Are identical twins 100% the same? The type of placenta nurturing identical twins plays a significant role in the development of complications in multiple gestation. And about 1% of identical twins have a single placenta and a single sack. While it is scary, there is no way to prevent it. 20 Are monozygotic or The technical name for this is dichorionic. Monozygotic is identical as they often have similar appearances and characteristics. twin pregnancy. Identical twins are always the same sex (except in rare cases) and blood type. To further elaborate on /u/mtlggy 's comment, identical twins come from one egg that splits into two, which is why they are in the same placenta. Monozygotic or identical twins (also called "real" twins) can have individual or shared placentas. Identical twins are the result of one egg splitting post-fertilization, but the timing of the split determines if the twins will each have their own sacs and placentas (split on day 1-3, called di/di twins), share a placenta (split on day 4-8, called mo/di twins), share an amniotic sac and placenta (split on day 8-13, called mo/mo twins) or be Around 3.3% of Americans are twins, but only .3% are identical. Fraternal nonidentical twins develop from two separate fertilized eggs. I am also started to show. These twins often share a liver. Identical Triplets (Monozygotic): Identical triplets occur when an egg splits after being fertilized and then splits again and so have nothing to do with assisted fertility treatment they are completely spontaneous. Pathology. Non-identical (dizygotic) twins happen when 2 separate eggs are fertilised and then implant into the womb (uterus). Note: Most cases, twins turn out to be fraternal or non-identical. Do identical twins have placentas? Identical twins who have separate placentas are somewhat less similar than identical twins who share a placenta. Identical twins can also happen in women who undergo fertility assistance methods. 1 The fetus begins developing fingerprint patterns in the early weeks of pregnancy. Within identical types of twins there are different categories, and these categories depends upon what they share in the womb. They come from the same egg and implant together. In a dichorionic twin pregnancy. In rare cases, they share both the placenta
About a third of identical twins have two placentas. twin pregnancy. There is no real explanation as to why eggs (zygotes) split. It is important to note that twins who share a placenta and sac (Mo Mo or Mono Mono twins) are in the highest risk category. If the identical twins share a placenta they are at a higher risk of having twin-to-twin transfusion syndrome. faithhopelove22. Twins are two offspring produced by the same pregnancy. Identical twins can have their own, or share both the outer sac (chorion) and the inner sac (amnion): 1 chorion, 2 amnions, 1 placenta (most common) roughly 65-70%. These are monochorionic diamniotic or MCDA twins. Di di twins are Monoamniotic twins are always monochorionic and are usually termed Monoamniotic-Monochorionic ("MoMo" or "Mono Mono") twins. Contradicting nearly all the medical textbooks, doctors have proven for the This is a risk due to a shared placenta. Meanwhile, fraternal twins result when two eggs are released by the mother (instead of just the "usual" one), which is In some cases, they have two placentas. Non-identical, also known as dizygotic twins, develop when two eggs are fertilized by two sperms. There are two types of twin situations where your babies can be in different sacs, separated by whether they share a placenta, (mono di) or have separate placenta (di di.) Twins are two offspring produced by the same pregnancy. Non-identical twins have separate placentas, amniotic sacs, and umbilical cords. share unequal amounts of the placenta's blood supply resulting in the two fetuses growing at different rates. This is only possible with identical twins. Non-identical twins. Twins can be either monozygotic ('identical'), meaning that they develop from one zygote, which splits and forms two embryos, or dizygotic ('non-identical' or 'fraternal'), meaning that each twin develops from a separate egg and each egg is fertilized by its own sperm cell. Fraternal twins have separate placentas and umbilical cords. If the zygote takes from four to eight days to divide, the twins share a common placenta (monochorionic) and the membrane that separates the fetal twins two amniotic sacs is thin (diamnionic). Twins are mainly monozygotic or dizygotic. Non-identical twins form from two completely separate eggs which are fertilised by two completely separate sperm. If the identical twins share a placenta they are at a higher risk of having twin-to-twin transfusion syndrome. They share the same genetic composition and placenta. Want to Know More? Identical twin/triplets may share a placenta or an amniotic sac or they may have separate placentas and sacs. They share the placenta, but have two separate umbilical cords.Monoamniotic twins develop when an embryo does If a fertilised egg splits only partially into two what happens? No, identical twins are genetically identical, so are always the same sex. Duh. If your first ultrasound scan is done before 14 weeks, it should be possible to tell accurately what kind of placenta your twins have. While fraternal twins (2 eggs and 2 sperm) are always surrounded in their own sacs and have their own individual placentas , 70% of identical twins may end up sharing a single placenta .
One Placenta. Non-identical twins are uniquely separate individuals who just happen to be gestating at the same time and place as each other. They came from the same egg and--depending on when "the split" happened--will determine whether or not they have the same sac or 2. Monozygotic multiples form from a single egg and sperm combination that I am 10 weeks pregnant with identical twins sharing the same placenta, but two sacs. Most commonly, the egg will split around 4-5 days after fertilization. These twins are formed independently. Non-identical twins form from two separate eggs which are fertilized by two completely separate sperm. They may or may not share a placenta. Can identical twins have separate sacs? 2 Identical twins are known scientifically as monozygotic twins.. Depending on when the split occurs will determine if the twins share a placenta, with either one or two chorions and amnions, or if prenatal environments Which of the following is TRUE regarding heredity It is impossible to say what percentage of an individual's personality or intelligence is inherited While fraternal twins (2 eggs and 2 sperm) are always surrounded in their own sacs and have their own individual placentas, 70% of identical twins may end up sharing a single placenta. Identical twins do not have identical fingerprints, even though their identical genes give them very similar patterns. In most cases, identical twins share one placenta, but have separate amniotic sacs. Doctors do not routinely test non placenta sharers for identical DNA unless one has heart issues as the babies may share one placenta. Medically these types of twin pregnancies may be referred In this case, the sperm fertilises an egg that later splits into separate embryos. Normally, only fraternal twins have separate placentas. Answer (1 of 5): About a third of identicals will present with their own placentas. And rounding out the stats: 60%-70% of all identical The later the split occurs, the more cells will have accumulated when the twins separate. Identical twins that share a single placenta are called monochorionic twins (MC). These pregnancies are the rarest and only account for roughly 1%-5% of all twin pregnancies. To a standard DNA test, they are indistinguishable. Researchers say, semi-identical twins are more genetically alike than fraternal twins, but not genetically identical like identical twins. Very rare. While fraternal twins (2 eggs and 2 sperm) are always surrounded in their own sacs and have their own individual placentas, 70% of identical twins may end up sharing a single placenta. Fraternal (dizygotic) twins do run in families. Can doctors tell if twins are identical or fraternal? Monochorionic, diamniotic (MCDA) twins are the product of a single fertilized ovum (egg), resulting in genetically identical offspring. Fraternal twins are almost like two siblings. The incidence of spontaneous monozygotic twins is the same all over the world about 1 in 250 pregnancies, though it increases if the pregnancy was achieved with IVF in-vitro fertilization. When twins are born, the physician is usually able to identify whether twins are identical or fraternal by examining the placenta; identical twins generally share a placenta, while fraternal twins are usually in two separate placentas.
Inner amnion & outer corion. They come from the same fertilized egg and share the same genetic blueprint. Identical twins that share a single placenta are called monochorionic twins (MC). One placenta and two amniotic sacs. Identical twins are always the same sex, so if your twins are identical, you'll have 2 girls or 2 boys. Are twins genetic? Identical twins that share a single placenta are called monochorionic twins (MC). Most commonly, the egg will split around 4-5 days after fertilization. Identical twins are rare. Hi. Studies comparing the IQs of identical twins who were separated at birth have tended to conclude that a person's IQ is determined more by heredity than by environment. Twins who share the same amniotic sac, a condition that occurs in less than 1 percent of all U.S. twin pregnancies, face serious risks including cord entanglement, which can cut off the blood flow from the placenta to the fetus. In contrast, fraternal (dizygotic) twins result from the fertilization of two separate eggs with two A placenta.
These triplets are called fraternal triplets and have genetic similarities just like any siblings. Most identical twins have a single placenta. Although this condition is rare, it is not unheard of. Each twin has a separate amniotic sac, the fluid-filled sac that protects a fetus in the womb. Because they come from the same zygote, they will have the same chromosomes and be the same sex. Giving birth to identical twins is not hereditary, so the rate of it happening is relatively constant all over the world. In this scenario, the identical twins have time to form separate sacs but will end up sharing a placenta. What are monochorionic, diamniotic twins? While fraternal twins (2 eggs and 2 sperm) are always surrounded in their own sacs and have their own individual placentas, 70% of identical twins may end up sharing a single placenta. The medical term for these twins is dichorionic diamniotic or DCDA twins. The zygote splits into two parts after conception, (MCMA) twins; There is only one shared placenta and no amniotic membrane between the twins. What that means is that the two embryos that form have their own placenta and amniotic sac. Monochorionic-Diamniotic (Mono/Di or Mo/Di) Identical Twins. [14] Identical twins are much more rare than fraternal twins. In rare cases, they share both the placenta This is true of all non-identical twins, and about a third of identical twins. Scans later in pregnancy, when your babies' genitals have developed, may show your babies' sex.
While fraternal twins (2 eggs and 2 sperm) are always surrounded in their own sacs and have their own individual placentas, 70% of identical twins may end up sharing a single placenta. It is terrifying, but we were told it only happens in 15% of all identical twins - very rare! A common but erroneous belief is that the two major twin types can be correctly identified at birth by looking at the placenta, the sac attached to the other end of each kids umbilical cord.
Only 1% of identical twins share both a single placenta and a However, identical twins are caused when the same egg splits into two embryos, and if this happens late enough, its possible for both twins to share the same placenta. While fraternal twins (2 eggs and 2 sperm) are always surrounded in their own sacs and have their own individual placentas, 70% of identical twins may end up sharing a single placenta. When you have one zygote that splits into two during early pregnancy and grows into separate embryos, youll have identical twins. Monozygotic twins form from a single (mono) fertilized egg (zygote). I talked I had mo/di twins and was diagnosed with TTTS at 21w2d. They share the same placenta as well. Non-identical twins occur when two separate eggs are each fertilized by a separate sperm. Only 1% of identical twins share both a single placenta and a The differences between identical and fraternal twins are due to how they are conceived. A boy has XY chromosomes and a girl has XX chromosomes. The occurrence of MCDA twins occurs at a rate of three to four in 1,000 live births. If the placenta has already formed when the embryo splits in two, one placenta will sustain both twins, who will each have an umbilical cord linking them to the shared placenta. What does "monozygotic" mean? Known as monozygotic twins, a single egg is fertilised then splits into two (or, very rarely, three or more) creating identical babies with the same genes, physical features and sex. Monochorionic twins are identical twins who share one placenta. What two sacs develop inside the womb? Identical twins share the same placenta and the same genes. Do identical twins have a shared or separate placenta? Why do identical twins still look different? Also known as monozygotic twins, the gender of the twins is usually the same, with a few exceptions. eggs fertilized by separate sperm; they generally share about half of their genes. Even though identical twins do not always share a single placenta, one shared placenta always indicates identical twins. Identical twinning is officially described as monozygotic. Identical twins may share the same placenta, or can have two placentas that are separate. These are the highest risk type of twin pregnancy and are also always identical. Do identical twins have placentas? Then two babies will result as Non-identical (dizygotic or fraternal) twins. The shared placenta contains abnormal blood vessels, which connect the umbilical cords and circulations of the twins. pregnant with Identical twins and they share one placenta she is terrified of Two eggs & two sperm. They typically do not share a placenta and can be fraternal or identical. Identical twins may either have their own separate placentas or they may share a common placenta. Monochorionic-Diamniotic (Mono/Di or Mo/Di) Identical Twins.
18 Why are monozygotic twins genetically identical whereas dizygotic twins share only 50%? Identical twins may or may not share one amniotic sac. And about 1% of identical twins have a single placenta and a single sack. Identical twins, or monozygotic twins, form when one fertilized egg splits in two and grows into two separate embryos. In a situation where a cow has two cycles some months apart, and it conceives during each cycle, it may birth the two calves months apart. In such cases, your baby will not have a separate amniotic sac or placenta. Most identical twins have a single placenta. Identical twins that share a placenta have some specific risks that need to be watched for. In this way, can fraternal twins be identical? One placenta and two amniotic sacs. 19 What percentage of genes do siblings share? MCDA twins share a single placenta (blood supply) but have separate amniotic sacs. If you have fraternal twins, each baby will have its own placenta. 70% of identical twins share a placenta, and 15-20% of these pregnancies are affected by TTTS. Monochorionic, diamniotic twins. Twin transfusion syndrome is when one of the babies is taking all of the nutrients through the placenta, and the other baby is getting none. In this scenario, the identical twins have When identical twins share a placenta their umbilical cords can attach to the placenta in random locations. An MCDA pregnancy results from a separation of a single zygote at ~4-8 days (blastocyst) following formation. These fraternal twins are no more alike than any other siblings in a family with the same biological mother and father. I was shocked, and still am scared. So when one twin has many mutations that the other doesn't, it's possible that the TTTS affects identical twins (or higher multiple gestations), who share a common monochorionic placenta .
Monochorionic-diamniotic twins are identical twins who share a placenta but 1 The fetus begins developing fingerprint patterns in the early weeks of pregnancy. If twins have separate chorion, they will have two separate placentas. The twins may or may not look or act alike. But, the twins share a placenta, the organ that provides the oxygen- and nutrient-rich blood that a fetus needs to grow and survive. One problem that can arise is that the placenta has to work harder, as it is working for two babies.
About a third of identical twins have two placentas. twin pregnancy. There is no real explanation as to why eggs (zygotes) split. It is important to note that twins who share a placenta and sac (Mo Mo or Mono Mono twins) are in the highest risk category. If the identical twins share a placenta they are at a higher risk of having twin-to-twin transfusion syndrome. faithhopelove22. Twins are two offspring produced by the same pregnancy. Identical twins can have their own, or share both the outer sac (chorion) and the inner sac (amnion): 1 chorion, 2 amnions, 1 placenta (most common) roughly 65-70%. These are monochorionic diamniotic or MCDA twins. Di di twins are Monoamniotic twins are always monochorionic and are usually termed Monoamniotic-Monochorionic ("MoMo" or "Mono Mono") twins. Contradicting nearly all the medical textbooks, doctors have proven for the This is a risk due to a shared placenta. Meanwhile, fraternal twins result when two eggs are released by the mother (instead of just the "usual" one), which is In some cases, they have two placentas. Non-identical, also known as dizygotic twins, develop when two eggs are fertilized by two sperms. There are two types of twin situations where your babies can be in different sacs, separated by whether they share a placenta, (mono di) or have separate placenta (di di.) Twins are two offspring produced by the same pregnancy. Non-identical twins have separate placentas, amniotic sacs, and umbilical cords. share unequal amounts of the placenta's blood supply resulting in the two fetuses growing at different rates. This is only possible with identical twins. Non-identical twins. Twins can be either monozygotic ('identical'), meaning that they develop from one zygote, which splits and forms two embryos, or dizygotic ('non-identical' or 'fraternal'), meaning that each twin develops from a separate egg and each egg is fertilized by its own sperm cell. Fraternal twins have separate placentas and umbilical cords. If the zygote takes from four to eight days to divide, the twins share a common placenta (monochorionic) and the membrane that separates the fetal twins two amniotic sacs is thin (diamnionic). Twins are mainly monozygotic or dizygotic. Non-identical twins form from two completely separate eggs which are fertilised by two completely separate sperm. If the identical twins share a placenta they are at a higher risk of having twin-to-twin transfusion syndrome. They share the same genetic composition and placenta. Want to Know More? Identical twin/triplets may share a placenta or an amniotic sac or they may have separate placentas and sacs. They share the placenta, but have two separate umbilical cords.Monoamniotic twins develop when an embryo does If a fertilised egg splits only partially into two what happens? No, identical twins are genetically identical, so are always the same sex. Duh. If your first ultrasound scan is done before 14 weeks, it should be possible to tell accurately what kind of placenta your twins have. While fraternal twins (2 eggs and 2 sperm) are always surrounded in their own sacs and have their own individual placentas , 70% of identical twins may end up sharing a single placenta .
One Placenta. Non-identical twins are uniquely separate individuals who just happen to be gestating at the same time and place as each other. They came from the same egg and--depending on when "the split" happened--will determine whether or not they have the same sac or 2. Monozygotic multiples form from a single egg and sperm combination that I am 10 weeks pregnant with identical twins sharing the same placenta, but two sacs. Most commonly, the egg will split around 4-5 days after fertilization. These twins are formed independently. Non-identical twins form from two separate eggs which are fertilized by two completely separate sperm. They may or may not share a placenta. Can identical twins have separate sacs? 2 Identical twins are known scientifically as monozygotic twins.. Depending on when the split occurs will determine if the twins share a placenta, with either one or two chorions and amnions, or if prenatal environments Which of the following is TRUE regarding heredity It is impossible to say what percentage of an individual's personality or intelligence is inherited While fraternal twins (2 eggs and 2 sperm) are always surrounded in their own sacs and have their own individual placentas, 70% of identical twins may end up sharing a single placenta. Identical twins do not have identical fingerprints, even though their identical genes give them very similar patterns. In most cases, identical twins share one placenta, but have separate amniotic sacs. Doctors do not routinely test non placenta sharers for identical DNA unless one has heart issues as the babies may share one placenta. Medically these types of twin pregnancies may be referred In this case, the sperm fertilises an egg that later splits into separate embryos. Normally, only fraternal twins have separate placentas. Answer (1 of 5): About a third of identicals will present with their own placentas. And rounding out the stats: 60%-70% of all identical The later the split occurs, the more cells will have accumulated when the twins separate. Identical twins that share a single placenta are called monochorionic twins (MC). These pregnancies are the rarest and only account for roughly 1%-5% of all twin pregnancies. To a standard DNA test, they are indistinguishable. Researchers say, semi-identical twins are more genetically alike than fraternal twins, but not genetically identical like identical twins. Very rare. While fraternal twins (2 eggs and 2 sperm) are always surrounded in their own sacs and have their own individual placentas, 70% of identical twins may end up sharing a single placenta. Fraternal (dizygotic) twins do run in families. Can doctors tell if twins are identical or fraternal? Monochorionic, diamniotic (MCDA) twins are the product of a single fertilized ovum (egg), resulting in genetically identical offspring. Fraternal twins are almost like two siblings. The incidence of spontaneous monozygotic twins is the same all over the world about 1 in 250 pregnancies, though it increases if the pregnancy was achieved with IVF in-vitro fertilization. When twins are born, the physician is usually able to identify whether twins are identical or fraternal by examining the placenta; identical twins generally share a placenta, while fraternal twins are usually in two separate placentas.
Inner amnion & outer corion. They come from the same fertilized egg and share the same genetic blueprint. Identical twins that share a single placenta are called monochorionic twins (MC). One placenta and two amniotic sacs. Identical twins are always the same sex, so if your twins are identical, you'll have 2 girls or 2 boys. Are twins genetic? Identical twins that share a single placenta are called monochorionic twins (MC). Most commonly, the egg will split around 4-5 days after fertilization. Identical twins are rare. Hi. Studies comparing the IQs of identical twins who were separated at birth have tended to conclude that a person's IQ is determined more by heredity than by environment. Twins who share the same amniotic sac, a condition that occurs in less than 1 percent of all U.S. twin pregnancies, face serious risks including cord entanglement, which can cut off the blood flow from the placenta to the fetus. In contrast, fraternal (dizygotic) twins result from the fertilization of two separate eggs with two A placenta.
These triplets are called fraternal triplets and have genetic similarities just like any siblings. Most identical twins have a single placenta. Although this condition is rare, it is not unheard of. Each twin has a separate amniotic sac, the fluid-filled sac that protects a fetus in the womb. Because they come from the same zygote, they will have the same chromosomes and be the same sex. Giving birth to identical twins is not hereditary, so the rate of it happening is relatively constant all over the world. In this scenario, the identical twins have time to form separate sacs but will end up sharing a placenta. What are monochorionic, diamniotic twins? While fraternal twins (2 eggs and 2 sperm) are always surrounded in their own sacs and have their own individual placentas, 70% of identical twins may end up sharing a single placenta. The medical term for these twins is dichorionic diamniotic or DCDA twins. The zygote splits into two parts after conception, (MCMA) twins; There is only one shared placenta and no amniotic membrane between the twins. What that means is that the two embryos that form have their own placenta and amniotic sac. Monochorionic-Diamniotic (Mono/Di or Mo/Di) Identical Twins. [14] Identical twins are much more rare than fraternal twins. In rare cases, they share both the placenta This is true of all non-identical twins, and about a third of identical twins. Scans later in pregnancy, when your babies' genitals have developed, may show your babies' sex.
While fraternal twins (2 eggs and 2 sperm) are always surrounded in their own sacs and have their own individual placentas, 70% of identical twins may end up sharing a single placenta. It is terrifying, but we were told it only happens in 15% of all identical twins - very rare! A common but erroneous belief is that the two major twin types can be correctly identified at birth by looking at the placenta, the sac attached to the other end of each kids umbilical cord.
Only 1% of identical twins share both a single placenta and a However, identical twins are caused when the same egg splits into two embryos, and if this happens late enough, its possible for both twins to share the same placenta. While fraternal twins (2 eggs and 2 sperm) are always surrounded in their own sacs and have their own individual placentas, 70% of identical twins may end up sharing a single placenta. When you have one zygote that splits into two during early pregnancy and grows into separate embryos, youll have identical twins. Monozygotic twins form from a single (mono) fertilized egg (zygote). I talked I had mo/di twins and was diagnosed with TTTS at 21w2d. They share the same placenta as well. Non-identical twins occur when two separate eggs are each fertilized by a separate sperm. Only 1% of identical twins share both a single placenta and a The differences between identical and fraternal twins are due to how they are conceived. A boy has XY chromosomes and a girl has XX chromosomes. The occurrence of MCDA twins occurs at a rate of three to four in 1,000 live births. If the placenta has already formed when the embryo splits in two, one placenta will sustain both twins, who will each have an umbilical cord linking them to the shared placenta. What does "monozygotic" mean? Known as monozygotic twins, a single egg is fertilised then splits into two (or, very rarely, three or more) creating identical babies with the same genes, physical features and sex. Monochorionic twins are identical twins who share one placenta. What two sacs develop inside the womb? Identical twins share the same placenta and the same genes. Do identical twins have a shared or separate placenta? Why do identical twins still look different? Also known as monozygotic twins, the gender of the twins is usually the same, with a few exceptions. eggs fertilized by separate sperm; they generally share about half of their genes. Even though identical twins do not always share a single placenta, one shared placenta always indicates identical twins. Identical twinning is officially described as monozygotic. Identical twins may share the same placenta, or can have two placentas that are separate. These are the highest risk type of twin pregnancy and are also always identical. Do identical twins have placentas? Then two babies will result as Non-identical (dizygotic or fraternal) twins. The shared placenta contains abnormal blood vessels, which connect the umbilical cords and circulations of the twins. pregnant with Identical twins and they share one placenta she is terrified of Two eggs & two sperm. They typically do not share a placenta and can be fraternal or identical. Identical twins may either have their own separate placentas or they may share a common placenta. Monochorionic-Diamniotic (Mono/Di or Mo/Di) Identical Twins.
18 Why are monozygotic twins genetically identical whereas dizygotic twins share only 50%? Identical twins may or may not share one amniotic sac. And about 1% of identical twins have a single placenta and a single sack. Identical twins, or monozygotic twins, form when one fertilized egg splits in two and grows into two separate embryos. In a situation where a cow has two cycles some months apart, and it conceives during each cycle, it may birth the two calves months apart. In such cases, your baby will not have a separate amniotic sac or placenta. Most identical twins have a single placenta. Identical twins that share a placenta have some specific risks that need to be watched for. In this way, can fraternal twins be identical? One placenta and two amniotic sacs. 19 What percentage of genes do siblings share? MCDA twins share a single placenta (blood supply) but have separate amniotic sacs. If you have fraternal twins, each baby will have its own placenta. 70% of identical twins share a placenta, and 15-20% of these pregnancies are affected by TTTS. Monochorionic, diamniotic twins. Twin transfusion syndrome is when one of the babies is taking all of the nutrients through the placenta, and the other baby is getting none. In this scenario, the identical twins have When identical twins share a placenta their umbilical cords can attach to the placenta in random locations. An MCDA pregnancy results from a separation of a single zygote at ~4-8 days (blastocyst) following formation. These fraternal twins are no more alike than any other siblings in a family with the same biological mother and father. I was shocked, and still am scared. So when one twin has many mutations that the other doesn't, it's possible that the TTTS affects identical twins (or higher multiple gestations), who share a common monochorionic placenta .
Monochorionic-diamniotic twins are identical twins who share a placenta but 1 The fetus begins developing fingerprint patterns in the early weeks of pregnancy. If twins have separate chorion, they will have two separate placentas. The twins may or may not look or act alike. But, the twins share a placenta, the organ that provides the oxygen- and nutrient-rich blood that a fetus needs to grow and survive. One problem that can arise is that the placenta has to work harder, as it is working for two babies.