Hello and welcome to the Zero to Finals podcast. My name is Tom and in this episode I'm going to be talking to you about multiple pregnancy.

And you can find written notes on this topic at zero to finals.com slash twins or in the antenatal care section of the Zero to Fin finals, obstetrics and gynecology book.

So let's get straight into it.

Multiple pregnancy refers to a pregnancy with more than one fetus.

The incidence of multiple pregnancies increased with the development of fertility treatment.

Let's talk about the types.

There are some key definitions to be familiar with relating to twin and multiple pregnancies.

Monozygotic refers to identical twins, and these originate from a single zygote.

A zygoat is a single cell formed by an egg and a sperm.

Dizygotic refer to non-identical twins which originate from two different zygotes.

Monoamniotic refers to a single amniotic sac.

Di-amniotic refers to two separate amniotic sacks.

Monochorionic refers to when the twins or multiple pregnancies share a single placenta.

Dicorionic refers to when there's two separate placentas.

The best outcomes for twin pregnancies are di-amniotic, di-corionic twin pregnancies,

as each fetus has their own supply of nutrients.

Let's talk about making the diagnosis. Multiple pregnancy is usually diagnosed on the booking

ultrasound scan. Ultrasound is used to determine the gestational age, the number of placentas, which is the corionicity,

and the number of amniotic sacks, which is the amnionicity,

and the risk of Down syndrome as part of the combined test for down screening.

When determining the type of twins using an ultrasound scan,

di-corionic di-amniotic twins have a membrane between the twins

...