How common are multiple pregnancies?
What causes multiple pregnancy?
You are more likely to carry multiple babies if you got pregnant using IVF. Women in their 30s and 40s are more likely to get pregnant with twins because they are more likely to release more than 1 egg during ovulation.
You’re also more likely to carry twins if non-identical twins run on the mother’s side of the family. Fathers can carry the gene too and pass it to their daughters. Identical twins usually do not run in families.
When will I find out if I’m having more than 1 baby?
It’s usually possible to find out for certain if you’re having twins at your first ultrasound scan. This is part of your routine antenatal care at around 11 to 14 weeks of pregnancy. You may already know that you are having more than one baby/babies if you were having IVF.
What types of twin and triplet pregnancies are there?
If you are carrying more than 1 baby, your healthcare team will also find out from your scan whether your babies share a placenta and/or amniotic sac. This is because it will have an impact on what type of care you will have in pregnancy and when you give birth.
Types of twins
- Dichorionic diamniotic twins (DCDA) – each baby has a separate placenta and amniotic sac.
- Monochorionic diamniotic twins (MCDA) – the babies share a placenta but have separate amniotic sacs.
- Monochorionic monoamniotic twins (MCMA) – the babies share a placenta and amniotic sac.
Types of triplets
- Trichorionic triamniotic triplets – each baby has a separate placenta and amniotic sac.
- Dichorionic triamniotic triplets – 1 baby has a separate placenta and 2 of the babies share a placenta. All 3 babies have separate amniotic sacs.
- Dichorionic diamniotic triplets – 1 baby has a separate placenta and amniotic sac, and 2 of the babies share a placenta and amniotic sac.
- Monochorionic triamniotic triplets – all 3 babies share 1 placenta but each has its own amniotic sac.
- Monochorionic diamniotic triplets – all 3 babies share 1 placenta. 1 baby has a separate amniotic sac and 2 babies share 1 sac.
- Monochorionic monoamniotic triplets – all 3 babies share a placenta and amniotic sac.
Will my babies be identical?
If your babies share a placenta, it usually means they are identical. If they don’t share a placenta, they may be identical or not. The most accurate way to tell if twins are identical is through a DNA test. This can only be done after your babies are born (unless there are concerns in your pregnancy and your DNA needs to be checked).
Most babies do not share a placenta.
What are the complications associated with multiple pregnancy?
If you are having multiple babies, there are some complications to be aware of. Keep in mind that you should have extra care throughout your pregnancy and there is lots of support available, for example from the Twins Trust.
Most women carrying twins, triplets or more will go on to have healthy pregnancies and healthy babies.
Increased pregnancy symptoms
You may have stronger pregnancy symptoms if you are having a multiple pregnancy. This is because of the increase in pregnancy hormones. For example, you may have:
- severe morning sickness that may last longer than average (occasionally past the first trimester)
- persistent heartburn and indigestion, especially towards the second half of pregnancy
- increased tenderness in your breasts.
As your pregnancy progresses, the increased pressure from your womb onto your tummy may cause swelling in your ankles and varicose veins to develop in the legs and vulva (the external female sex organs).
You may also have shortness of breath, backache, pelvic pain and exhaustion as your body is coping with the demands of carrying a heavier load. Talk to your midwife if this is happening for you. They may be able to refer you to a physiotherapist.
Every pregnancy is different, so you may not experience all of these symptoms or may only have minor problems. Remember that your team is there to help you, so talk to your midwife or doctor if you have any concerns.
If you are carrying more than 1 baby, you are at higher risk of developing anaemia. Your midwife will give you the same advice as other pregnant women about having a healthy, balanced diet and what vitamins (supplements) to take during pregnancy. But you can prevent and treat anaemia by making sure that you are eating iron and folate-rich foods, as well as take daily folic acid supplements.
You will have a blood test to check for anaemia at your booking appointment, at 20-24 weeks and at 28 weeks of pregnancy. But it may be helpful to familiarise yourself with anaemia symptoms and tell your GP or midwife at any time if you think you have it.
Pre-eclampsia is a condition that only affects pregnant women. It is a combination of raised blood pressure (hypertension) and protein in your urine (proteinuria). If you are having twins or triplets and have any other risk factors for pre-eclampsia, you may be advised to take low-dose aspirin from 12 weeks of pregnancy onwards to reduce the risk.
Women carrying more than 1 baby are more likely to develop gestational diabetes. You will be offered a screening test for this during your pregnancy.
Some people are very excited to find out they are having twins or triplets. Others may be shocked or feel anxious about what this means for them. It’s natural to feel nervous or overwhelmed. Having a baby is a life changing event that is incredibly exciting, but it can also be stressful and exhausting. If you are having a multiple pregnancy, it is possible that you may have to cope with a difficult pregnancy, labour and birth.
This may be why women with multiple pregnancies are more likely to experience antenatal depression.
Antenatal depression is when you feel sad all the time for weeks or months during your pregnancy. The condition can vary from mild to severe and can affect women in different ways.
Depression in pregnancy is common and nothing to be ashamed of. It’s important to tell your midwife or doctor how you feel. They will focus on helping you find the right treatment and support so you can take care of yourself and your baby.
Intrahepatic cholestasis of pregnancy (ICP)
Intrahepatic cholestasis of pregnancy (ICP) can be more common in multiple pregnancies. It is a potentially serious liver disorder that can develop in pregnancy. The main symptom is itching, usually without a rash.
Deep vein thrombosis (DVT) is a serious condition where a blood clot forms in a deep vein in the body, usually in the leg. DVT isn't common in pregnancy. But pregnant women at any stage of pregnancy, and up to 6 weeks after the birth, are more likely to develop DVT than non-pregnant women of the same age. Your risk of developing DVT during pregnancy is even greater if you are carrying multiple babies.
Call 111 or arrange an urgent appointment with your GP if you have these symptoms in your leg:
- throbbing or cramping pain in 1 leg (rarely both legs), usually in the calf or thigh
- swelling in 1 leg (rarely both legs)
- warm skin around the painful area
- red or darkened skin around the painful area
- swollen veins that are hard or sore when you touch them.
Complications in labour
You may be more likely to be offered an induction (process to bring on labour), need a caesarean section or have an assisted birth to deliver your babies. There is also a higher chance of bleeding more heavily than normal after birth. This may sound a bit scary, but your doctors and midwives are trained to deal with these situations. You will also have a chance to talk to your team about your birth plan a few weeks before you are due to have your babies.
For your baby
Problems with growth
If you’re having twins or more, this increases the chance of the placenta not working as well as it should. This can affect the babies’ growth and development.
Most twin, triplet or more babies will be slightly different in size, but sometimes 1 baby is significantly smaller than the other/s. This is called ‘selective’ fetal growth restriction. Selective fetal growth restriction occurs in 10-20% of multiple pregnancies.
Find out more about fetal growth restriction. Your team will monitor your babies’ growth during your pregnancy.
Most twins and triplets are born prematurely. This can happen spontaneously (on its own). This happens in 60% of twin pregnancies and 75% of triplet pregnancies. If your baby is born early, they may need special care because they may not be fully developed. Find out more about premature birth.
You are even more likely to give birth early if you have given birth early before. Find out more about risk factors for premature birth.
Women who are pregnant with 1 baby may be offered treatments to prevent premature birth. These include progesterone pessaries, a cervical stitch or an arabin pessary. However, these are not routinely offered to women carrying multiple babies. Bed rest is also not routinely advised. Your doctor or midwife can give you more information.
You may be offered a medication called corticosteroids during your pregnancy to help your baby’s lungs develop more quickly. This can reduce the risk of complications associated with giving birth prematurely.
Twin-to-twin transfusion syndrome (TTTS)
Twins sharing a placenta (monochorionic pregnancies) also share the same blood supply. In around 15 in 100 monochorionic twin pregnancies, the blood flow may be unbalanced. This means that 1 baby receives too little blood and has a low blood pressure, while the other baby receives too much blood and has a high blood pressure. This is called twin-to-twin transfusion syndrome (TTTS).
You will be monitored with frequent scans for signs of TTTS. It can be mild and may not require any treatment, or it can be serious, in which case you will be offered treatment in a hospital with specialist expertise.
It’s important to be aware of the symptoms of TTTS and to contact your midwife or maternity unit straight away if you have any concerns.
The Twins Trust has more information about TTTS, including symptoms to look out for.
Sadly, losing a baby is more common for women carrying multiple babies. This may be due to complications arising in the twin pregnancy like chromosome abnormalities, complications of having a shared placenta such as TTTS, or selective fetal growth restriction. Premature birth and the associated complications may also increase the risk. This can be extremely difficult. If you have another baby that survives, this may cause some very complicated feelings.
Tommy’s is here to help. We have information and support for anyone who has experienced the loss of a baby. You can talk to a Tommy’s midwife for free, Monday-Friday, 9am-5pm. You can call them on 0800 0147 800 or email [email protected]. All our midwives are trained in bereavement support and will be able to talk to you about what you’re going through. You can also join the Tommy’s Support Group on Facebook.
The Twins Trust also run a bereavement support group.
What will my antenatal care be like?
It’s recommended that you have care from a specialist team of doctors and midwives who are experts in managing twin and triplet pregnancies. This team may also include support from a mental health professional, a women’s health physiotherapist, an infant feeding specialist and a dietitian. This team should be able to give you all the advice you need about:
- antenatal and postnatal mental health and wellbeing
- nutrition in pregnancy
- the potential complications associated with multiple births
- your birth choices
- feeding your babies
The advice for keeping healthy in pregnancy is similar whether you're expecting twins, triplets or just 1 baby. Eating a healthy, balanced diet, doing regular exercise and drinking lots of fluid will help.
The Twins Trust have developed a care pathway that covers the level of care you should be offered from the time of your first hospital scan, in addition to the routine care that is offered to all women during pregnancy. Find out more.
Having a multiple pregnancy means that you will need more antenatal appointments than women carrying 1 baby. This includes extra appointments with specialist doctors. You will also be offered extra ultrasound scans to monitor your babies’ growth more closely.
It's important to attend all your antenatal appointments so your maternity team can keep a close eye on you and your babies.
If you’re having twins
If you are having an uncomplicated twin pregnancy where the babies each have their own placenta (dichorionic diamniotic), you will be offered ultrasound scans about every 4 weeks from 20 weeks of pregnancy.
If you are having an uncomplicated twin pregnancy where the babies share a placenta (monochorionic diamniotic), your pregnancy will be monitored more closely. You will be offered scans every 2 weeks from 16 weeks of pregnancy
If you’re having triplets
If you are having an uncomplicated triplet pregnancy where each baby has their own placenta (trichorionic triamniotic),you’ll be offered ultrasound scans every 4 weeks from 20 weeks.
If any of your babies share a placenta (dichorionic triamniotic or monochorionic triamniotic), your pregnancy will be monitored more closely. You will be offered a scan every 2 weeks from 16 weeks of pregnancy.
If you are having twins or triplets that share an amniotic sac
If you’re having monochorionic monoamniotic twins, or dichorionic diamniotic, monochorionic diamniotic or monochorionic monoamniotic triplets, you will have care in a specialist fetal medical centre. You’ll be cared for by a healthcare team that are expert in managing complicated multiple pregnancies.
If you have complications in pregnancy
If you have any complications in pregnancy, you will have a bespoke care plan that is specific to what problems you are having.
Can I still have screening for Down’s syndrome and other conditions?
Like all women, you will be offered a scan at about 11–14 weeks to screen for chromosomal conditions such as Down's syndrome, Edwards' syndrome and Patau's syndrome.
If you are pregnant with triplets, there is a higher chance of chromosomal conditions. Your healthcare professional should give you more information about this and what your options are for screening. They will also talk to you about what happens if 1 or more of your babies is found to have a high chance of having one of these conditions.
All pregnant woman are also offered another scan at around 20 weeks to look at their babies’ physical development.
Getting more support
You can contact the Twins Trust on their Twinline, 0800 138 0509. This free, confidential service is offered between 10am and 1pm and again at 7pm until 10pm, Monday to Friday. Alternatively, you can email [email protected]
Our midwives are available to answer any questions you might have or even just to chat if you need to talk about the tests you will have. Our support line is open Monday-Friday, 9am-5pm – call us on 0800 014 7800. Or you can email [email protected]
The charity Antenatal Results and Choices offers non-directive information and specialised support for people who have received a diagnosis after antenatal testing. They can help you make sense of what you’ve been told. Its helpline is answered by trained staff:
- Monday-Friday, 10am-5.30pm
- on 0845 077 2290 (or 020 7713 7487 from a mobile)
- [email protected]
If you are carrying multiple babies you'll be advised to deliver earlier than your due date. Here's more information about your options for where, how and when to give birth.
Some women have a feeling that they are having twins (or triplets) before they find out for sure. If you’ve been wondering, there are sometimes signs that you may be carrying more than 1 baby.
NHS Choices. Pregnant with twins. https://www.nhs.uk/conditions/pregnancy-and-baby/what-causes-twins/ (Page last reviewed: 21/05/2019 Next review due: 21/05/2022)
Royal College of Obstetricians and Gynaecologists (2016) Multiple pregnancy: having more than one baby. https://www.nhs.uk/conditions/pregnancy-and-baby/antenatal-care-twins/
Macdonald, S and Johnson G (2017) Mayes’ Midwifery, Elsevier, London
The American College of Obstetricians and Gynecologists (2019) Multiple Pregnancy: Frequently asked questions. https://www.acog.org/patient-resources/faqs/pregnancy/multiple-pregnancy
NICE (2019). Twin and triplet pregnancy. National Institute for health and care excellence https://www.nice.org.uk/guidance/ng137
NHS Choices. Obstetric Cholestasis. https://www.nhs.uk/conditions/pregnancy-and-baby/itching-obstetric-cholestasis-pregnant/ (Page last reviewed: 02/08/2019 Next review due: 02/08/2022)
NHS Choices. Deep vein thrombosis (DVT) in pregnancy. https://www.nhs.uk/conditions/pregnancy-and-baby/dvt-blood-clot-pregnant/ (Page last reviewed: 27/03//2018 Next review due: 27/03/2021)Hide details
ℹLast reviewed on July 24th, 2020. Next review date July 24th, 2023.
By Michael Ray Overby (not verified) on 2 Aug 2017 - 02:38
Hello to Tommy's Midwives...
I & 17 women run MoDi Twins & MoDi Twins Pregnancy, support groups on Facebook for women involved in MCDA gestation. It's great to see you give mention to the #1 killer of twins In Utero. We deeply appreciate that. Let me tell you a couple things that aren't readily apparent, or possibly just don't get discussed.
First let's talk about that vessel imbalance. That is, in point of fact, what is Behind TTTS , but in a rather Markedly different way than may be Portrayed.
TTTS is, Firstly, a disorder of Runaway Growth of the placentation. One may believe that nutrient rich blood is Stolen by Recipient Twin & expropriated for her own use (Evil Twin!), but this is not at all what is happening. A little discussion on the placenta itself thus becomes necessary... For a Long Time, many believed that Placenta Grew Baby under it's Direction. Placenta would Size Up & tell baby to Get Bigger, using Growth Hormones. This theory works Fine and Dandy,& may have gained Full Acceptance if it weren't for All those Pesky MoDi... Twins, with a Shared Placenta... When we look at those, all kinds of Inconveniences pop up.
Placenta is known now to be a fast responding organ. Baby senses Low Fluid, her Adrenal Complex begins to Shed VEGFR-ES, a growth hormone for the placenta that is a request for More Fluid from it.
Works Beautifully, & in a Most Elegant Fashion.
Consider now please Two Babies, plumbed into a Shared Placenta, with Shared Circulation across said Placentation. Consider a Pair that is "Growing Normally", of nearly equal Size & Weight. Each baby signals for placental growth as she sees a Water Shortage. No Problem.
THEN, a vessel grows across the placenta, sending more fluid to one twin, without
a Corresponding one growing in the opposite direction.
What happens then?
The twin that is losing fluid, becomes the Donor. Due to the Transfusion happening from that vessel growing.
No Problem, she signals for placental growth.
Problem: Her side of the Placentation is Dried Out. It tries to make more fluid but cannot grow very well.
Additional Problem: Recipient's side of the placentation is Ideal for growth, & much more fluid capacity is engaged, which makes a whole lot more fluid available for Recip Twin, that she Does Not Need. That she Did Not Steal either.
If this state continues & no blood vessel to balance the state of the placental flow balance grows, or unless Shred Circulation is Curtailed by Laser, TTTS will continue until one or both twins have died.
By Midwife @Tommys on 2 Aug 2017 - 09:47
Hi Michael, thank you for your comment and support. We really appreciate you sharing your knowledge for our Tommy's followers/supporters/families.
All the best :)
By Natalie Gilbert (not verified) on 2 Feb 2017 - 23:00
I too went through the horror of being diagnosed with ttts. It was at 16 weeks. One baby had more fluid around him than the other. I had regular scans every week. Then at 19 weeks I went from stage 1 to stage 3 in one week and had to have laser surgery to which I felt everything. They burst a blood vessel going on and said they would have to kill one of my babies. It was devastating. Luckily they stopped the bleed and things resumed back to normal. All fluids the same and blood was the same to both baby boys. To my horror my waters broke at 23 weeks. I was transferred to the Rosie hospital in Cambridge. And all the doctors gave them no hope in hell in surviving. Gave me an approx weight for both. At 24 weeks I gave birth naturally. Charlie the smallest twin died in my arms whilst i was still giving birth to his brother. Alfie died shortly after although he was quite bigger. The doctors did everything they could. I'm not sure the boys were ready for this cruel world and wanted to be together. The loss of them still dooms me to this day and apart of me went down with them when i buried them. They will always be mummies angels. And they live on in my two boys that i have here. They love there brothers and there's never a day that goes by that we don't think of them.
By Midwife @Tommys on 3 Feb 2017 - 10:28
I am so terribly sorry to hear what you have been through with the loss of your two boys Charlie and Alfie, I cannot even begin to imagine how this has been for you. If we can support you in anyway then please do email us in confidence, [email protected] or call our midwife line on 0800 0147 800. Take care, Tommy's midwives.