A cervical cerclage success rate of 94% in our study suggests the validity of testing bacteriological cultures both before the procedure and in the subsequent course of pregnancy. Targeted antibiotic therapy allows for effective eradication of pathogens. The procedure used by our team to control the microbiological status of the cervical canal allowed us to obtain better or similar results to those reported by other authors [10, 12, 13, 14, 15] both in terms of maintenance of pregnancy up to the 34th and 37th weeks of gestation and neonatal outcomes (incidence of respiratory disorders requiring treatment at birth and neonatal deaths at birth). The evaluation of the children's development, which has not yet been done by any of the cited authors, allows us to assume that the adopted scheme of management yields more than satisfactory results.
Any pregnancy loss is a heavy burden on a woman. Lee's analysis shows that women with one lost pregnancy in the second trimester demonstrate rates of successful pregnancies after cervical cerclage placement in a subsequent pregnancy similar to those of women with a history of two lost pregnancies. This result justifies cerclage placement after the first pregnancy loss and is consistent with current recommendations. In the cited study, 74% delivered no earlier than in the 37th week .
A study by Chen describing the obstetric outcomes of patients after PCC and UCC placement reported a neonatal survival rate that was not significantly different from that obtained in our study (86.9% vs. 94.2% in our group) . However, in our study group, significantly more patients continued pregnancy beyond 36 weeks (55% vs. 80%), which may implicate neonatal complications. In the cited study, cultures were performed only in direction of Group B Streptococcus (GBS), and the choice of antibiotic therapy was dependent on the opinion of the treatment team. Among the patients included in the study preoperative cultures were taken from 48 pregnant women, of whom 12 had abnormal results.
Similar to our study, Moisidis-Tesch et al. demonstrated a wide variety of pathogens residing in the cervical canal before the cervical cerclage placement procedure. In the cited studies, bacteria were found in 53% of the samples collected . Among the 45 pathogens detected, the predominant were Enterococci (31%) and E. coli (27%). In the study cited above, GBS, which is the bacterium most frequently detected in other studies, accounted for only 6.7% of detected bacteria, which indicates the futility of limiting the collected swabs to only this pathogen. In the case of discovering cervical colonization, the patients would receive treatment consistent with the antibiogram for at least 24–48 hours before the procedure. No cultures were obtained to assess the effectiveness of therapy, and no cultures were obtained later in pregnancy. The article does not provide information on fungal determination. In our study group, Candida spp. was the most common pathogen in cultures of patients before the procedure and the third most common pathogen in swabs taken later in pregnancy. Moisidis-Tesch et al. found that the only antibiotics to which all cultured pathogens show sensitivity are vancomycin and imipenem which are antibiotics reserved for severe infections. These drugs are not applicable in the treatment of fungal infections, which were probably not considered by the authors . Based on our experience, it seems preferable to always collect cultures and select drugs according to the antibiogram. In the study by Wang , despite the application of broad-spectrum antibiotics for 5 days after cervical suture placement in a group of patients with prophylactic cerclage, statistically fewer women maintained their pregnancies to the 37th week in comparison with our patients (54.9% vs. 80%), while no significant differences were noted in the percentage of patients who maintained their pregnancies to the 34th week (72.9% vs. 88.6% in our group). In the prophylactic cerclage group described by Liu , using perioperative antibiotics without cervical swabs, 60% of patients delivered after the 37th week compared to 80% in our study, and 70% delivered by the 35th week compared to 85% in our study.
During the planning phase of our study the literature suggested that patients with PCC and UCC have similar obstetrical outcomes. Nevertheless it turned out that patients with UCC had worse obstetric outcomes than those with PCC – none of them delivered at term and the only neonatal death occurred in a patient with UCC. On account of that it may be beneficial to investigate these groups separately in the future.
Brown et al.  presented a hypothesis regarding the causes of cervical insufficiency. The first part assumes that the etiology of cervical insufficiency is mechanical “impairment” of the cervix. It seems to us that this group in our study could be represented by 12 patients with normal cervical canal cultures throughout whole pregnancy (before and after the cervical cerclage placement procedure). As many as 11 patients in this group delivered after the 37th week of gestation, despite a history of preterm labor and/or cervical insufficiency. The second part of the hypothesis implies an association between the occurrence of cervical insufficiency and chronic inflammation resulting from colonization of the reproductive tract. In our study, it was possible to distinguish a group of 10 other patients in whom, despite treatment of genital tract colonization before the cervical suture placement procedure, colonization with subsequent pathogens was detected throughout the pregnancy. This group of patients demonstrated the highest rate of preterm deliveries. In our opinion, active eradication of microorganisms colonizing the cervix even during periconceptional care should result in better obstetric outcomes, but further research is needed to prove this thesis. When the patient is already pregnant, active monitoring of cervical cultures is an ad hoc measure, but is the best possible measure in the author’s opinion. The Evidence Report, which included 48 studies analyzing the effect of treatment of asymptomatic bacterial vaginosis (BV) on the incidence of preterm labor, did not show an effect of such treatment on obstetric outcomes (delivery in the 37th week of gestation, pPROM, intrauterine deaths, neonatal mortality) in the group of pregnant patients without history of obstetric problems; however, the results are inconclusive for the group with a history of preterm labor . In mothers, side effects of antibiotic therapy were more common after oral than vaginal administration, with mild side effects such as pruritus or diarrhea predominating in both routes . Similarly, a Cochrane systematic review showed no benefit of treating BV in the general pregnant population, use of antibiotic therapy was associated with a lower risk of pPROM and low birth weight in patients with history of obstetric problems. Furthermore, antibiotic therapy administered before the 20th week of gestation in the general pregnant population correlated with a lower risk of delivery before the 37th week of gestation . We believe that patients at risk of preterm delivery should receive more detailed monitoring of the cervical microbiome.
Romero’s study from 2019 shows that most of pathogens found in the amniotic fluid (75%) are typical vagina commensals and in 62.5% of women with bacteria cultured from their amniotic fluid also had these bacteria present in their vagina. It indirectly proves that the most common way for pathogens to access the uterine cavity is by ascending from vagina. Collecting cervical canal cultures and treating the pathogens according to the antibiogram before as well as after PCC/ UCC procedure is a way of preventing the ascending intrauterine infection .
The available literature on cervical cerclage has not analyzed the endpoint of child development at 2 years of age, making it impossible to compare our results with those of other authors. Over the past 30 years, advances in medical technology in the field of neonatology have enabled a significant increase in the survival rate of premature babies, including extreme preterm infants. Studies of older children indicate that prematurity is an important cause of future complications in the form of neurological disorders. The incidence of cerebral palsy and other forms of cognitive impairment has remained similar despite increased survival rates . In a study of a French cohort of several thousand premature children, the incidence rate of cerebral palsy at two years of age was 4.6% in a group of 3599 children analyzed after two years. However, as many as 50.2% of children born between the 24th and 26th week of gestation, 40.7% of those born between the 27th and 31st week of gestation, and 36.2% of those born between the 32nd and 34th week of gestation, had lower scores on a standardized test assessing normal development at 24 months of age (assessment of gross and fine motor skills, communication skills, problem solving skills and social skills, with the reservation that deaf, blind, and cerebral palsy patients were excluded from the analyses) . In addition, research results show that children born prematurely are more likely to develop chronic diseases, such as asthma, kidney disease, and hypertension [21, 22, 23].
The limitation of our study is the relatively small group of covered patients, which makes it impossible to perform univariate and multivariate analyses with sufficient power of the test. The study design we adopted allows us to realistically assess the outcomes of patients qualified for the PCC and UCC insertion procedure, given the low risk of miscarriage while awaiting culture results or antibiotic therapy. The authors are aware that there may be a small group of patients who, because of prolonged antibiotic therapy, enter a period of pregnancy in which a cervical cerclage can no longer be placed, but this does not mean that they do not benefit from preoperative management alone.