Discovering you are expecting multiples is a surprise and shock to most, even if they were aware there was a chance! Most parents feel a sense of bewilderment: 'How are we going to cope?' 'What do I need?' 'How will this affect my pregnancy?' 'What are the risks?' 'What support is there?'
It is perfectly natural to be concerned and overwhelmed. Congratulations, you are going to be a multiple birth parent! Multiple birth pregnancies, just like multiple birth parenting, are much more involved and labour-intensive. The type of multiples you are expecting will dictate the type of antenatal treatment you will get and the preparation you will need to do.
Fraternal or dizygotic (two zygotes) twins develop when two separate eggs are fertilised and implant in the uterus. The genetic connection is no more or less the same as siblings born at separate times. They may look alike, or they may not. They can be made up of same sex multiples (boy and boy or girl and girl) or a mixture (boy/girl) of sexes. Likewise, triplets or quadruplets can be trizygotic or quadrizygotic. Fraternal twins are statistically the lowest risk multiples to have. Having their independent nourishment supply (the placenta) and housed in separate amniotic sacs, fraternal twins are like having two pregnancies simultaneously.
With fraternal twins, you will find your antenatal treatment will slightly differ to a singleton pregnancy. You will undergo a compulsory glucose tolerance test, there will be a growth reference check by way of an ultrasound at 28 weeks and sometimes beyond and the delivery due date will be brought forward to 38 weeks instead of 40 weeks with singleton pregnancies.
Identical or monozygotic (one zygote) twins form when a single fertilised egg splits into two genetically identical parts. The twins share the same DNA, thus they may share many similar attributes. However, since physical appearance is influenced by environmental factors and not just genetics, identical twins can actually look very different. Identical twin pregnancies will have the same basic treatment as fraternal twin pregnancies with some extra ultrasounds to check for Twin-to-Twin-Transfusion Syndrome and cord entanglement.
Higher Order Multiples (HOMs)
Triplets and more can be a combination of both identical and fraternal multiples. Triplets are most commonly a combination of monozygotic and dizygotic with a set of identical (2) and a fraternal (1) triplet. Triplets or more require more intense and consultative pregnancy. For more information on higher order multiple pregnancy and support, please visit our HOM pages.