Monique Rainford

Recently, I had the pleasure of delivering lovely and healthy twin girls. The first born was more than a pound bigger than her sister. So far mom is handling her new additions expertly.

However she did very well, she had her fair share of challenges. Having twins can be an exciting and even desired prospect for some parents, but twin pregnancies carry higher risks than singletons (pregnancies with only one foetus).

The majority of twins are non-identical or fraternal twins. They arise from the fertilisation of two separate eggs. They are known as dizygotic twins. It is even possible for different eggs to be fertilised days apart by sperm from different men. Identical or monozygotic twins arise from the division of a single, fertilised egg. The timing of the division has a critical effect on the twins. For example, if the division occurs more than eight days after fertilisation, the twins may share one amniotic sac which is very dangerous for them. Conjoined twins result when the division occurs even later.

A woman is more likely to have twins if she was a dizygotic twin, as she gets older with a peak at age 37, and as the number of children she has increases. She is also more likely to have twins if she has had better nutrition or has used fertility treatments.

Birth weights

Twins are most easily diagnosed by ultrasound but if a woman's womb is much larger than expected at a particular point in pregnancy that may be suggestive of twins.

If a woman is carrying twins, she is more likely to have a miscarriage. In fact, she may be carrying twins very early in pregnancy but may lose one by the second trimester. Twins, especially monozygotic twins, are at a higher risk of having birth defects.

Twins tend to have smaller birth weights than singletons. This is mainly due to twins being born early (preterm) and sometimes the growth of one twin is much slower than the other. These differences can be due to different sized placentas (the organ providing the nutrition for the foetus) or if there is only one placenta, the nutrients and oxygen may not go equally to each twin.

About 50 per cent of twins deliver at 36 weeks of pregnancy or less. Women with twins or a higher number of foetuses are more likely to have preterm labour (labour before 37 weeks of pregnancy), preeclampsia (elevated blood pressure and urine protein in pregnancy), diabetes in pregnancy (gestational diabetes), placental abruption (the premature separation of the placenta from the womb) and her water breaking before term. She is also more likely to get a kidney infection and to have excessive bleeding after delivery.

Closer monitoring

Given these higher risks, a woman with twins needs closer monitoring in pregnancy and it is important that she cooperates with her physician. She needs to eat approximately 300 extra calories compared to a woman with only one foetus and she should gain about 35 to 45 lbs. If she develops diabetes, she should eat the recommended food and check her blood sugars frequently. She may require insulin or other medications to control her sugars. Good nutrition improves the health of her twin foetuses.

She may need several ultrasounds to monitor the growth of her twins, especially if one twin does not appear to be growing as well as the other.

A woman in some cases may have a vaginal delivery of her twins but this depends on the position of the twin that is closest to her cervix (the neck of the womb). Women with twins often require Caesarean section delivery.