“German Measles” in pregnant women is considered very dangerous for the fetus because this disease can cause fetal disabilities or death by infection during pregnancy through the placenta, or death after birth due to infection during delivery through the mother’s secretions or blood during labor. This also includes the mother’s breast milk after delivery. The severity of German measles depends on the virulence of the virus, the duration of infection, and the immune status of both the mother and the fetus.
German measles is a significant viral infectious disease problem. Although vaccination has become more widespread, infections are still found among adolescents, reproductive-age individuals, and pregnant women, leading to a major issue: congenital disabilities. The rubella virus can be transmitted through direct contact with secretions from the nose and mouth of an infected person. The incubation period is approximately 14-21 days after exposure, with the contagious period starting 7 days before the rash appears and lasting until 7 days after the rash appears.
Symptoms of German Measles
Common symptoms include low-grade fever, muscle pain, headache, red eyes, and sore throat. Then, a small red rash appears along with swollen lymph nodes, especially behind the ears and in the neck area. Additionally, it is found that 1 in 3 rubella infections show no symptoms at all.
Risks and Severity
Statistics show that about 0.1-0.2% of pregnant women get infected with rubella. Transmission from mother to fetus can occur during pregnancy. The severity of the disease and fetal disabilities depend on the gestational age at the time of infection, which can lead to miscarriage, fetal death, or congenital disabilities. However, some fetuses do not get infected and have no disabilities. Congenital disabilities are most severe when infection occurs during the first trimester of pregnancy.
Chance of Fetal Infection
It is found that fetuses have up to an 80% chance of infection, but the rate decreases as gestational age increases, with about 54% at 13-14 weeks and 25% after the second trimester. This is because as gestational age increases, more immunity is transferred from mother to fetus.
However, fetal rubella infection does not cause disabilities in all cases. Congenital disabilities found include eye abnormalities (cataracts, glaucoma, microphthalmia), heart defects, hearing impairment, intrauterine growth retardation, enlarged spleen with low platelets, anemia, liver issues, and chromosomal abnormalities. Prevention of rubella can be done by vaccination at least 3 months before pregnancy.
Abnormalities Associated with Congenital Rubella Infection
Abnormalities associated with congenital rubella infection can be divided into three main groups:
-
- Temporary abnormalities that can be found up to 3 months after birth, including enlarged liver and spleen, jaundice, hemolytic anemia, low platelets, and pneumonia.
- Permanent abnormalities, including hearing impairment, congenital heart defects, eye abnormalities, brain abnormalities, and intellectual disability, found in 10-20% of cases.
- Late-onset abnormalities, where no symptoms are present at birth but appear later in 10-30 years, found in about 1 in 3 infected infants.
Common abnormalities include endocrine disorders such as thyroid disease, diabetes, and growth hormone deficiency, as well as hearing and vision impairments, vascular abnormalities, and hypertension. Brain abnormalities are often found in infants whose mothers were infected during the first trimester.
Diagnosis of German Measles
Rubella infection symptoms can be difficult to observe and have low accuracy because these symptoms can also be found in other infectious diseases. Pregnant women with a history of exposure or symptoms resembling rubella before 16 weeks of gestation should be tested to confirm rubella infection to assist in further management. In practice, laboratory tests measuring Immunoglobulin levels are used. Testing for IgM Specific Antibody can detect infection from day 5 after rash onset and remains positive for 4-6 weeks, helping to confirm diagnosis. There are also reports of virus isolation from saliva and throat swabs.
Diagnosis of Rubella Infection
Prenatal diagnosis is important, especially if rubella infection is suspected during the first trimester and maternal test results are inconclusive. Additional testing can be done by measuring IgM in the infant’s blood, collected directly from the umbilical cord, since IgM does not cross from mother to fetus. This test can be done 7-8 weeks after maternal infection and at 20-22 weeks of gestation.
Amniotic fluid testing can be performed with a lower risk of miscarriage but is more complicated in fetuses. Virus isolation and reliability are relatively low. Confirmation testing in newborns suspected of infection is usually done if the mother has a history of infection or diagnosis during pregnancy. Pregnant women with a history of exposure or symptoms should be tested immediately. If infection is detected, the mother should be counseled about the risks and congenital disabilities of the fetus, and fetal infection should be confirmed by testing the infant’s blood or amniotic fluid.
After maternal infection is confirmed, if fetal infection is also present, the mother should receive counseling about the risk of congenital disabilities and pregnancy termination if infection occurs during the first trimester. Immunoglobulin administration after maternal exposure currently has no evidence of reducing fetal infection and is not recommended for asymptomatic newborns. However, newborns should be isolated from healthy infants for observation and assessment of possible later abnormalities.
Preconception Planning to Prevent Risks
For prospective parents planning a family before marriage, if unsure about immunity against rubella, including spouses planning to travel abroad, honeymoon, or visit countries with high rubella outbreaks, obstetricians recommend consulting a specialist for diagnosis and immunity testing to ensure protection against rubella.
Rear Admiral Dr. Sosakul Boonyawiroj
Gynecologic Oncology Specialist
Women’s Health Center, Phyathai 1 Hospital
