Maternal Infections

When a mother develops an infection during pregnancy, it can affect not only her own health but also her developing baby. Understanding which infections pose risks, how they spread, and what can be done to prevent or treat them is essential for protecting both mother and child. Some maternal infections, if left undiagnosed or untreated, can lead to serious complications including preterm birth, developmental delays, and birth injuries that affect a child for life.

This page explains what maternal infections are, which types are most concerning during pregnancy, how they are detected and treated, and what families can do to reduce risk and find support if complications arise.

What Are Maternal Infections?

Maternal infections are infections that occur in a pregnant woman and have the potential to affect both her health and the health of her baby. These infections can be caused by bacteria, viruses, fungi, or parasites. While many infections are common and treatable, pregnancy changes the way a woman’s immune system functions, which can make some infections more severe or harder to fight off.

Certain infections are particularly dangerous because they can cross the placenta and directly harm the developing fetus, leading to congenital abnormalities, preterm delivery, or serious illness in the newborn. Others may not affect the baby during pregnancy but can be transmitted during labor and delivery, causing infection shortly after birth.

Types of Maternal Infections

Maternal infections fall into several categories based on what causes them.

Bacterial Infections

Bacterial infections are among the most common and include:

• Group B streptococcus (GBS)
• Chorioamnionitis (infection of the amniotic sac and fluid)
• Urinary tract infections (UTIs)
• Bacterial vaginosis
• Listeria
• Syphilis
• Gonorrhea
• Chlamydia

Many bacterial infections respond well to antibiotics, especially when caught early. Group B streptococcus, for example, is routinely screened for late in pregnancy so that antibiotics can be given during labor to protect the baby.

Viral Infections

Viral infections can be more difficult to treat and may require antiviral medications or careful monitoring. Common viral infections during pregnancy include:

• Influenza
• Cytomegalovirus (CMV)
• Herpes simplex virus (HSV)
• Hepatitis B
• HIV
• Zika virus
• Varicella (chickenpox)

Some of these, like CMV and Zika, are known to cause birth defects. Others, like herpes, can be transmitted to the baby during delivery and require specific precautions and, in some cases, cesarean birth.

Parasitic Infections

Parasitic infections are less common in the United States but still pose significant risks:

• Toxoplasmosis (often from undercooked meat or cat litter)
• Malaria (in areas where it is endemic)

Both can cross the placenta and harm the developing baby.

Fungal Infections

Candidiasis, commonly known as a yeast infection, is the most frequent fungal infection during pregnancy. While usually not harmful to the baby, it can cause discomfort and may require treatment before delivery.

TORCH Infections

Medical professionals often refer to a group of infections by the acronym TORCH, which stands for:

• T – Toxoplasmosis
• O – Other infections (including syphilis, varicella-zoster, parvovirus B19)
• R – Rubella (German measles)
• C – Cytomegalovirus
• H – Herpes simplex virus

These infections are particularly important because they can directly affect fetal development and cause congenital anomalies. Screening for TORCH infections is a standard part of prenatal care in many cases, especially when there are symptoms or risk factors present.

How Maternal Infections Affect Pregnancy and the Baby

The impact of a maternal infection depends on the type of infection, when it occurs during pregnancy, and how quickly it is treated. Some infections cause mild symptoms in the mother but serious harm to the baby. Others may make the mother very sick and indirectly affect the pregnancy.

Risks to the Mother

Untreated infections can lead to severe illness, hospitalization, and in rare cases, maternal death. Infections like sepsis or severe influenza require urgent medical care. Even less severe infections can cause discomfort, complicate delivery, or lead to postpartum complications.

Risks to the Baby

Maternal infections can lead to:

• Preterm labor and delivery
• Low birth weight
• Stillbirth or neonatal death
• Congenital anomalies such as hearing loss, vision impairment, microcephaly, hydrocephalus, or heart defects
• Neonatal sepsis or meningitis
• Developmental delays and intellectual disabilities

Chorioamnionitis, an infection of the tissues surrounding the baby, is one of the most concerning infections during labor. It increases the risk of neonatal brain injury, cerebral palsy, and sepsis. Prompt recognition and treatment with antibiotics are critical to reducing these risks.

Recognizing the Symptoms

Symptoms of maternal infection vary widely depending on the type and severity of the infection. Some infections cause no symptoms at all, which is why routine prenatal screening is so important.

Common warning signs include:

• Fever, chills, or night sweats
• Painful or frequent urination
• Lower abdominal or pelvic pain
• Unusual, foul-smelling, or bloody vaginal discharge
• Rash or skin lesions
• Jaundice (yellowing of the skin or eyes)
• Swollen lymph nodes
• Preterm contractions or rupture of membranes before labor

If any of these symptoms occur during pregnancy, it is important to contact a healthcare provider right away. Early diagnosis and treatment can prevent complications.

How Maternal Infections Are Diagnosed

Diagnosis typically involves a combination of medical history, physical examination, and laboratory testing. Healthcare providers look for signs of infection and use tests to confirm the diagnosis and identify the specific cause.

Common diagnostic tools include:

• Blood tests (to detect antibodies against, or direct evidence of, infection)
• Urine cultures (to diagnose urinary tract infections)
• Vaginal or cervical swabs (to test for GBS, chlamydia, gonorrhea, or bacterial vaginosis)
• PCR testing (to identify viral DNA or RNA)
• Ultrasound (to assess fetal development and look for signs of infection or abnormalities)
• Fetal heart rate monitoring (to check for signs of distress)

Prenatal screening programs are designed to catch infections early, even before symptoms appear. Universal screening for infections like syphilis, HIV, hepatitis B, and Group B strep is now standard practice in the United States.

Preventing Maternal Infections

Many maternal infections can be prevented or their impact reduced through proactive steps during and before pregnancy.

Prenatal Screening and Early Detection

Following the recommended schedule of prenatal visits allows healthcare providers to screen for infections at key points in pregnancy. The CDC and the American College of Obstetricians and Gynecologists (ACOG) recommend universal screening for:

• HIV
• Hepatitis B
• Syphilis
• Group B streptococcus (late in pregnancy)
• Urinary tract infections

Additional testing may be recommended based on symptoms, travel history, or other risk factors.

Vaccination

Vaccines are one of the most effective ways to prevent infections. Some vaccines are safe and recommended during pregnancy, while others should be given before conception.

Vaccines recommended during pregnancy include:

• Influenza vaccine (flu shot)
• Tdap (tetanus, diphtheria, and pertussis) vaccine, usually given in the third trimester

Vaccines that should be given before pregnancy if a woman is not already immune include:

• MMR (measles, mumps, rubella)
• Varicella (chickenpox)

Women who are planning to become pregnant should discuss their vaccination history with their healthcare provider.

Good Hygiene and Safe Practices

Simple steps can reduce the risk of infection:

• Wash hands frequently, especially before eating and after using the bathroom
• Avoid undercooked meat, unpasteurized dairy, and deli meats (to prevent listeriosis)
• Do not clean cat litter boxes or handle soil without gloves (to prevent toxoplasmosis)
• Practice safe sex and get tested for sexually transmitted infections
• Avoid contact with people who have contagious illnesses when possible

Prompt Treatment

When infections are detected, timely treatment is essential. Bacterial infections often respond well to antibiotics. Some viral infections can be managed with antiviral medications. Even infections that cannot be cured can often be managed to reduce the risk to the baby.

For example, women with HIV who receive antiretroviral therapy during pregnancy and delivery have a very low risk of transmitting the virus to their baby. Similarly, women who test positive for Group B strep receive antibiotics during labor to protect the newborn.

Standards of Medical Care

Healthcare providers follow evidence-based guidelines to manage maternal infections and protect both mother and baby.

Screening and Monitoring

The CDC, ACOG, and the World Health Organization (WHO) all recommend early and comprehensive screening during pregnancy. This includes:

• Testing for sexually transmitted infections at the first prenatal visit
• Screening for Group B strep between 36 and 37 weeks of pregnancy
• Testing for gestational diabetes and other conditions that may increase infection risk

Treatment Protocols

When an infection is diagnosed, treatment is guided by the type and severity of the infection.

• Bacterial infections such as UTIs, GBS, and chorioamnionitis are treated with intravenous or oral antibiotics
• Viral infections like herpes or HIV are managed with antiviral medications
• Parasitic infections like toxoplasmosis may be treated with antiparasitic drugs

In cases of chorioamnionitis or other serious infections during labor, immediate antibiotic therapy is critical to prevent neonatal sepsis and brain injury.

Multidisciplinary Care

Complex infections often require a team approach. Maternal-fetal medicine specialists, infectious disease doctors, neonatologists, and other experts may work together to manage the infection and monitor the baby’s health.

Outcomes and Statistics

Despite advances in screening and treatment, maternal infections remain a significant cause of complications during pregnancy and childbirth.

Globally, infections are a leading cause of maternal and newborn illness and death. In the United States, infections such as sepsis are among the top five causes of pregnancy-related deaths. In New York City, sepsis and other infectious complications are closely monitored as part of efforts to reduce maternal mortality.

For newborns, untreated or improperly managed maternal infections increase the risk of:

• Neonatal sepsis
• Meningitis
• Birth injuries such as hypoxic-ischemic encephalopathy
• Cerebral palsy
• Developmental delays

Early detection, appropriate treatment, and close monitoring can significantly reduce these risks.

Support for Families

When a maternal infection leads to complications, families may face a difficult and emotional journey. Understanding what happened, what to expect, and where to find help can make a meaningful difference.

Education and Awareness

Learning about the infection, its potential effects, and the available treatments helps families feel more informed and empowered. Healthcare providers should take time to explain diagnoses, answer questions, and discuss next steps.

Access to Specialists

Babies affected by maternal infections may need follow-up care with pediatric specialists, including neurologists, developmental pediatricians, and therapists. Early intervention services can support children who experience developmental delays or birth injuries.

Emotional and Social Support

Coping with a difficult pregnancy or a baby’s health challenges can be overwhelming. Support groups, counseling, and connections with other families who have been through similar experiences can provide comfort and practical advice.

Long-Term Care and Monitoring

Some children affected by maternal infections will need ongoing medical care, therapy, or educational support. Working closely with a care team and staying informed about available resources can help families navigate these needs.

At NYBirthInjury.com, we provide trusted information to help families understand birth injuries, medical care, and the support options available in New York and across the United States. Our goal is to offer clear, compassionate guidance during challenging times.

Moving Forward From Maternal Infections

Maternal infections are a serious but often preventable cause of complications during pregnancy and childbirth. Routine prenatal care, timely screening, vaccination, and prompt treatment can protect both mothers and babies from harm.

If you have concerns about a possible infection during pregnancy, or if your child has been affected by a maternal infection, it is important to seek medical advice and support. Understanding the facts, knowing the warning signs, and staying informed can help ensure the best possible outcomes for you and your family.