"Multifetal pregnancies account for ~1% of all pregnancies but are seen in much higher numbers in populations where in vitro fertilisation (IVF) is a common practice."
"in vitro fertilisation (IVF): particularly use of ovulation induction agents"
"Also known as fraternal twins resulting from independent fertilization of two ova, and always result in dichorionic - diamniotic pregnancies. This feature alone cannot be used to distinguish dizygotic from monozygotic pregnancies as approximately 20% of monozygotic pregnancies will also be dichorionic-diamniotic (resulting in ~80% of all twin pregnancies being dichorionic-diamniotic). The most reliable sign of dizygosity on ultrasound is documentation of different sex fetuses."
"if twin pregnancy from in vitro fertilization (IVF): gestational age should be made from date of embryo transfer"
"if not: consider dating pregnancy using the larger fetus to avoid missing a situation of early intrauterine growth restriction in one twin"
"Also known as identical twins are due to fertilisation of a single ovum that then separates into two. Unlike dizygotic pregnancy, monozygotic pregnancies do not have maternal age, family history, or ethnic predisposition. The time at which this separation occurs determines the chorionicity and amnionicity of the pregnancy."
"Calculating due date (EDD)"
Expected headings
"Classification"
"Dizygotic twins"
"Monozygotic twins"
"Complications"
"Monochorionic complications"
"Monoamniotic complications"
"Ultrasound assessment of multi-fetal pregnancies"
"Determining chorionicity and amnionicity"
"Dichorionic"
"Monochorionic diamniotic"
"Monoamniotic"
"Calculating due date (EDD)"