Twins arrive in 1.5% of all births, with triplets or even more babies accounting for many fewer deliveries at 0.02%. The numbers of twin pregnancies has initially risen over the past few decades due to increases in IVF rates, however this has decreased with more regulation with IVF and the number of twins or more has fallen. Other reasons for twins or more include fertility medications and older mothers having children. The higher the
number of babies in multiple pregnancies, the higher risk for both the baby and the mother.
Twin (and other multiple) pregnancies are considered high-risk pregnancies. As well as discomforts associated with carrying multiple babies (back aches, pelvic pain, increased swelling), there is a predisposition to develop many of the complications of pregnancy such as high blood pressure (preeclampsia) and diabetes. The babies are also at higher risk of being smaller than expected and premature and may need to go to neonatal intensive care for a period after birth. Indeed a dizygotic twin pregnancy (where there are two separate eggs forming two embryos – “non-identical twins”) has an average gestation period of 38 weeks (compared to the 40 weeks of a singleton pregnancy). Monozygotic twins (a single egg that splits into two embryos after fertilisation – “identical twins”) are even higher risk again and need to be closely monitored during the pregnancy. A complication called twin-twin transfusion syndrome (TTTS) may occur due to the shared placenta and can be life threatening. Overall, if you have a multiple pregnancy you can be assured of frequent visits to your obstetrician and many ultrasound scans!
Higher order multiples are delivered by caesarean, whereas twin pregnancies may be delivered vaginally or via a caesarean. Factors that are important in this decision include the type of twin pregnancy (if there is a shared placenta and amniotic sac a caesarean will be recommended), the way the first twin is facing (head down is best), the size of the twins (particularly in relation to each other) and whether the mother has had a caesarean delivery previously. When planning for a vaginal delivery an epidural may be recommended in case of complications with delivery of the second twin. Expect to have many health professionals and equipment in the room at the time of delivery: there will be your obstetrician, two or more midwives as well as paediatricians to help when the babies are born.
It can be overwhelming to discover twins (or more!) on the first ultrasound, particularly if you already have children, but there are support groups to access and lots more information from resources such as the Australian Multiple Births Association to help you as your family grows!