twin (redirected from twinned)

twin (twin) one of two offspring produced in the same pregnancy and developed from one oocyte (monozygotic) or from two oocytes (dizygotic) fertilized at the same time.

Twins. (A), The most common type of monozygotic twinning, with division of the inner cell mass of the blastocyst resulting in separate amnions but a single chorion and placenta; (B), a rare form of monozygotic twinning, with complete division of the embryonic disc resulting in two embryos in a single amniotic sac with a single placenta and chorionic sac; (C), monozygotic twinning with division occurring between the two-cell and morula stages to produce identical blastocysts, resulting in separate amniotic and chorionic sacs and either separate (shown) or fused placentas; (D,E), dizygotic twinning, with (D) or without (E) fusion of the placenta and chorion.

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allantoidoangiopagous twins  twins united by the umbilical vessels only.

conjoined twins  monozygotic twins whose bodies are joined to a varying extent.

diamniotic twins  twins developing within separate amniotic cavities; they may be monochorionic or dichorionic.

dichorionic twins  twins having distinct chorions, including monozygotic twins separated within 72 hours of fertilization and all dizygotic twins.

dizygotic twins , fraternal twins, heterologous twins twins developed from two separate oocytes fertilized at the same time.

identical twins  monozygotic t's.

impacted twins  twins so situated during delivery that the pressure of one against the other prevents simultaneous engagement of both.

monoamniotic twins  twins developing within a single amniotic cavity; they are always monozygotic and monochorionic.

monochorionic twins  twins developing with a single chorion; they are always monozygotic and may be monoamniotic or diamniotic.

monozygotic twins  two individuals developed from one fertilized oocyte; they have identical genomes.

omphaloangiopagous twins  allantoidoangiopagous t's.

Siamese twins  conjoined t's.

similar twins  monozygotic t's.

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twin (twn)

n.

One of two offspring born at the same birth.

adj.

1. Being two or one of two offspring born at the same birth.

2. Consisting of two identical or similar parts; double.

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twin

Etymology: AS, twinn, double

either of two offspring born of the same pregnancy and developed from either a single ovum or from two ova that were released from the ovary simultaneously and fertilized at the same time. The incidence of twin births is approximately 1 in 80 pregnancies. Kinds of twins include conjoined twins, dizygotic twins, interlocked twins, monozygotic twins, Siamese twins, and unequal twins. See also Hellin's law.

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twin

one of the two same-age fetuses in the one pregnancy. See also twins, twinning.

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twin

One of 2 gestational products that develop during a single intrauterine gestational period. See Dizygotic twin, Monozygous twin, Higher multiples, Partial twin, Siamese twin, Vanishing twin. Cf Siamese twins.

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Patient discussion about twinned.

Q. anything a mother should know about the last period of twin pregnancy? she is in her 7th month and starting to be real heavy... her legs hurt like crazy. anything to help her with?

A. thanks for all the information! I hope everything will go on well...

Q. Is there a bigger risk of autism for the newborn in twin pregnancy?

A. thanks Dominicus!
you're great...

Q. How do I know whether I will get twins or not? Twins have always fascinated me and I cannot wait to get pregnant and have twins. My husband has already bought identical dresses hoping that we will be expecting twins shortly. As I am conceived now that I am pregnant, I am going for a test tomorrow. How do I know whether I will get twins or not?

A. do you have identical twins in your family? if so the chances of you having twins is greater, anyway, checking it out can be done only by ultrasound screening. only then they can see if there are two heartbeats and see two fetuses.