Scientists talked about the relationship between repeated screening and the risk of premature birth

Premature birth can be associated not only with the health of the expectant mother, but also with infections, which often occur without noticeable symptoms. Therefore, a single examination during pregnancy may not be enough to detect some of them in a timely manner. A study in South Africa found that repeated screening for three common infections was associated with a reduced risk of having a baby prematurely. About why scientists propose to pay more attention to examinations during pregnancy — in the material of Izvestia.

Two tests instead of one

The results of the study are published in the journal Clinical Infectious Diseases. 2,247 pregnant women from four public health institutions in South Africa participated in the work. The participants were randomly divided into three groups: the first was tested for infections at the beginning of pregnancy, the second was tested twice at the beginning of the study and again at 30-34 weeks, the third received standard medical care, in which infections were detected and treated when symptoms appeared.

The scientists tested for three sexually transmitted infections: chlamydia, gonorrhea, and trichomoniasis. All of them can be asymptomatic, so a person does not always know about their presence. At the same time, infections can cause inflammation of the genital tract and create risks for the course of pregnancy.

In the groups undergoing the examination, molecular tests were used to identify pathogens. If the result was positive, the participants were offered treatment. Thus, the researchers tested not only the benefits of diagnosis, but also the effectiveness of a strategy in which infections are detected and treated repeatedly throughout pregnancy.

Infections without symptoms

At the first examination, at least one of the three infections was found in about 27% of the participants. About 80% of the identified cases were symptom-free. This means that most of the women might not have been aware of the infection, as they did not experience any characteristic discomfort or other noticeable symptoms.

Repeated testing at the age of 30-34 weeks also revealed infections: 9.2% of the surveyed received a positive result. This could be due to the persistence of infection after initial treatment, re-infection, or the appearance of a new infection during pregnancy. However, according to the results of the study, it is impossible to determine the reason for each repeated positive test.

The authors note that a single examination does not always reveal all the infections that may occur or persist during pregnancy. Repeated check-up provides an additional opportunity to detect them and prescribe treatment before delivery.

The risk of childbirth decreased by 23%

Among the women who were examined twice, premature birth occurred in 14.5% of cases. In the standard medical care group, this figure was 18.8%, and among the participants who underwent only one examination, it was 18.9%. Thus, repeated testing was associated with a 23% reduction in the relative risk of premature birth compared to standard care.

However, the results were not the same for all the assessed indicators. The main criterion of effectiveness in the study was a combination of two outcomes: premature birth and the birth of a child with a low body weight. No statistically significant improvement was found for this combined indicator. A separate analysis also did not reveal a significant decrease in the birth rate of children with low body weight.

Scientists have explained the deterioration of memory during pregnancy

Why infections are dangerous for pregnancy

Chlamydia, gonorrhea, and trichomoniasis can cause inflammatory processes in the genital tract. During pregnancy, infection and the associated inflammatory response can affect the tissues and mechanisms involved in maintaining pregnancy. In particular, inflammatory signals can contribute to the processes associated with the onset of labor.

However, the study does not prove that it was inflammation that caused the differences in the frequency of premature birth between the groups. The scientists evaluated the results of the examination and pregnancy outcomes, but did not establish a specific biological mechanism that explains the effect.

There are other limitations. The work was carried out in one region of South Africa, where the prevalence of the studied infections was high. Therefore, the results cannot be automatically transferred to countries and population groups with a different epidemiological situation. The authors believe that additional research is needed to determine the optimal timing and frequency of examinations.