Miriam's casebook - Twins
Karen was told she was expecting twins when she had an ultrasound scan at 14 weeks. Mother of two, she knew from the beginning that there was something different about this pregnancy. For one thing, she was constantly sick in the first couple of months, which she hadn't been with her previous two pregnancies. She also looked huge - at three months she looked about five! Both previous pregnancies had been normal, except for oedema (swelling of feet and ankles) in the last month.
Suspecting a multiple pregnancy
Once they'd got over the initial surprise of finding out that they were expecting twins, Karen and her parnter, Joe, were delighted, if a little apprehensive. Their first concerns were for the wellbeing of Karen and the twins throughout the pregnancy, and then how they would manage to cope with the extra responsibilities that having two babies would bring.
Many women guess early on that there's something different about their pregnancies when they're carrying twins. Size is often a clue, as well as the shape - twins tend to push the abdomen out sideways as well as forwards. Twins can be diagnosed by week six of the pregnancy with an ultrasound scan.
Experiencing a twin pregnancy
Some women sail through a twin pregnancy with very few or no side effects. Some don't. The extra physical stress of carrying two babies can increase feelings of tiredness and sickness as your body adjusts. Also, twin pregnancies need to be watched carefully for raised blood pressure, anaemia, oedema (swelling of feet and ankles), and pre-eclampsia. Like all expectant mothers of twins, Karen will go to her antenatal clinic more often than a woman expecting one baby. Her doctor will watch for oedema happening again, and may get her into hospital if she seems likely to develop pre-eclampsia. She needs a good, high-protein diet.
Sheer size can be a problem in later pregnancy, and it can be hard to get comfortable. I suggested to Karen that she might find that being in water helps as it will support her weight. Gentle swimming would be fine as long as her doctor agrees. She might also like to hire a birthing pool (see Useful addresses) as an extra large bath in which she can relax. Making love is usually fine, although Karen should follow her doctor's advice and check straight away if she has any discharge or bleeding or if she has contractions.
A twin labour
I suggested to Karen that she get as much rest as she can during her pregnancy. Among women expecting twins those who don't have enough rest are much more likely to go into premature labour than those who've had more rest from the fifth month. Whatever work you do during a twin pregnancy, including caring for young children, make sure it isn't too strenuous. I advised Karen to try to arrange some extra help with her older children when she can, and have at least three hours' bed rest a day.
A twin labour is always managed in hospital because of the potential risks involved. Doctors and midwives are highly sensitive to the difficulties that can occur, so 30 minutes is the most they'll allow between births. The second twin is always monitored closely for any signs of distress. There may have to be an emergency Caesarean section if a twin appears to be in danger.
Identical or not?
One-third of all twins are identical. They are always the same sex and usually share the placenta, although this depends on how late the egg splits. Half of non-identical (or fraternal) twins are boy-girl pairs and half are same sex. Their placentas are separate, but may be fused together. The incidence of identical twins appears to be completely random, while non-identical twins often run in families, inherited through the mother's side. The likelihood of having non-inherited, non-identical twins rises until a woman is in her mid-30s, then drops again. It also seems to be higher if she's tall, well built, and conceives easily. The chances of having non-identical twins also appear to increase with each subsequent child.
Birth of twins
A twin pregnancy and birth is different in several important ways. Twins have a shorter gestation period than single babies - they're normally born at 37 weeks rather than 40 weeks. This is mostly because there's just not enough space in the mother's womb, although other external factors are also important. Because they have a shorter gestation period, twins weigh less than single babies.
There are extra risks for the second-born: she has to go through the intense contractions of expulsion twice over. The second twin may also suffer from a lower oxygen supply to the placenta because the mother's uterus will start to contract once the first twin has been delivered.
Miriam's top tips
Every twin pregnancy is different, but there's no doubt that a multiple pregnancy puts an extra strain on a woman's body. My advice is to:
- ask your doctor for an early scan if you experience symptoms early on in your pregnancy that lead you to suspect you might be carrying twins
- make sure that your diet is nutritious and high in iron and protein (see Eating Well)
- rest when you can during your pregnancy, especially after the fifth month. The more daily rest you manage, the less likely you are to go into premature labour.
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