What is High Risk Pregnancy?
A High Risk Pregnancy is one that puts the mother and/or fetus at a greater risk for complications during or after the pregnancy and/or birth. There are a number of conditions and risk factors, each with their own treatment, that can make a pregnancy high risk.
If you are pregnant, call your doctor if you experience any of the following symptoms:
- Heavy bleeding or any bleeding for more than twenty-four hours
- Blurred vision
- Rapid weight gain in legs or in face
- Severe headaches, fever, or chills
General Risk Factors for High Risk Pregnancy:
If you have experienced a previous high risk pregnancy, you have an increased chance of experiencing high-risk pregnancies later. Pre-existing conditions, including diabetes or HIV, also increase the risk of high risk pregnancy.
There are a variety of screenings and tests that pregnant women may undergo during prenatal care appointments to identify any issues that may come up in a pregnancy. If the results are unusual and indicative of a problem in the pregnancy, the pregnancy may be classified as high risk and additional prenatal care and testing may be warranted.
These screenings and tests start with a physical exam and blood pressure check. Your doctor may then administer an ultrasound and/or non-stress test, a urine test, and/or a blood glucose screening, as well as blood tests of both the mother and the fetus. Additional tests can include: a Group B Strep test; Chorionic Villus Sampling (CVS), which identifies chromosomal abnormalities usually between weeks 10-12 by testing cells found in the placenta; Electronic Fetal Heart Monitoring; and/or a Triple or Quadruple Screen, a blood test to measure levels of AFP, hCG, estrogen, and Inhibin A (the results are used to estimate the likelihood that the fetus has an abnormality). Additionally, your physician may perform an Amniocentesis (which tests fluids inside the amniotic sac), usually to check results of Triple or Quadruple Screen.
If a pregnancy is identified as high risk, additional prenatal care may be ordered by the obstetrician. The mother may need more frequent appointments to monitor the pregnancy, as well as additional ultrasounds. Fetal movement counting may be advised. Additional care may also include dietary changes, genetic counseling, medications, bed rest, hospitalization, or even induction of labor.
Pregnancy-Induced Conditions That May Cause a High-Risk Pregnancy:
Gestational Diabetes Mellitus (also known as gestational diabetes) is a pregnancy-induced condition in which a non-diabetic woman develops diabetes during her pregnancy. Gestational diabetes is routinely screened between 24-28 weeks gestation.
Preeclampsia is a syndrome that includes elevated blood pressure, increased urinary protein and changes in liver enzymes in a pregnant woman. Left untreated, the condition can cause long term health problems including fatality for the mother and/or baby.
Multiple Gestations - Twin, triplet and quadruplet pregnancies are considered to be high-risk pregnancies, as they often experience complications, such as preterm labor, preeclampsia, gestational diabetes, twin-to-twin transfusion syndrome, and tangled umbilical cords.
Placenta Previa occurs when the placenta attaches to the uterine wall so close to the cervix that it partially or completely covers the cervix. This can result in additional bleeding during pregnancy, hemorrhage during labor, and/or complications for the baby if the placenta detaches from the uterus prior to birth.
Cervical Incompetence - premature shortening and dilation of the cervix that is not caused by labor but by structural weakness in the cervix itself. This can be caused by previous cervical injury, surgery, DES (Diethylstilbestrol, or synthetic estrogen) exposure or inherited physical conditions.
Repeated Pregnancy Losses - 10-15% of all known pregnancies end in miscarriage (pregnancy loss before twenty weeks). When pregnancy loss occurs two or more times in a row, it is called Repeated Miscarriage. There are many causes for miscarriage; most have no known cause, but sometimes there are causes that may be treated.
Antiphospholipid Antibody Syndrome (APS) is an autoimmune blood clotting disorder that may cause problems such as recurrent miscarriage, preeclampsia, poor placental function, embolism or stillbirth.
Infections That Can Cause High-Risk Pregnancy:
HIV/AIDS - HIV positive women run the risk of passing the HIV virus to their unborn baby during pregnancy, birth or while breastfeeding. There are, however, effective ways to prevent the transmission of HIV/AIDS to from mother to infant.
CMV (Cytomegalovirus) is the most common type of congenital viral infection and occurs when a mother passes CMV to her unborn baby.
Rubella - unborn babies exposed to rubella through their mother's bloodstream are at risk for congenital rubella syndrome.
Chicken Pox - a fetus of a woman previously unexposed to chicken pox is at risk for birth defects and the mother is at greater risk for developing complications.
Congenital Conditions That May Cause a High Risk Pregnancy:
Congenital Defects are defined as abnormalities of structure, function or body mechanism that are present at birth. These deformities lead to mental or physical disabilities and may be fatal. There are over four thousand different birth defects.
- Congenital Heart Defects can be identified via echocardiography and help prepare doctors for any issues at birth.
- Neural Tube Defects - any problem in which the fetal neural tube was malformed and failed to close properly. NTDs can occur up and down the spine, from the forehead to the tail of the spine. A neural tube defect involving the skull is called an encephalocele. A NTD along the spinal column spine is called spina bifida. If the neural tube defect occurred while the brain was forming, failing to properly form a skull, it is called anencephaly.
Genetic Disorders That Cause A High-Risk Pregnancy:
Genetic Disorders such as extra or missing chromosomes (or chromosomal fragments) can be detected via karyotyping - a process in which the 46 chromosomes of the fetus (23 from Mom, 23 from Dad) are analyzed. Genetic problems can happen for a number of reasons.
Gene Deletions, Translocations, and Inversions: a mutation in which part of a chromosome or DNA sequence is missing or abnormally shaped. Any amount of material can be deleted, from a single base pair to an entire piece of chromosome.
Translocation - a chromosomal abnormality caused by the rearrangement of parts between two nonhomologous chromosomes. Translocation may be inherited from a parent or arise spontaneously and may not cause any developmental problems in children who have them. As adults, those with chromosomal translocations may be at higher risk for infertility and miscarriage.
Chromosomal Inversions - a chromosomal rearrangement in which a segment of chromosome breaks and rearranges within itself, reversed, end to end.
Trisomy Disorders - three copies of a particular chromosome exist rather than the normal two. Down Syndrome (Trisomy 21), Trisomy 13, and Edward Syndrome (Trisomy 18) are examples of trisomy disorders.
Monosomy Disorders - another form of chromosomal error in which one member of a pair of chromosomes are missing. There are too few chromosomes rather than too many. The only non-fatal monosomy is Turner Syndrome. The rest are incompatible with life.
Microdeletion - the missing part of a chromosome is so small that it affects a single gene or only a few genes.
Partial Monosomy exists when a portion of the chromosome is deleted, but the rest has two copies.
- Turner Syndrome - women missing all or part of an X chromosome. It is the only non-fatal full monosomy.
- Cri du Chat syndrome partial deletion on the arm of Chromosome 5, named for the cat-like cry of newborns with this condition.
- 1p36 Deletion Syndrome - partial monosomy caused by the deletion at the end of the short p arm chromosome.
- Wolf-Hirschhorn Syndrome (also known as chromosome deletion 4p syndrome due to the partial deletion on the short arm of chromosome 4).
Disorders of the Sex Chromosomes - Certain disorders are caused by genetic abnormalities of the sex chromosomes. For a child to be biologically male, he must have XY chromosomes. For a child to be genetically female, she must have two XX chromosomes.
- Turner Syndrome occurs when a woman inherits only one X chromosome.
- Kleinfelter Syndrome occurs when boys are born with XXY or XXXY sex chromosomes.
Some genetic problems are X-Linked, meaning they are carried by the X Chromosome. Females may be carriers these diseases, but because they have another X chromosome, the abnormal X chromosome may be canceled out. Males only have one X chromosomes and are generally the ones afflicted with the disease.
- Fragile X causes mental retardation in boys.
- Hemophilia A is another X-Linked Recessive disorder which impairs the body's ability to properly control blood clotting or coagulation.
- Duchenne Muscular Dystrophy is an X-Linked Recessive disorder that gradually weakens the body's muscles.
- Lesch-Nyhan Syndrome - X-Linked Recessive Disorder that causes uric acid buildup in all bodily fluids as well as moderate mental retardation and poor muscle control.
Gene Mutations - some genetic problems are caused by a single gene that's present but altered in some way, but often all chromosomes are present. DNA screening techniques are use to detect specific gene abnormalities.
- Cystic Fibrosis (CF) is a progressive genetic disorder that affects the entire body, but especially the lungs and digestive system.
- Tay-Sachs Disease is an autosomal recessive genetic disorder. It's most common variant is infantile Tay-Sachs disease which causes a relentless deterioration of mental and physical abilities beginning at age six months. Death by age four is standard.
- Sickle Cell Anemia is an autosomal recessive genetic blood disorder caused by a mutation in the hemoglobin gene. Sickle cell anemia is characterized by blood cells that assume an abnormal, rigid sickle shape.
- Achondroplasia Dwarfism - a bone growth disorder in which the bones are severely shortened. It is the most common type of dwarfism.
Additional Resources for High Risk Pregnancy:
Sidelines: non-profit organization providing international support for women and their families experiencing complicated pregnancies and premature births.
Hope for Two the Pregnant with Cancer Network: offers free support for women diagnosed with cancer while pregnant. We connect women who are currently pregnant with cancer with other women who have experienced a similar cancer diagnosis.
Lupus Foundation of America: Information for women with lupus who are pregnant or considering pregnancy.
When Your Baby Has A Birth Defect: 150,000 babies a year are born with birth defects. This article from KidsHealth.org has information for how to cope if your child is born with a birth defect.
What Are Genetic Disorders? A library of genetic disorders put together by the University of Utah. Fascinating, informative stuff.
Twin to Twin Transfusion Syndrome Foundation: a nonprofit focused on providing educational resources and other support to families, medical professionals, and caregivers.
Congenital Heart Information Network provides information, resources, and support for families.