Babies born prematurely may need help with breathing and feeding. Babies born before 32 weeks are more likely to need Neonatal Intensive Care and if听very early听delivery looks likely we may decide to transfer you to a hospital with a Neonatal Intensive Care Unit for delivery.听听If you think your membranes have ruptured or you are experiencing painful听contractions听you should contact the Delivery Suite as soon as possible for advice.听
If you are carrying听monochorionic听twins there is a risk of听twin-twin transfusion syndrome.听This is where there are connections between the babies鈥� blood supplies and one twin gets a greater share of the blood supply than the other. Monochorionic twins are scanned every two weeks from 16 weeks to check for any signs of this developing.听听In some cased听twin-twin transfusion syndrome can be serious and if it is detected you will be referred to the听Fetal听Medicine Unit in Leeds for specialist advice. If you are carrying monochorionic twins and feel a sudden (鈥榦vernight鈥�) increase in the size of your pregnancy, your tummy becomes very听tight听or you suddenly become breathless you should contact your midwife or the hospital so we can check for twin-twin transfusion.听
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How听will I be looked after in the Antenatal clinic?听
The care you receive will depend on whether you are carrying monochorionic or diamniotic twins.听
Screening for Down鈥檚 Syndrome will be discussed with you by the screening coordinator or one of the doctors in clinic. This is covered in the information leaflet听multiple pregnancy.听
Your blood count will be taken at 20-22 weeks and again at 28 weeks to look for signs of anaemia.听
You will have a听fetal听anatomy scan to look for abnormalities in the way the twins are developing at 20 鈥� 22 weeks.听
If you are carrying听monochorionic diamniotic听twins you will be scanned at two weekly intervals from 16 weeks until delivery. This is to check for signs of twin-twin transfusion syndrome and for any differences in the way the twins are growing.听听
If you are carrying听dichorionic听dimaniotic听twins you will be scanned at four weekly intervals from 24 weeks to check how both twins are growing.听
You will be seen in the antenatal clinic after each ultrasound scan and the results will be explained to you.听
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When will my babies be delivered?听
Six out of ten women carrying twins will go into labour themselves before 37 weeks. There is an increased risk to the babies if the pregnancy is allowed to continue past 38 weeks.听
If you are carrying听dichorionic diamniotic听twins you will be offered delivery at 37 weeks.听
If you are carrying听monochorionic diamniotic听twins you will be offered delivery at 36 weeks.听
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What is the best way to deliver my twins?听
If the first twin is听head first听(cephalic) a vaginal delivery would usually be considered. Labour may happen spontaneously or you may be induced.听
If the first twin is not听head first听a caesarean would usually be听advised.听听
There is a risk of one or both babies showing signs of distress in labour. For this听reason听we recommend that we listen to both听babies听heart rates continuously during labour. Whist many twins deliver vaginally without any help there is an increased risk of operative vaginal delivery (ventouse or forceps) or caesarean section compared to women labouring with one baby.听
In some听cases听the second twin will be in a difficult position for delivery after the first twin has delivered. An obstetrician will be present at the delivery in these cases and may need to help turn your baby either by pushing it into a favourable position from the outside (external version) or feeling inside the womb to deliver it feet first.听
Occasionally after delivery of the first twin the second twin becomes distressed or is in a position where vaginal delivery is not possible safely. In these听situations听it may be safer to deliver the second twin by emergency caesarean section.听
A caesarean section carries operative risks and can make future pregnancies听more risky听so will only be advised if it is felt that this is the safest option. Recovery from a caesarean section usually takes longer than from a normal delivery.听
Your obstetrician will discuss the options for delivery with you in the antenatal clinic.听
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Can I breastfeed twins?听
It is possible to exclusively breastfeed twins for many听months听but the first few weeks can be challenging, having the right help and support is essential. All the midwives are fully trained in the skills necessary to support you. If you would like to speak to the Infant Feeding Co-ordinator before the birth of听your听 babies听or require extra help with feeding once they are born contact: Jo听Orgles听01423 555629听
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Postnatal Care听
Recovering from the delivery and looking after two babies can be tiring. The midwives will agree a plan with you to give you the support you need.听听
Mothers of multiple pregnancies are at increased risk of postnatal depression. It is important that you or your partner tell your midwife, health听visitor听or GP if you are feeling low or overwhelmed听
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Further Information听
TAMBA 鈥� Twins and Multiple Births Association听
2 The Willows,听Gardner Road, Guildford,听Surrey听GU1 4PG听听
Tel: (Twinline) 01483 304442 (10 am 鈥� 1pm and 7pm 鈥� 10pm everyday) Tel: (office) 01483 302483听
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Multiple Births Foundation听
Hammersmith House, Queen Charlottes and听Chelsea听Hospital,听Du Cane Road, London听W12 0HS听
Tel: 020 83833519听
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Twin to Twin Transfusion Syndrome Foundation听
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