What is Triploidy?
Triploidy is a rare chromosomal abnormality. Typical cells have 46 chromosomes, with 23 inherited from the mother and 23 inherited from the father. Triploidy is the presence of an additional set of chromosomes in the cell for a total of 69 chromosomes rather than the normal 46 chromosomes per cell.
The extra set of chromosomes originates either from the father or the mother during fertilization. Infants with triploidy usually are miscarried early in the pregnancy. If the pregnancy continues to term, the infant dies within the first days of life. A few affected individuals have been reported to have survived to adulthood, but suffered from developmental delay, learning difficulties, seizures, hearing loss and other abnormalities.
Those that survive have mosaic triploidy, meaning that some cells have the normal number of 46 chromosomes and other cells have 69 chromosomes per cell. Infants affected with complete triploidy suffer from growth restriction and multiple birth defects.
How common is Triploidy?
Triploidy is uncommon. It accounts for 1-3 percent of all pregnancies. The condition occurs slightly more often in males than females; it is estimated that 2/3 of triploid pregnancies are male. Please discuss with your doctor for further information.
What are the symptoms of Triploidy?
Pregnant women carrying fetuses with triploid syndrome may have preeclampsia. Symptoms of this condition include:
- Albuminuria, or high levels of the protein albumin in the urine
- Edema, or swelling
Triploidy’s physical effects in a fetus depend on whether the extra chromosomes came from the father or the mother. Paternally inherited chromosomes can cause small heads and an enlarged, cyst-filled placenta. Maternally inherited chromosomes can cause severe growth problems, an enlarged head, and a small placenta without cysts.
Infants with triploidy who reach the full-term stage often have one or more birth defects after delivery, including:
- A cleft lip and cleft palate
- Heart defects
- Limb abnormalities, such as toe and finger webbing
- Kidney defects, such as a cystic kidney
- Neural tube defects, such as spina bifida
- Wide-set eyes
There may be some symptoms not listed above. If you have any concerns about a symptom, please consult your doctor.
When should I see my doctor?
If you or your loved one has any signs or symptoms listed above or you have any questions, please consult with your doctor. Everyone’s body acts differently. It is always best to discuss with your doctor what is best for your situation.
What causes Triploidy?
Triploidy is the result of an extra set of chromosomes. This can occur when two sperm fertilizing one normal egg or a diploid sperm (sperm with two set of chromosomes) fertilizes a normal egg. It can also occur when a normal sperm fertilizes an egg that has an extra set of chromosomes.
Two different kinds of abnormal fertilization can cause triploidy:
- Digynic fertilization, in which the mother provides the extra set of chromosomes. This usually occurs when the mother has a diploid ovum, or egg cell, that’s fertilized by a single sperm.
- Diandric fertilization, in which the father provides the extra set of chromosomes. This usually occurs when one of the father’s diploid sperm (or two sperm at one time, in a process known as dispermy) fertilize the ovum.
Digynic pregnancies are more likely to end when the baby is closer to full-term. Diandric pregnancies are more likely to result in spontaneous miscarriages early on.
A partial molar pregnancy (or hydatidiform mole) can cause triploidy and is a nonviable pregnancy. It can also cause many complications, including cancer and an increased risk of another molar pregnancy.
What increases my risk for Triploidy?
There aren’t any risk factors. It’s not more common in older mothers like other chromosome abnormalities, such as Down syndrome. Couples who experience one pregnancy with triploidy aren’t at higher risk for it in future pregnancies. Triploidy is also not hereditary.
Please consult with your doctor for further information.
Diagnosis & treatment
The information provided is not a substitute for any medical advice. ALWAYS consult with your doctor for more information.
How is Triploidy diagnosed?
A chromosome analysis (karyotype) test is the only test that can confirm a triploidy diagnosis. This test counts the number of chromosomes in a fetus’s genes to determine the existence of extra chromosomes.
To perform this test, a doctor needs a tissue sample from the fetus. Because the fetus and placenta come from the same fertilized egg, a doctor can use a placenta sample for testing.
An amniocentesis can also be used to diagnose triploidy. The doctor extracts amniotic fluid and then analyzes the sample for signs of abnormal chromosomes.
Triploidy may be suspected prenatally, or before the baby is born, if a maternal serum screening test is ordered and has certain abnormalities. This blood test, typically performed during the second trimester of pregnancy, is not designed to detect the condition. However, unusual test results such as too much or too little of certain proteins in the blood, can alert an obstetrician to potential problems. More tests may be needed if a serum screening test has abnormal results.
Triploidy can also be suspected during an ultrasound, which is commonly performed during pregnancy to examine the fetus. This test can help the doctor see if a fetus has certain anatomic abnormalities.
How is Triploidy treated?
Triploidy cannot be treated or cured. Pregnancies that last until the baby is delivered are rare. If an infant does survive, the baby usually receives palliative care. Medicinal and surgical treatments are not used because of the ultimately lethal nature of the condition.
If doctors discover triploidy while a woman is pregnant, she can terminate the pregnancy or carry it to term or until a spontaneous miscarriage occurs. If she chooses to carry the baby to term, she should be monitored closely for complications caused by triploidy, including:
- Preeclampsia, which can be life-threatening
- Choriocarcinoma, a type of cancer rarely caused by tissue left over from a partial molar pregnancy
Lifestyle changes & home remedies
What are some lifestyle changes or home remedies that can help me manage Triploidy?
The following lifestyles and home remedies might help you cope with Triploidy:
- Losing your baby to triploidy can be difficult, but you don’t have to confront these feelings alone. Seek out support groups, online forums, or discussion groups to talk about your experiences. Thousands of other women have also had to face a situation similar to yours and have sought out help and support in these groups.
- Carrying a baby with triploidy doesn’t increase your chances of another similar pregnancy, so it’s safe to conceive another child without having to worry about a higher risk of another baby with triploidy. If you do decide to have another child, continue to seek prenatal care and testing to make sure that your baby receives the best care possible.
If you have any questions, please consult with your doctor to better understand the best solution for you.
Hello Health Group does not provide medical advice, diagnosis or treatment.
Review Date: February 27, 2018 | Last Modified: December 8, 2019