- Fetal hydantoin syndrome is combination of defects caused to developing fetus when it is exposed to phenytoin– an anticonvulsant drug. It is also known as fetal dilantin syndrome, congenital hydantoin syndrome, dilantin embryopathy or phenytoin embryopathy.
- Phenytoin is commonly prescribed for epilepsy. Dilantin is one of popular brand of phenytoin.
Cause of fetal hydantoin syndrome
- When phenytoin is used in pregnancy to control epilepsy, it crosses placenta in such a way that developing fetus receives much higher dose of medication than the mother is taking (the drug is metabolized differently by fetus). The specific amount of phenytoin ingestion required to produce this syndrome is not determined.
- Not all infants exposed to phenytoin will suffer from this syndrome. In about 5-10 % of cases, the chance of developing this syndrome exist. It may be due to combination of genetic and environmental factors.
- Its incidence in both male and female child is equal.
- It is unclear till today whether this syndrome is caused by phenytoin itself or its metabolites.
Signs and symptoms of fetal hydantoin syndrome
- Symptoms may vary from one child to another. Symptoms may not be noticeable at birth but will become apparent as affected child grows older.
- Babies with this syndrome may born with following health problems:
- Limb defects including hypoplastic nails and distal phalanges.
- Skull and facial abnormalities like small head, cleft palate, short nose, wide distance between two eyes than normal, flat broad bridge of nose.
- Growth deficiency and development delay.
- Mental retardation.
- Heart defects including patent ductus arteriosus, ventricular septal defect and atrial septal defect.
Diagnosis
- There is no specific diagnostic test to identify fetal hydantoin syndrome.
- Diagnosis is made based on identification of symptoms in affected infants with history of phenytoin exposure during pregnancy.
Prevention
- If a woman who is on anti-convulsant therapy specially phenytoin wants to be pregnant, it is recommended to consult with her doctor to discuss about benefits and risk of taking those medicines during pregnancy.
- The best preventive measure is to avoid phenytoin during childbearing age.
- Woman should be treated with single anti-convulsant before conception and throughout pregnancy.
- If there is compulsion to take any anti-convulsant drug during pregnancy, folic acid supplementation before and after conception till delivery should be continued.
Treatment
- Treatment may differ from one child to another and is directed towards specific symptoms present in individual. An integrated team of pediatrician, neurologist, psychologist, surgeon and other professional may need to work together.
- The treatment may include occupational therapy, physical therapy and speech therapy. Various methods of behavioral and rehabilitative therapy may be useful. Psychosocial support from entire family is required.
- Some symptoms like cleft lip should be treated surgically. The first corrective surgery is done when the child is infant, and second corrective surgery is done when the child gets older and is related to cosmetic purpose only. Cleft palate may be surgically repaired or covered by an artificial device (prosthetics).
References
- Singh R, Kumar N, arora S, Bhandari R, Jain A. Fetal Hydantoin Syndrome and Its Anaesthetic Implications: A Case Report. Case Rep Anesthesiol. 2012; 2012: 370412.
- https://healthjade.net/fetal-hydantoin-syndrome/
- https://www.hxbenefit.com/fetal-hydantoin-syndrome.html
- https://www.epainassist.com/children/fetal-hydantoin-syndrome