Amelia may be present as an isolated defect, but it is often associated with major malformations in other organ systems. These frequently include cleft lip and/or palate, body wall defects, malformed head, and defects of the neural tube, kidneys, and diaphragm. Facial clefts may be accompanied by other facial anomalies such as abnormally small jaw, and missing ears or nose. The body wall defects allow internal organs to protrude through the abdomen. Head malformations may be minor to severe with a near absence of the brain. The diaphragm may be herniated or absent and one or both kidneys may be small or absent.

Several terms are used to describe congenital abnormalities. (Some of these are also used to describe noncongenital conditions, and more than one term may apply in an individual condition.)

A limb anomaly is called a dysmelia. These include all forms of limbs anomalies, such as amelia, ectrodactyly, phocomelia, polymelia, polydactyly, syndactyly, polysyndactyly, oligodactyly, brachydactyly, achondroplasia, congenital aplasia or hypoplasia, amniotic band syndrome, and cleidocranial dysostosis.

Congenital anomalies of the heart include patent ductus arteriosus, atrial septal defect, ventricular septal defect, and tetralogy of fallot.

Congenital anomalies of the nervous system include neural tube defects such as spina bifida, meningocele, meningomyelocele, encephalocele and anencephaly. Other congenital anomalies of the nervous system include the Arnold-Chiari malformation, the Dandy-Walker malformation, hydrocephalus, microencephaly, megalencephaly, lissencephaly, polymicrogyria, holoprosencephaly, and agenesis of the corpus callosum.

Congenital anomalies of the gastrointestinal system include numerous forms of stenosis and atresia, and perforation, such as gastroschisis.

Congenital anomalies of the kidney and urinary tract (CAKUT) include renal parenchyma, kidneys, and urinary collecting system.

Defects can be bilateral or unilateral, and different defects often coexist in an individual child

The complete absence of an arm or leg in amelia occurs as a result of the limb formation process being either prevented or interrupted very early in the developing embryo: between 24 and 36 days following fertilization. Tetra-amelia syndrome appears to have an autosomal recessive pattern of inheritance - that is, the parents of an individual with tetra-amelia syndrome each carry one copy of the mutated gene, but do not show signs and symptoms of the condition. In a few cases, amelia may be attributed to health complications during the early stages of pregnancy, including infection, failed abortion or complications associated with removal of an IUD after pregnancy, or use of teratogenic drugs, such as thalidomide.

Ectromelia is a congenital condition where long bones are missing or underdeveloped.

Examples include:

- Amelia

- Hemimelia

- Phocomelia

- Sirenomelia

Tetra-amelia syndrome is characterized by the complete absence of all four limbs. The syndrome causes severe malformations of various parts of the body, including the face and head, heart, nervous system, skeleton, and genitalia. In many cases, the lungs are underdeveloped, which makes breathing difficult or impossible. Because children with tetra-amelia syndrome have such serious medical problems, most are stillborn or die shortly after birth.

The following is a list of symptoms that have been associated with Roberts syndrome:

- Bilateral Symmetric Tetraphocomelia- a birth defect in which the hands and feet are attached to shortened arms and legs

- Prenatal Growth Retardation

- Hypomelia (Hypoplasia)- the incomplete development of a tissue or organ; less drastic than aplasia, which is no development at all

- Oligodactyly- fewer than normal number of fingers or toes

- Thumb Aplasia- the absence of a thumb

- Syndactyly- condition in which two or more fingers (or toes) are joined together; the joining can involve the bones or just the skin between the fingers

- Clinodactyly- curving of the fifth finger (little finger) towards the fourth finger (ring finger) due to the underdevelopment of the middle bone in the fifth finger

- Elbow/Knee Flexion Contractures- an inability to fully straighten the arm or leg

- Cleft Lip- the presence of one or two vertical fissures in the upper lip; can be on one side (unilateral) or on both sides (bilateral)

- Cleft Palate- opening in the roof of the mouth

- Premaxillary Protrusion- upper part of the mouth sticks out farther than the lower part of the mouth

- Micrognathia- small chin

- Microbrachycephaly- smaller than normal head size

- Malar Hypoplasia- underdevelopment of the cheek bones

- Downslanting Palpebral Fissures- the outer corners of the eyes point downwards

- Ocular Hypertelorism- unusually wide-set eyes

- Exophthalmos- a protruding eyeball

- Corneal Clouding- clouding of the front-most part of the eye

- Hypoplastic Nasal Alae- narrowing of the nostrils that can decrease the width of the nasal base

- Beaked Nose- a nose with a prominent bridge that gives it the appearance of being curved

- Ear Malformations

- Intellectual disability

- Encephalocele (only in severe cases)- rare defect of the neural tube characterized by sac-like protrusions of the brain

Mortality is high among those severely affected by Roberts syndrome; however, mildly affected individuals may survive to adulthood

Tetra-amelia syndrome ("" + "amelia"), also called autosomal recessive tetraamelia, is an extremely rare autosomal recessive congenital disorder characterized by the absence of all four limbs. Other areas of the body are also affected by malformations, such as the face, skull, reproductive organs, anus and pelvis. The disorder is caused by mutations in the WNT3 gene.

Congenital amputation is birth without a limb or limbs, or without a part of a limb or limbs.

It is known to be caused by blood clots forming in the fetus while "in utero" (vascular insult) and from amniotic band syndrome: fibrous bands of the amnion that constrict foetal limbs to such an extent that they fail to form or actually fall off due to missing blood supply. Congenital amputation can also occur due to maternal exposure to teratogens during pregnancy.

Little is known about the natural history of Roberts syndrome due to its wide clinical variability. The prognosis of the disease depends on the malformations, as the severity of the malformations correlates with survival. The cause of death for most fatalities of Roberts syndrome have not been reported; however, five deaths were reportedly due to infection.

The following are observations that have been made in individuals with cytogenetic findings of PCS/HR or ESCO2 mutations:

- The symptom of prenatal growth retardation is the most common finding and can be moderate to severe. Postnatal growth retardation can also be moderate to severe and correlates with the degree of severity of limb and craniofacial malformations.

- In limb malformations, the upper limbs are typically more severely affected than the lower limbs. There have been many cases of only upper limb malformation.

- In hand malformations, the thumb is most often affected, followed by the fifth finger (the little finger). In severe cases, the patient may only have three fingers and in rare cases only one.

- In craniofacial malformations, mildly affected individuals will have no abnormalities of the palate. The most severely affected will have a fronto-ethmoid-nasal-maxillary encephalocele.

- The severity of limb malformations and craniofacial malformations is correlated.

- Other abnormalities can occur in different parts of the body, including:

- Heart- atrial septal defects, ventricular septal defects, patent ductus arteriosus

- Kidneys- polycystic kidney, horseshoe kidney

- Male Genitals- enlarged penis, cryptorchidism

- Female Genitals- enlarged clitoris

- Hair- sparse, silvery-blonde scalp hair

- Cranial Nerve Paralysis, Moyamoya disease, Stroke, Intellectual disability

Dysmelia (from Gr. δυσ- "dys", "bad" + μέλ|ος "mél|os", "limb" + Eng. suff. -ia) is a congenital disorder of a limb resulting from a disturbance in embryonic development.

Dysmelia can refer to

- missing (aplasia) limbs: amelia, oligodactyly, congenital amputation e.g. Tibial or Radial aplasia

- malformation of limbs: shortening (micromelia, rhizomelia or mesomelia), ectrodactyly, phocomelia, meromelia, syndactyly, brachydactyly, club foot

- too many limbs: polymelia, polydactyly, polysyndactyly

- others: Tetraamelia, hemimelia, Symbrachydactyly

Yim–Ebbin syndrome is a congenital disorder characterized by the absence of arms, a cleft lip and palate, hydrocephalus, and an iris coloboma. It was first described by Yim and Ebbin in 1982, and later by Thomas and Donnai in 1994. In 1996, a third case was reported by Froster et al. who suggested that the three cases were related and represented a distinct syndrome. In 2000, a similar case was reported by Pierri et al.

It is also known as "amelia cleft lip palate hydrocephalus iris coloboma".

Symptoms vary from one type of the syndrome to another and from one patient to another, but they include:

- Very pale or brilliantly blue eyes, eyes of two different colors (complete heterochromia), or eyes with one iris having two different colors (sectoral heterochromia)

- A forelock of white hair ("poliosis"), or premature graying of the hair

- Appearance of wide-set eyes due to a prominent, broad nasal root ("dystopia canthorum")—particularly associated with Type I) also known as "telecanthus"

- Moderate to profound hearing loss (higher frequency associated with Type II);

- A low hairline and eyebrows that meet in the middle ("synophrys")

- Patches of white skin pigmentation, in some cases

- Abnormalities of the arms, associated with Type III

- neurologic manifestations, associated with Type IV

- Cleft lip, mostly associated with Type I

Waardenburg syndrome has also been associated with a variety of other congenital disorders, such as intestinal and spinal defects, elevation of the scapula and cleft lip and palate. Sometimes this is concurrent with Hirschsprung disease.

The exact cause of congenital amputation is unknown and can result from a number of causes. However, most cases show that the first three months in a pregnancy are when most birth defects occur because that is when the organs of the fetus are beginning to form. One common cause is amniotic band syndrome, which occurs when the inner fetal membrane (amnion) ruptures without injury to the outer membrane (chorion). Fibrous bands from the ruptured amnion float in the amniotic fluid and can get entangled with the fetus, thus reducing blood supply to the developing limbs to such an extent that the limbs can become strangulated; the tissues die and are absorbed into the amniotic fluid. A baby with congenital amputation can be missing a portion of a limb or the entire limb, which results in the complete absence of a limb beyond a certain point where only a stump is left is known as transverse deficiency or amelia. When a specific part is missing, it is referred to as longitudinal deficiency. Finally, phocomelia occurs when only a mid-portion of a limb is missing; for example when the hands or feet are directly attached to the trunk of the body.

Amnion ruptures can be caused by:

- teratogenic drugs (e.g. thalidomide, which causes phocomelia), or environmental chemicals

- ionizing radiation (atomic weapons, radioiodine, radiation therapy)

- infections

- metabolic imbalance

- trauma

Congenital amputation is the least common reason for amputation, but it is projected that one in 2000 babies are born each year with a missing or deformed limb. During certain periods in history, an increase in congenital amputations has been documented. One example includes the thalidomide tragedy that occurred in the 1960s when pregnant mothers were given a tranquilizer that contained the harmful drug, which produced an increase in children born without limbs. Another example was the 1986 Chernobyl catastrophe in Ukraine, where the radiation exposure caused many children to be born with abnormal or missing limbs .

Waardenburg syndrome is a rare genetic disorder most often characterized by varying degrees of deafness, minor defects in structures arising from the neural crest, and pigmentation changes. It was first described in 1951. The syndrome was later found to have four types. For example, type II was identified in 1971, to describe cases where dystopia canthorum was not present. Some types are now split into subtypes, based upon the gene responsible for the condition.

A breech birth occurs when a baby is born bottom first instead of head first. Around 3-5% of pregnant women at term (37–40 weeks pregnant) will have a breech baby.

Most babies in the breech position are born by a caesarean section because it is seen as safer than being born vaginally.

As most breech babies are delivered by caesarean section in developed countries, doctors and midwives may lose the skills required to safely assist women giving birth to a breech baby vaginally. Delivering all breech babies by caesarean section in developing countries may be very difficult to implement or even impossible as there are not always resources available to provide this service.

Types of breech depend on how the baby’s legs are lying.

- A frank breech (otherwise known as an extended breech) is where the baby’s legs are up next to its abdomen, with its knees straight and its feet next to its ears. This is the most common type of breech.

- A complete breech (flexed) breech is when the baby appears as though it is sitting crossed-legged with its legs bent at the hips and knees.

- A footling breech is when one or both of the baby’s feet are born first instead of the pelvis. This is more common in babies born prematurely or before their due date.

In addition to the above, breech births in which the sacrum is the fetal denominator can be classified by the position of a fetus. Thus sacro-anterior, sacro-transverse and sacro-posterior positions all exist, but left sacro-anterior is the most common presentation. Sacro-anterior indicates an easier delivery compared to other forms.

Affected individuals typically develop symptoms including high fevers, shaking, chills, fatigue, headaches, vomiting, and general illness within 48 hours of the initial infection. The erythematous skin lesion enlarges rapidly and has a sharply demarcated, raised edge. It appears as a red, swollen, warm, and painful rash, similar in consistency to an orange peel. More severe infections can result in vesicles (pox or insect bite-like marks), blisters, and petechiae (small purple or red spots), with possible skin necrosis (death). Lymph nodes may be swollen, and lymphedema may occur. Occasionally, a red streak extending to the lymph node can be seen.

The infection may occur on any part of the skin, including the face, arms, fingers, legs, and toes; it tends to favour the extremities. Fat tissue and facial areas, typically around the eyes, ears, and cheeks, are most susceptible to infection. Repeated infection of the extremities can lead to chronic swelling (lymphangitis).

Erysipelas is an acute infection typically with a skin rash, usually on any of the legs and toes, face, arms, and fingers. It is an infection of the upper dermis and superficial lymphatics, usually caused by beta-hemolytic group A "Streptococcus" bacteria on scratches or otherwise infected areas. Erysipelas is more superficial than cellulitis, and is typically more raised and demarcated. The term is from Greek ἐρυσίπελας, meaning "red skin".