What is Urinary Tract Infection in Pregnancy (UTI in Pregnancy)?
During pregnancy, the structure of the urinary system changes a lot due to hormonal and mechanical reasons. These changes may lead to the stretching of the tubes that carry urine from the kidneys to the bladder (ureters), widening of the kidney’s internal cavities (renal calyces), and slow or stalled movement of urine, all making pregnant women more prone to urinary tract infections (UTIs). The hormone progesterone relaxes the muscles, and the growing womb puts pressure on the bladder, reducing its capacity. This can result in a condition where urine flows back from bladder to kidneys (vesicoureteral reflux), urine left in the bladder after urination (residual urine), and slow or stalled urine movement. All these changes can increase the risk of UTIs during pregnancy.
Usually, UTIs in pregnancy start with the presence of bacteria in the urine without symptoms (asymptomatic bacteriuria). If not treated, this can develop into an infection with symptoms, like bladder infection (cystitis) or kidney infection (pyelonephritis). Infections often spread from the lower urinary system upwards, aided by weakened muscles around the bladder and changes in bladder function due to pregnancy. It’s important for healthcare professionals to understand these aspects so they can effectively identify, diagnose, and treat UTIs in pregnancy. By doing so, they can prevent complications and make sure both the mother and baby stay healthy.
What Causes Urinary Tract Infection in Pregnancy (UTI in Pregnancy)?
Urinary tract infections (UTIs) during pregnancy can happen for a number of reasons, mainly linked to the physical and hormonal changes that happen in a woman’s body when she’s expecting a baby.
One significant factor is changes in hormone levels, particularly the increase in progesterone. This hormone relaxes the muscles in the urinary tract, including those in the tubes that carry urine from the kidneys to the bladder (the ureters) and in the bladder itself. This makes it easier for bacteria to travel upwards from the tube through which urine leaves the body (the urethra) into the bladder, and potentially even to the kidneys.
In addition, as the uterus (the womb) grows bigger, it can block the ureters and the flow of urine, making pregnant women more prone to getting UTIs. Hormonal changes can also alter the balance of bacteria in and around the vagina, which can lead to more harmful bacteria being present.
Another factor is changes to the immune system during pregnancy, such as a reduction in the type of immunity that involves cells, which might weaken the body’s ability to fight off bacterial infections effectively. Combined, all of these factors can make the development of UTIs more likely during pregnancy. This highlights the need for pregnant women to take steps to prevent and manage these infections to protect not only their own health, but also the health of their unborn baby.
Risk Factors and Frequency for Urinary Tract Infection in Pregnancy (UTI in Pregnancy)
Urinary Tract Infections (UTIs) during pregnancy can be divided into two main categories: lower and upper urinary tract infections. In the lower category, we find conditions known as asymptomatic bacteriuria and cystitis. In the upper category, there’s a condition called pyelonephritis.
These categories have been identified by the World Health Organization (WHO), which reports that infections during pregnancy contribute to 10.7% of pregnancy-related maternal deaths worldwide. As many as 28% of these are found to be UTIs. The most common cause for cystitis and pyelonephritis, particularly during pregnancy, is a condition termed Asymptomatic Bacteriuria (ASB). This means that there are more than 100,000 organisms per milliliter in a urine test, but the patient does not show any symptoms.
If ASB is left untreated in pregnancy, it can lead to other UTIs in about 25% of cases. Around 5% to 6% of non-pregnant women usually have ASB, similar to the 2% to 10% seen during pregnancy. It is also more common among women who have given birth previously and those from low socioeconomic backgrounds. Additionally, carriers of the sickle cell trait are more likely to have ASB.
Given the high occurrence and serious potential consequences of pyelonephritis, prenatal guidelines generally suggest that all pregnant people should be checked for ASB early in their prenatal care. This is usually done with a basic urine culture test. Conventionally, it was believed that treating ASB can cut down the risk of clinical infections to 3% – 4%. However, recent studies challenge this notion, showing that treating ASB doesn’t necessarily reduce the chances of preterm birth and low birth weight. Clearly, more research is needed in this area.
- Cystitis affects 1% to 2% of pregnant individuals.
- Pyelonephritis also impacts 1% to 2% of pregnant people, and it’s more common in the second trimester.
- Pyelonephritis can lead to serious infections, including septic shock, and is often the cause of most medical hospitalizations during pregnancy.
- In one study, UTIs accounted for 3.5% of all hospital admissions before childbirth.
- Risk factors for pyelonephritis during pregnancy include obesity, low socioeconomic status, being a young mother, having diabetes, smoking, and a history of recurrent UTIs.
- Pyelonephritis is typically right-sided, but it may affect both sides in up to 25% of cases.
Signs and Symptoms of Urinary Tract Infection in Pregnancy (UTI in Pregnancy)
Asymptomatic bacteriuria (ASB) is a condition in which there are bacteria in the urine but no symptoms of a urinary tract infection (UTI). Those having frequent UTIs or a history of ASB in a previous pregnancy are at risk to develop this disease. Hence, early screening in pregnancy is vital. Individuals with sickle cell trait may require more frequent screening during pregnancy, though no standard practice is defined for them. However, more frequent screening is not advisable for those with spinal cord injuries or diabetes, as it can cause more harm.
Cystitis, or bladder infection, causes similar symptoms in pregnant and non-pregnant individuals. These symptoms include a painful or burning sensation during urination, frequent urination, urgent need to urinate, and lower abdominal pain. However, these symptoms alone can be misleading, as only about one-fourth of women reporting such symptoms actually have a confirmed UTI based on a urine culture result.
- Painful or burning sensation during urination
- Frequent urination
- Urgent need to urinate
- Lower abdominal pain or tenderness
Observing similar symptoms in pregnant and non-pregnant patients, pyelonephritis or kidney infection presents with flank pain, fever above 38.0°C, and chills. Patients may also experience less specific symptoms, such as fatigue, loss of appetite, nausea, vomiting, etc. These symptoms can often be mistaken for other abdominal conditions or pregnancy-related complications.
- Flank pain
- Fever above 38.0 °C
- Chills
- Fatigue
- Loss of appetite
- Nausea
- Vomiting
It’s also common for patients to report or show signs of contractions due to muscle irritability from infection. If contractions are noticed, the pregnancy should be evaluated for preterm labor, and the patient should be monitored closely. There can also develop signs of sepsis, like a fast heartbeat and low blood pressure, requiring immediate attention.
During a physical exam, the doctor should focus on checking vital signs, heart, and lungs. The exam will likely include pressing on the abdomen to locate any tenderness and checking the lower back area for pyelonephritis. A genitourinary exam will assess any cervical infection and check for cervical dilation upon admission. It’s important to continue monitoring for contractions and any other abnormalities throughout the hospital stay, even if there are no immediate concerns about pregnancy complications.
Testing for Urinary Tract Infection in Pregnancy (UTI in Pregnancy)
If a pregnant individual has concerns about a urinary tract infection, or UTI, a clean-catch urinalysis and urine culture will typically be carried out. However, the following should be considered: some tests may be less accurate if the patient is well-hydrated and the urine is diluted. Blood presence in the urine could result from contamination during the collection process. Protein may also be found in pregnant women’s urine due to reduced protein absorption or contamination, such as from vaginal discharge.
Pregnant individuals should note that urine dipstick screening, a quick test to check for an infection, tends to give a high number of false positives and is generally not beneficial. If symptoms are present, other factors, like the detection of nitrites and the presence of certain symptoms can be quite effective in predicting a UTI. However, they are less reliable when it comes to ruling out this condition.
It’s also common to get contaminated urine samples during pregnancy. Larger body mass index (BMI) increases the risk of having dirty urine cultures. What’s interesting is that having the patient perform a cleaning process doesn’t necessarily make the sample less polluted. Once the culture turns out negative, the chance of developing a more severe kidney infection is low.
If there is a suspicion of a kidney infection during pregnancy, blood tests should be carried out to assess the general health, electrolyte levels, and kidney function. Additional tests may be needed to eliminate other possible causes for the symptoms, like pancreatitis. And in cases where sepsis, a life-threatening reaction to an infection, is suspected, lactic acid and blood cultures should be done as quickly as possible and even before starting antibiotics.
Additionally, if the fetus is at a stage where it could potentially live outside the womb, monitoring of the fetal heart rate and contractions should be done. It might also be useful to take samples of the cervix and group B strep on admission in case complications with the pregnancy occur. Sometimes, a kidney ultrasound might be needed to look for a possible kidney abscess.
Treatment Options for Urinary Tract Infection in Pregnancy (UTI in Pregnancy)
In pregnancy, acute asymptomatic bacteriuria (ASB) and acute cystitis (a type of urinary tract infection or UTI) are treated with oral antibiotics. Typically, treatment starts if a harmless bacteria reaches levels of 100,000 or more per milliliter in a urine culture. If the patient is experiencing symptoms like frequent urination, pain during urination, or blood in the urine, doctors might begin treatment even before the culture results are available.
While amoxicillin and ampicillin might be the initial choices, there is widespread resistance from E.coli, a common cause of UTIs. Therefore, other antibiotics such as cephalosporins, nitrofurantoin, fosfomycin, and trimethoprim-sulfamethoxazole are usually used. Fluoroquinolones, however, are not recommended as an initial treatment because of conflicting studies regarding their safety during pregnancy.
Recent studies suggest a link between certain antibiotics like sulfa derivatives and nitrofurantoin and birth defects when used in the first trimester. While these studies have limitations, it is generally recommended to avoid these medications in the first months of pregnancy whenever possible.
If a UTI in pregnancy becomes severe, developing into pyelonephritis (a kidney infection), it is usually treated in the hospital with intravenous antibiotics and fluids. Second or third-generation cephalosporins are commonly used in these cases, but aminoglycosides or other broad-spectrum antibiotics may also be used. If the patient had shown resistance to cephalosporins in the past, carbapenems are usually the first choice.
The type of antibiotic used may be changed once the type of bacteria causing the infection is known. Patients are carefully monitored for symptoms of worsening sepsis. After the patients symptoms improve, they are often transitioned to oral antibiotics to complete a 7 to 14-day treatment, followed by suppressive therapy for the rest of the pregnancy.
Finally, it’s important to note that there is limited guidance on what to do after UTI treatment in pregnancy. Some doctors may request a repeat urine culture 1 to 2 weeks after treatment, or they may just monitor the patient for reappearance of symptoms. As of now, there is not enough evidence to suggest the use of daily antibiotics to prevent future UTIs.
What else can Urinary Tract Infection in Pregnancy (UTI in Pregnancy) be?
When diagnosing urinary tract infections (UTIs) during pregnancy, doctors need to consider other conditions that can cause similar symptoms. To get an accurate diagnosis and make sure the right treatment is given, it’s essential to carry out a detailed checkup. For pregnant women, common UTI symptoms like painful urination, frequent urination, a constant need to urinate, and pain in the lower part of your tummy, might be due to normal changes during pregnancy. For instance, as the womb grows, it can put pressure on the bladder, leading to the increased need to urinate.
Other conditions like pelvic inflammatory disease, vaginal infections, and sexually transmitted infections can also cause similar symptoms to UTIs during pregnancy. Additionally, when diagnosing kidney infection (a severe type of UTI) during pregnancy, doctors will also consider other health problems such as appendicitis, pancreatitis, gallbladder inflammation, and kidney stones. Pregnancy-related complications like preterm labor, inflammation of the fetal membranes (chorioamnionitis), or detachment of the placenta from the uterus (placental abruption) can also be considered as possible causes of similar symptoms.
What to expect with Urinary Tract Infection in Pregnancy (UTI in Pregnancy)
The outcome for pregnant individuals with urinary tract infections (UTIs) greatly depends on how quickly and effectively they are diagnosed and treated. When UTIs are left untreated or not properly treated, they can lead to serious complications, such as kidney infections, premature birth, low birth weight, and serious infections that can affect both the mother and baby’s health. But with early diagnosis, appropriate antibiotics, and regular monitoring, most pregnant people with UTIs can expect a positive outcome.
In the past, doctors regularly tested for bacteria in urine that doesn’t cause symptoms (known as asymptomatic bacteria, or ASB) during pregnancy. Since this practice started in the 1960s and 70s, kidney infections during pregnancy have decreased from 20-35% to 1-4%. However, it’s unclear if treating ASB also reduced preterm births and instances of low birth weight infants because the studies providing this data are outdated. Recent studies have begun to question the need for ASB screening and treatment during pregnancy, finding that it may not actually reduce the rates of preterm birth and low birth weight.
Finally, it’s important to consider the potential for overuse of antibiotics in pregnant women. Research has shown that antibiotics, particularly for treating ASB, are used more frequently in Europe and Asia compared to other regions. This excessive use of antibiotics could lead to an increase in bacteria that are resistant to these drugs, such as specific strains of E. coli and Klebsiella pneumonia.
Possible Complications When Diagnosed with Urinary Tract Infection in Pregnancy (UTI in Pregnancy)
Urinary Tract Infections (UTI) during pregnancy can lead to a range of complications. These include blood poisoning (sepsis), low red blood cell count (anemia), shortness of breath and low oxygen levels (Acute Respiratory Distress Syndrome), widespread blood clotting within blood vessels (disseminated intravascular coagulopathy), early contractions and labor, kidney abscesses and a need for intensive care. Studies suggest that a number of pregnant women experiencing a kidney infection (pyelonephritis) may have bacteria in their blood, sepsis, or even septic shock. Notably, preterm labor and lower birth weights are also potential complications of a UTI during pregnancy.
Lungs can be affected too, with up to 10% of pregnant women being treated for kidney infection experiencing complications like fluid accumulation in lungs or ARDS due to harmful substances released by bacteria (endotoxins). Close observation of urine output and oxygen levels is vital, and some may need intensive care for breathing support. These endotoxins may also lead to anemia, which usually gets better after treatment and is the most common complication cases seen with kidney infections. They could also trigger early contractions, warranting careful surveillance for early labor and delivery.
- Sepsis
- Anemia
- Acute Respiratory Distress Syndrome
- Disseminated intravascular coagulopathy
- Early contractions and labor
- Kidney abscesses
- Intensive care requirement
- Pulmonary or lung complications
- Low birth weight
- Prominent risk of premature delivery
A few may have a persistent infection which could be indicative of a urinary blockage or a kidney abscess, and might call for a reassessment of the antibiotics being used. In some instances, pregnant women may have repeated UTIs, and managing this can be tricky due to limited data. However, it’s common to suggest suppressive antibiotic therapy throughout pregnancy in women who had recurrent UTIs during pregnancy. Antibiotics like nitrofurantoin or cephalexin are typically used in such cases.
Preventing Urinary Tract Infection in Pregnancy (UTI in Pregnancy)
Preventing urinary tract infections (UTIs) during pregnancy is crucial to the health of both the mother and the unborn child. Prevention strategies include habits like regular handwashing and proper care of the genital area to lower the chances of bacteria spreading and causing an infection. It’s also important to encourage pregnant women to drink enough water and empty their bladder frequently to prevent urine from staying in the bladder too long, decreasing the chance of getting a UTI.
Another preventive measure is checking for UTIs that don’t show any symptoms during regular prenatal visits. If found, these should be treated quickly to keep the infection from getting worse. Education is key in helping pregnant women understand the symptoms of UTIs, so they can seek medical help promptly if needed.
Additionally, using proven guidelines for antibiotics can help prevent more UTIs in pregnant women at high risk. By focusing on these preventive measures and educating patients, healthcare professionals can lessen the impact of UTIs during pregnancy. This, in turn, helps ensure the best possible health for the mother and child.
