Recurrent Pregnancy Loss and Uterine Anomalies: A Complete Guide for Patients in Chennai

Recurrent pregnancy loss (RPL) is defined by ESHRE as the loss of two or more pregnancies, and affects around 1–2% of couples (doi.org/10.1093/hropen/hoad002). RCOG's Green-top Guideline No. 17 defines recurrent miscarriage as three or more first-trimester miscarriages but encourages evaluation after two. RPL carries a distinct set of causes that differ from isolated pregnancy loss.

Clinicians distinguish primary RPL, where a woman has never carried a pregnancy beyond 24 weeks, from secondary RPL, where losses follow at least one successful pregnancy. Both forms share the same range of underlying causes: genetic, anatomical, endocrine, autoimmune, thrombophilic, and environmental factors. Uterine anomalies sit firmly in the anatomical category and are among the most actionable causes once identified.

Because the emotional burden of repeated loss is profound, a structured investigation after two miscarriages, rather than waiting for three, is now widely recommended. Understanding whether a structural uterine problem is contributing is a critical first step, and it is one that can be answered quickly with modern imaging. Women experiencing recurrent miscarriages deserve a thorough, compassionate workup rather than reassurance alone.

Congenital uterine anomalies arise from embryological defects in the formation, fusion, or septal resorption of the Müllerian ducts, the paired structures that develop into the uterus, fallopian tubes, and upper vagina. Major classification systems include the older AFS/ASRM scheme and the more detailed ESHRE/ESGE classification (doi.org/10.1093/humrep/det098), which incorporates quantifiable imaging criteria to improve reproducibility.

The ESHRE/ESGE system groups anomalies from Class U0 (normal uterus) through to Class U6 (unclassified), with each class defined by measurable thresholds on 3D ultrasound or MRI. This precision matters clinically because the distinction between, say, a septate uterus (Class U2) and a bicornuate uterus (Class U3) directly determines whether surgery is appropriate.

Prevalence estimates vary by population and diagnostic method, but a 2011 systematic review found uterine anomalies in about 5.5% of unselected women, 8.0% of infertile women and 13.3% of women with a history of miscarriage (doi.org/10.1093/humupd/dmr028). Identifying the specific anomaly type, not just confirming that one exists, is therefore essential before any management decision is made.

• Anomaly Type: Septate uterus · ESHRE/ESGE Class: U2 · Key Feature: Internal septum; normal external contour · RPL Relevance: Strongly associated with RPL
• Anomaly Type: Bicornuate uterus · ESHRE/ESGE Class: U3 · Key Feature: External fundal indentation >50% of uterine wall thickness; two horns · RPL Relevance: Associated with preterm birth and malpresentation; evidence for first-trimester RPL is mixed
• Anomaly Type: Arcuate uterus · ESHRE/ESGE Class: Not a separate class (minor deformity, U1 'other') · Key Feature: Broad cavity with a mild, smooth internal indentation (<50% of wall thickness) · RPL Relevance: Generally considered benign; unclear RPL significance
• Anomaly Type: Didelphic uterus · ESHRE/ESGE Class: U3b (complete bicorporeal, double cervix) · Key Feature: Complete duplication of uterus and cervix · RPL Relevance: Associated with preterm birth; surgery rarely indicated
• Anomaly Type: Unicornuate uterus · ESHRE/ESGE Class: U4 · Key Feature: Single horn from one Müllerian duct · RPL Relevance: Associated with miscarriage and preterm birth

A septate uterus is the most common uterine anomaly among women with recurrent pregnancy loss. It results from failure of resorption of the uterovaginal septum after the Müllerian ducts have fused, leaving a fibrous or muscular partition inside the uterine cavity. This septum has reduced vascularity and defective endometrium, making it a poor site for embryo implantation and placentation, a finding detailed in a study published via doi.org/10.14260/jemds/2015/644.

When an embryo implants on or near the septum, the inadequate blood supply impairs decidualisation, the transformation of the endometrium that supports early pregnancy. The result is a higher rate of first-trimester miscarriage compared with women who have a normal uterine cavity. The septum can also reduce the functional volume of the cavity, which may contribute to second-trimester loss and preterm birth as the pregnancy grows.

Importantly, a septate uterus looks normal from the outside; the external uterine contour is intact. This is why imaging that shows only the cavity, such as a standard 2D ultrasound or hysterosalpingography (HSG), can miss the diagnosis or misclassify it as a bicornuate uterus. Accurate classification requires simultaneous visualisation of both the internal cavity and the external fundal contour.

A bicornuate uterus results from incomplete fusion of the Müllerian ducts and is defined under the ESHRE/ESGE system by an external fundal indentation of more than 50% of the uterine wall thickness, giving the uterus a heart-shaped appearance with two distinct horns. Unlike the septate uterus, the tissue dividing the two cavities in a bicornuate uterus is composed of myometrium rather than a fibrous septum, and the external contour is abnormal, a distinction that can be confirmed by 3D ultrasound or laparoscopy, as described in doi.org/10.1016/S0015-0282(03)01169-5.

The reproductive implications of a bicornuate uterus differ meaningfully from those of a septate uterus. It is associated with preterm delivery, fetal malpresentation, and intrauterine growth restriction, and a meta-analysis also found a higher risk of first-trimester miscarriage (doi.org/10.3390/jcm10204797). This distinction matters because the surgical approach for each anomaly is entirely different, and operating on a bicornuate uterus when a septate uterus was the intended target, or vice versa, carries real risk.

Differentiating the two anomalies is one of the most clinically important tasks in the workup of recurrent pregnancy loss uterine anomalies. A divided uterine cavity seen on HSG is highly suggestive of a septate uterus rather than a bicornuate uterus in the RPL population, but definitive classification requires 3D ultrasound or, in ambiguous cases, combined hysteroscopy and laparoscopy.

An arcuate uterus is a mild variant characterised by a broad uterine cavity with a smooth internal indentation whose depth is less than half the uterine wall thickness. The ESHRE/ESGE classification does not list arcuate uterus as a separate class; minor deformities of this kind are grouped under dysmorphic uterus (Class U1, 'other') (doi.org/10.1093/humrep/det098). It is generally considered a normal variant or a minor anomaly, and its significance in recurrent pregnancy loss remains unclear.

Most reproductive medicine guidelines do not recommend surgical intervention for an arcuate uterus in the absence of other contributing factors. Women found to have this variant during RPL investigations should be reassured that it is unlikely to be the primary cause of their losses, and the workup should continue to identify other aetiologies such as chromosomal, thrombophilic, or endocrine factors.

Other less common anomalies, including unicornuate uterus and uterine didelphys, are associated with preterm birth and malpresentation more than with first-trimester RPL. Surgical correction for these variants carries significant perioperative risk and is not routinely recommended outside highly specialised centres or clinical trials.

Recurrent pregnancy loss uterine anomalies cause miscarriage through several overlapping mechanisms, all rooted in a structurally and functionally impaired uterine environment. A systematic review and meta-analysis published at doi.org/10.3390/jcm10204797 notes that the mechanisms are not fully understood, but discusses poor endometrial vascularity, defective decidualisation, altered uterine contractility, and reduced cavity space as likely contributors.

Poor vascularity in a uterine septum means that a developing embryo implanting on septal tissue receives inadequate nutrients and oxygen during the critical window of early placentation. Defective decidualisation, the process by which the endometrium remodels to support pregnancy, further undermines the embryo's ability to establish a stable connection with the uterine wall.

Reduced uterine cavity size, particularly relevant in a septate or bicornuate uterus, limits the space available for fetal growth and increases the risk of preterm labour, fetal malpresentation, and placental complications in pregnancies that do progress beyond the first trimester. Understanding these mechanisms helps explain why treatment is not one-size-fits-all: the anomaly type, its severity, and the individual patient's reproductive history all shape the management plan.

The investigation of recurrent pregnancy loss uterine anomalies begins with imaging, and the choice of modality determines diagnostic accuracy. According to RCOG's Green-top Guideline No. 17, women with recurrent miscarriage should be offered assessment for congenital uterine anomalies, ideally with 3D ultrasound. The RCOG Scientific Impact Paper on uterine anomalies (doi.org/10.1111/1471-0528.18054) adds that MRI, laparoscopy or hysteroscopy are used when a complex anomaly is suspected.

A stepwise approach (starting with 3D ultrasound, escalating to MRI or combined hysteroscopy and laparoscopy where needed) balances diagnostic accuracy against invasiveness and cost. Importantly, investigation should ideally begin after two miscarriages rather than waiting for three, because, in one study, acquired uterine anomalies (such as fibroids, polyps and adhesions) were found just as often in women with two losses as in women with three or more.

For women already undergoing fertility treatment, ovarian reserve testing and uterine assessment are often performed together as part of a comprehensive pre-treatment workup, ensuring that both ovarian and uterine factors are addressed before proceeding to IVF or other assisted conception.

3D transvaginal ultrasound is the single most important non-invasive tool for diagnosing recurrent pregnancy loss uterine anomalies. It generates a coronal plane of the uterus, a view not available with standard 2D ultrasound, that allows simultaneous assessment of the uterine cavity shape and the external fundal contour, which is precisely the information needed to distinguish a septate from a bicornuate uterus (doi.org/10.1111/1471-0528.18054). In a cohort of 442 women with recurrent pregnancy loss screened by 3D transvaginal ultrasound, a partial septate uterus was found in 7% to 14%, depending on the criteria used (doi.org/10.1093/humrep/deae148).

In practice, 3D ultrasound can measure the depth and width of an internal indentation, the fundal cleft depth, and the overall uterine volume, all of which feed into the ESHRE/ESGE classification criteria. Its sensitivity and specificity for detecting major uterine anomalies are high, making it the appropriate starting point before any invasive investigation is considered.

The availability of high-resolution 3D ultrasound at a dedicated fertility centre is therefore a meaningful clinical advantage for women with recurrent pregnancy loss in Chennai. Early, accurate classification avoids unnecessary surgery for women with arcuate or bicornuate uteri while ensuring that women with a true septate uterus are offered the appropriate intervention promptly.

Hysterosalpingography (HSG), an X-ray procedure in which contrast dye is injected through the cervix to outline the uterine cavity and fallopian tubes, remains a useful screening tool but has a critical limitation: it shows only the internal cavity and cannot visualise the external uterine contour. A divided cavity on HSG in a woman with recurrent pregnancy loss is highly suggestive of a septate uterus, but the diagnosis cannot be confirmed without external contour assessment (doi.org/10.1016/S0015-0282(03)01169-5).

Hysteroscopy, direct visualisation of the uterine cavity through a thin telescope passed through the cervix, is both diagnostic and potentially therapeutic. When combined with laparoscopy (which visualises the external uterine surface), it remains the gold standard for definitively differentiating a septate from a bicornuate uterus. MRI offers superior soft-tissue contrast and is particularly valuable when coexisting pathology such as endometriosis or fibroids complicates the picture.

The decision to proceed to invasive investigation is made on an individual basis. For most women, 3D ultrasound will provide sufficient information. Hysteroscopy and laparoscopy are reserved for cases where imaging is ambiguous, where treatment is planned, or where additional pelvic pathology needs to be excluded.

Management of recurrent pregnancy loss uterine anomalies depends entirely on the anomaly type, its severity, and the individual patient's history. Surgical septum resection by hysteroscopic metroplasty is the primary intervention for septate uterus, while surgery for bicornuate and other anomalies is rarely recommended due to limited evidence of benefit and higher perioperative risk, as outlined in doi.org/10.3109/01443615.2014.936839.

Beyond uterine surgery, a comprehensive RPL management plan addresses all identified contributing factors simultaneously. Endocrine disorders such as thyroid dysfunction or uncontrolled PCOS are corrected; antiphospholipid syndrome is treated with anticoagulation; and psychological support is offered as standard. Medical therapies for uterine factors specifically have limited high-quality evidence, but RCOG advises that women with unexplained recurrent miscarriage be offered supportive care, ideally in a dedicated recurrent miscarriage clinic (RCOG Green-top Guideline No. 17).

For couples where uterine anomalies coexist with other infertility factors, such as sperm DNA fragmentation or unexplained infertility, a multidisciplinary approach that addresses all factors before or alongside uterine treatment gives the best chance of a successful pregnancy.

Hysteroscopic metroplasty, the surgical removal of a uterine septum using a hysteroscope passed through the cervix, is the preferred procedure for restoring normal uterine cavity anatomy in women with a septate uterus and recurrent pregnancy loss. It is a minimally invasive day-case procedure performed under general or regional anaesthesia, with no abdominal incisions required.

Observational data are mixed. In a prospective study of 170 women with two or more miscarriages and a septate or bicornuate uterus, the live birth rate at the first pregnancy after diagnosis tended to be higher with surgery than without in women with a septate uterus (81.3% versus 61.5%) (doi.org/10.3109/01443615.2014.936839). In a retrospective cohort of 72 women with a septate uterus, live birth occurred in 52.2% after resection and 34.6% with expectant management, a difference that was not statistically significant (doi.org/10.1016/j.jmig.2023.07.012). The TRUST trial, an international multicentre RCT of 80 women with a septate uterus, found live birth within 12 months in 31% after septum resection and 35% with expectant management, so no benefit (doi.org/10.1093/humrep/deab037). This has led to genuine debate in the reproductive medicine community about which patients benefit most.

RCOG guidance says resection of a uterine septum should be considered for women with recurrent miscarriage, ideally within an audit or research setting, while the ESHRE 2022 guideline says its benefit should be evaluated in surgical trials. It can be a reasonable option for women with a clearly defined septate uterus and recurrent pregnancy loss, provided they receive thorough informed consent about the uncertainty in the evidence. The decision should be individualised, taking into account septum size, number of prior losses, patient age, and the presence of other contributing factors. Your consultant at Jananam will discuss the available evidence transparently so that you can make an informed choice.

Abdominal metroplasty, the open surgical unification of a bicornuate or didelphic uterus, carries significant perioperative risks including haemorrhage, adhesion formation, and the need for caesarean section in all future pregnancies. According to the RCOG Scientific Impact Paper on congenital uterine anomalies (doi.org/10.1111/1471-0528.18054), surgical treatment for anomalies other than a septate uterus is not usually recommended, because the risks outweigh the potential benefits and evidence of benefit is lacking.

For most women with a bicornuate uterus and recurrent pregnancy loss, the recommended approach is expectant management with close obstetric surveillance in subsequent pregnancies, combined with investigation and treatment of any coexisting RPL causes. Preterm birth prevention strategies, including cervical length monitoring and progesterone supplementation where indicated, are more relevant for bicornuate uterus than uterine surgery.

Women with a unicornuate uterus face a different set of challenges, including a higher risk of ectopic pregnancy and preterm birth, but again surgical correction of the uterine anatomy itself offers little proven benefit. The focus shifts to optimising the conditions for pregnancy and managing obstetric risk proactively.

Prognosis after treatment for recurrent pregnancy loss uterine anomalies is most favourable for women with a septate uterus who undergo hysteroscopic resection. Some observational studies report a higher live birth rate after resection, but the differences were not statistically significant, and the TRUST randomised trial found no improvement (doi.org/10.3109/01443615.2014.936839).

Several factors influence individual outcomes: the size of the septum, patient age, ovarian reserve, the number of prior losses, and whether other RPL causes have been identified and treated.

It is important to frame outcomes honestly: fertility treatment outcomes vary, and multiple cycles or interventions are often needed. The goal of treatment is to improve the probability of a successful pregnancy, not to guarantee one. Your consultant will discuss realistic expectations based on your specific clinical picture, including whether pre-implantation genetic testing alongside IVF might add further benefit in your case.

Recurrent pregnancy loss uterine anomalies are not a rare problem in South India. A study of women with RPL in the region, published at doi.org/10.14260/jemds/2015/644, found a 15.8% prevalence of congenital uterine anomalies in this population, with septate uterus as the most common finding. This figure underscores the importance of accessible, high-quality diagnostic imaging for women in Chennai who have experienced repeated pregnancy loss.

Jananam Fertility Centre in Neelankarai, Chennai, is a single-speciality clinic focused exclusively on infertility and reproductive medicine. The team brings over two decades of combined experience in reproductive medicine, and the clinic's Certified Cleanroom Lab is particularly relevant for women who proceed to IVF after uterine correction, maintaining optimal embryo culture conditions that matter most in complex cases. The availability of 3D transvaginal ultrasound at Jananam means that the critical first step of accurate uterine anomaly classification can be completed without referral elsewhere.

For couples in Chennai navigating the distressing experience of recurrent pregnancy loss, having a dedicated team that can investigate, diagnose, and manage both uterine and non-uterine causes under one roof, from ovarian reserve testing to ICSI and pre-implantation genetic testing, makes a meaningful difference to the care journey.