The birth of more than one baby is always known as a multiple birth, whether there are two, three or more. One baby at a time is known as a singleton.
Multiple birth – the statistics
- one pregnancy in every 80 is a twin pregnancy
- one pregnancy in 8,000 is triplets
- one pregnancy in 800,000 is quads.
Twins – how pregnancy and birth are different
Twins (and more) are formed either by the egg splitting shortly after fertilisation identical twins) or by two or more eggs being fertilised by two or more sperm (non-identical or fraternal twins). Non-identical twins are slightly more likely to happen after a course of fertility treatment which stimulates ovulation, and which means more than one egg may be released. They can also happen when more than one fertilised egg is put into the uterus after in vitro fertilisation (IVF – test-tube pregnancy).
Twins will show up on the screen during an ultrasound scan. They may be suspected if your uterus is larger than expected at this stage of pregnancy.
The main concern with a multiple pregnancy, even if you are healthy and have no major problems, is that the minor discomforts of pregnancy may be heightened. That means (for example) more backache, fatigue, heartburn and nausea, constipation and piles. The increased weight gain and the excess of pregnancy hormones contribute to this. You’ll need lots of rest, especially later on in pregnancy and a healthy diet is particularly important.
If you are expecting twins, or more, you will receive more attention during pregnancy. The reasons for extra care include:
- a greater chance of high blood pressure, which needs careful observation and possible treatment
- the fact that twins, or more, are likely to be born before 40 weeks – 37 or 38 weeks is average for twins, but 25% of twin pregnancies lead to birth before 36 weeks
- a greater likelihood of birth problems
- Caesarean section may be necessary to speed up delivery or to deliver the second twin quickly. Less space in the uterus means one or both twins may be in a difficult, or impossible, position for a vaginal birth.
Triplet pregnancy is even more likely than twin pregnancy to end in a preterm or operative delivery (or both). Caesarean section is considered virtually inevitable for quads or quintuplets to control the delivery. Even so, while multiple pregnancy is hard work, and a multiple labour and delivery may be more of a challenge to everyone, especially you, the majority of twin and triplet births are as joyous and rewarding as any other, and many pregnancies and births are perfectly straightforward.
For some women, being told that they are expecting twins or triplets may come as a real shock and they may find it hard to cope with the thought of looking after more than one baby. You will need all the support you can get. There is special support for twin and multiple birth families and you should ask your midwife about local groups (see Further help). You will need plenty of help once your babies are born with things like bathing and nappy changing.
Twins in the uterus – how do they lie?
The best presentation of twins is with both lying head-down – ‘cephalic’ or ‘vertex’ – and this is the most common. However, pressure on space in the uterus means it’s also quite common for one or both babies to be breech (feet or bottom down). A transverse lie (baby across the uterus) is also a possibility and, if this is the case with the first presenting twin, a Caesarean section is inevitable. If the first twin has been born vaginally but the second twin is lying across the uterus, there may be an attempt to turn the second twin.
See the TAMBA website, the Twins and Multiple Birth Association for more information.