Expecting Twins: What to Know About a Multiple Pregnancy

Finding out you are expecting twins is one of those moments that tends to stop time. The joy and the overwhelm often arrive simultaneously, followed quickly by a lot of practical questions.

Types of twin pregnancy

**Dichorionic diamniotic (DCDA)** twins each have their own placenta and amniotic sac. These are the lowest-risk twin pregnancies and include all fraternal (non-identical) twins and about a third of identical twins.

**Monochorionic diamniotic (MCDA)** twins share a placenta but have separate amniotic sacs. These are always identical. They require more frequent monitoring due to the risk of twin-to-twin transfusion syndrome (TTTS), where blood moves unequally between twins via shared blood vessels.

**Monochorionic monoamniotic (MCMA)** twins share both a placenta and an amniotic sac. This is the rarest and highest-risk type and typically requires hospital admission in the third trimester.

Care during a twin pregnancy

Twin pregnancies are classified as higher risk and cared for by a consultant-led team alongside a specialist fetal medicine unit. You will have more frequent scans, typically every two weeks from 16 weeks for MCDA twins. Your team will monitor growth, fluid levels, and blood flow closely.

What changes physically

The discomforts of pregnancy, including nausea, fatigue, heartburn, back pain, and swelling, often arrive earlier and more intensely in a twin pregnancy. The uterus reaches the size of a full-term singleton pregnancy around 28 weeks.

A twin pregnancy support band becomes important earlier than in a singleton pregnancy.

Birth

Most twins are born before 37 weeks. The timing and mode of birth depends on the type of twin pregnancy, the position of the babies, and the preferences of the parents and team. Around 40% of twin births in the UK are vaginal. MCDA and MCMA twins typically require a caesarean or very specialist vaginal birth.

Preparing practically

Two of everything adds up. Prioritise the things you cannot do without: two sleep spaces, two sets of feeding equipment, and a double pram that fits through your front door.

The rewards

Parents of twins consistently describe the bond between their children as one of the most extraordinary things they have ever witnessed. The early months are genuinely harder. The joy, say parents who have been through it, is indescribable.