A “cluster” of ten uterine anomalies observed in a single center over a short period of 4 weeks: a case series

Uterine malformations are as result of agenesis, hypoplasia, abnormal fusion, or resorption of Müllerian ducts. The causes of uterine malformations are multifactorial. Some of them are ionizing radiations, viral infections, drug induced and genetic mutation involving BCL2 gene. The incidence of Müllerian anomaly is 0.2%–3.8% in fertile women and 3.5%–6.3% in infertile women. In one study, it was 4.4%, with septate uterus leading the anomalies [1]. Women with uterine malformations who are asymptomatic and are not operated remain undiagnosed. Some of the anomalies in these women may be diagnosed during imaging, Lower segment cesarean section (LSCS), laparotomy, or laparoscopy, as in our last case (Table 1). Müllerian duct anomalies are classified according to the 1988 American Fertility Society classification. We mention here the number of cases in our series in each category of the classification.

The number of cases in each group is as follows. Class I: agenesis/hypoplasia (nil); class II: unicornuate (two cases); class III: didelphys (two cases); class IV: bicornuate (four cases); class V: septate (one case); class VI: arcuate (one case); class VII: drug induced (nil).

As per our thorough literature search, most of these anomalies have been reported as isolated case reports [2], while case series mention a very small number of cases with anomalies [3]. Our series of ten cases presenting in a span of just one  month is like a “cluster”. In this cluster, we were able to identify almost all the uterine malformations. Eight out of the ten cases were diagnosed intraoperatively during LSCS/laparoscopy. In epidemiology, a cluster is defined as an aggregation of cases of a disease or a health-related condition, such as a cancer or birth defect, closely grouped in time and place. Here, we could not find any geographic or demographic similarities among this cluster of women with uterine malformations. We therefore call it a cluster, although it does not fit the exact definition. Yet in our practice, we see clustering of similar types of cases especially in the labor room, which cannot be explained by anything but chance occurrence. But, by attributing it to chance occurrence, are we missing something that needs to be understood or discovered? Appropriate studies need to be planned and carried out to determine the cause of such occurrence of events in clusters, which at present appear to be just due to chance.

A total of ten cases admitted to the Department of Obstetrics and Gynaecology during November and December 2020 in a tertiary care hospital in South India had various uterine malformations. For all these cases written informed consent for the specific intervention of surgery and anesthesia was taken. Consent for photographing/recording of events and for publications (if done) was also taken, and patients consented to the same. Institutional review board approval of the Medical Research Unit of our institute (Karnataka Institute Of Medical Sciences Hubballi) was taken. Eight cases admitted near term underwent LSCS . One case with 9 weeks of gestation underwent manual vacuum aspiration (MVA). One case was admitted for laparoscopic sterilization. The demographic and clinical data are presented in Table 1. All women were of Kannadiga ethnicity and in the age range of 19–35 years. They were from places nearby to our institute within a range of approximately 250 km.

The mean age was 24.7 years (median 23.5 years, range 19–35 years). Eight cases presented in the third trimester. One case presented at 9 weeks for MVA, and another case was admitted for laparoscopic sterilization. Median gestational age was 38 weeks, ranging from 9 to 40 weeks. Four of these cases had history of spontaneous abortion in first trimester. There is no history of interventions for uterine anomaly correction before pregnancy in any of these cases. None of these cases had past history of known uterine anomalies (they were undiagnosed/ or intraoperative history not available). None had any past history of diabetes, hypertension, endocrine disorders, or Anti Phospholipid Antibody Syndrome (APLA) syndrome. One of the women had undergone cardiac surgery in the past. Family history of any other congenital anomalies was absent. There was no other significant family history. Menstrual history was regular and uneventful in all cases. The indications for LSCS in these cases were antepartum eclampsia, breech presentation, previous LSCS with threatened scar rupture, fetal growth retardation, oligohydramnios, cephalopelvic disproportion (CPD), footling presentation, and preterm breech as shown in the table.

Antenatal diagnosis of uterine malformation by USG was available in only two cases. One case showed single live intrauterine gestation (SLIUG) of 7 weeks + 6 days with bicornuate uterus (Table 1, case 6) while another case (Table 1, case 3) showed SLIUG of 9 weeks with uterine didelphys. Per vaginal examination findings of bicornuate uterus (case 6) were appreciated only after first trimester ultrasonography diagnoses was available. The rest of the cases were diagnosed intraoperatively during LSCS (seven cases) and one during laparoscopic sterilization. The significant antenatal details of all the cases is summarized in the table. Figures 1 and 2 show photographs of the cases. All these cases did not have any problems during their stay in the hospital. Eight cases who delivered had healthy babies without any obvious congenital anomalies.

Müllerian ducts are the primordial anlage of the female reproductive tract that differentiates to form the fallopian tubes, body of uterus, cervix, and the upper part of vagina. Müllerian duct anomalies may lead to adverse obstetric outcome.

The mean age of presentation is typically in adolescence for girls with genital tract outflow obstructive anomalies. In contrast, the mean age of presentation in our series as obstetric cases is 24.7 years, which is comparable to studies [4], showing slightly higher age, which can be explained by the few who suffered poor obstetric history. Due to the close embryologic relationship between paramesonephric and mesonephric ducts, failure of development in both of them may result in the coexistence of congenital uterine and renal anomalies. Congenital ipsilateral renal agenesis was reported in literature in 16–38% of women with unicornuate uterus. None of our cases had associated renal congenital anomalies. USG helps early identification of uterine anomalies. One of the previous case series mentioned that four out of seven cases were diagnosed by USG [4]. In contrast, we had only two cases with USG diagnosis of uterine anomalies in the antenatal period. Intraoperative diagnosis during cesarean section was reported in three out of seven cases [4]. Similarly, in the present study, eight out of ten cases were diagnosed during caesarean section or laparoscopic sterilization. In our study, most of the cases were diagnosed intraoperatively and not antenatally could be explained due to difficulty or inability to diagnose antenatally.

As described in many studies, uterine anomalies result in adverse obstetric outcomes including early pregnancy loss, malpresentation, and preterm labor. These adverse effects are related to specific types of uterine anomalies. Among these adverse outcomes, malpresentation (predominantly breech presentation) are common and lead to cesarean delivery. It has been reported that rates of cesarean delivery are increased in cases of uterine anomalies. This finding is similar to our case series, in which 80% of cases were diagnosed intraoperatively during LSCS.

Such clinical presentation of uterine anomalies as a cluster and within a short period has not been described previously. Our case series included almost all uterine anomalies in a significant number, presented in a short span of time like a cluster at a single institute. This is an unusual occurrence. This might be a rare incidental finding worth mentioning as a rare cluster of uterine anomalies. We need to devise studies to study the cause of such clustering of cases that appear like chance occurrences.

The present case series describes almost all types of uterine anomalies within a very short span of four weeks like a cluster (whereas it usually takes more time to accumulate such a number of cases) [4], and most of them were diagnosed intraoperatively. Diagnosis of uterine malformations is usually missed, but they should be considered in cases of poor obstetric history or women presenting with infertility. Quite a number of times, we have found noninfectious events of a particular nature occurring repeatedly over a period of time in our clinical practice, which we attribute to chance occurrence. We need to identify such clustering and formulate studies to determine the reason for such events in our clinical practice. This would be useful if the events are life threatening or need prior preparation.