Can risk factors, clinical history and symptoms be used to predict risk of ectopic pregnancy in women attending an early pregnancy assessment unit?

OBJECTIVE

To examine whether risk factors and symptoms may be used to predict the likelihood of ectopic pregnancy (EP) in women attending early pregnancy assessment units in the UK.

METHODS

This was an observational cohort study of pregnant women under 12 weeks' gestation who were recruited from three London university hospitals between August 2012 and April 2013. One hospital continued recruitment between January and June 2015. A standardized information sheet incorporating patient demographics, medical history and symptoms was completed by patients and confirmed by examining clinicians. The outcome measure was final pregnancy location.

RESULTS

There were 1320 eligible patients included in the analysis, with a total of 72 EPs (rate of 6%). Pelvic pain and diarrhea > three times in the previous 24 h were independent symptoms that increased the risk of EP, with relative risks of 2.4 (95% CI, 1.4-4.0; P = 0.002) and 2.2 (95% CI, 1.08-4.5; P = 0.03), respectively. The only other independent marker of risk of EP was duration of vaginal bleeding; the risk of EP increased by 20% (95% CI, 14%-27%) for every 1-day increment in duration (P < 0.001). A logistic regression model incorporating these factors demonstrated an area under the receiver-operating characteristics curve of 0.73 (95% CI, 0.67-0.79). The prevalence of EP was low when there was no pelvic pain, no diarrhea and the duration of bleeding was ≤ 3 days, with an EP rate of 2% (6/391). In the presence of a single risk factor, the EP rate increased to 5% (29/631) when only pelvic pain was present, 8% (1/12) when only diarrhea > three times in the previous 24 h was reported and 9% (9/103) when there was only vaginal bleeding with a duration > 3 days. Women with pelvic pain and vaginal bleeding of any severity for > 3 days had a high EP rate of 16% (23/146). In the nine women who also reported diarrhea > three times in the previous 24 h, two had EP.

CONCLUSIONS

Only the presence of pelvic pain, diarrhea > three times in the previous 24 h and duration of bleeding were symptoms that significantly increased the risk for EP in women attending early pregnancy assessment units. Risk factors and symptoms alone could not be used to predict reliably an EP. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Managing pregnancy of unknown location based on initial serum progesterone and serial serum hCG levels: development and validation of a two-step triage protocol

OBJECTIVES

A uniform rationalized management protocol for pregnancies of unknown location (PUL) is lacking. We developed a two-step triage protocol to select PUL at high risk of ectopic pregnancy (EP), based on serum progesterone level at presentation (step 1) and the serum human chorionic gonadotropin (hCG) ratio, defined as the ratio of hCG at 48 h to hCG at presentation (step 2).

METHODS

This was a cohort study of 2753 PUL (301 EP), involving a secondary analysis of prospectively and consecutively collected PUL data from two London-based university teaching hospitals. Using a chronological split we used 1449 PUL for development and 1304 for validation. We aimed to assign PUL as low risk with high confidence (high negative predictive value (NPV)) while classifying most EP as high risk (high sensitivity). The first triage step assigned PUL as low risk using a threshold of serum progesterone at presentation. The remaining PUL were triaged using a novel logistic regression risk model based on hCG ratio and initial serum progesterone (second step), defining low risk as an estimated EP risk of < 5%.

RESULTS

On validation, initial serum progesterone ≤ 2 nmol/L (step 1) classified 16.1% PUL as low risk. Second-step classification with the risk model selected an additional 46.0% of all PUL as low risk. Overall, the two-step protocol classified 62.1% of PUL as low risk, with an NPV of 98.6% and a sensitivity of 92.0%. When the risk model was used in isolation (i.e. without the first step), 60.5% of PUL were classified as low risk with 99.1% NPV and 94.9% sensitivity.

CONCLUSION

PUL can be classified efficiently into being either high or low risk for complications using a two-step protocol involving initial progesterone and hCG levels and the hCG ratio. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Systematic approach to sonographic evaluation of the pelvis in women with suspected endometriosis, including terms, definitions and measurements: a consensus opinion from the International Deep Endometriosis Analysis (IDEA) group

The IDEA (International Deep Endometriosis Analysis group) statement is a consensus opinion on terms, definitions and measurements that may be used to describe the sonographic features of the different phenotypes of endometriosis. Currently, it is difficult to compare results between published studies because authors use different terms when describing the same structures and anatomical locations. We hope that the terms and definitions suggested herein will be adopted in centers around the world. This would result in consistent use of nomenclature when describing the ultrasound location and extent of endometriosis. We believe that the standardization of terminology will allow meaningful comparisons between future studies in women with an ultrasound diagnosis of endometriosis and should facilitate multicenter research. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Evaluating the risk of ovarian cancer before surgery using the ADNEX model: a multicentre external validation study

BACKGROUND

The International Ovarian Tumour Analysis (IOTA) group have developed the ADNEX (The Assessment of Different NEoplasias in the adneXa) model to predict the risk that an ovarian mass is benign, borderline, stage I, stages II-IV or metastatic. We aimed to externally validate the ADNEX model in the hands of examiners with varied training and experience.

METHODS

This was a multicentre cross-sectional cohort study for diagnostic accuracy. Patients were recruited from three cancer centres in Europe. Patients who underwent transvaginal ultrasonography and had a histological diagnosis of surgically removed tissue were included. The diagnostic performance of the ADNEX model with and without the use of CA125 as a predictor was calculated.

RESULTS

Data from 610 women were analysed. The overall prevalence of malignancy was 30%. The area under the receiver operator curve (AUC) for the ADNEX diagnostic performance to differentiate between benign and malignant masses was 0.937 (95% CI: 0.915-0.954) when CA125 was included, and 0.925 (95% CI: 0.902-0.943) when CA125 was excluded. The calibration plots suggest good correspondence between the total predicted risk of malignancy and the observed proportion of malignancies. The model showed good discrimination between the different subtypes.

CONCLUSIONS

The performance of the ADNEX model retains its performance on external validation in the hands of ultrasound examiners with varied training and experience.

The clinical performance of the M4 decision support model to triage women with a pregnancy of unknown location as at low or high risk of complications

STUDY QUESTION

What are the adverse outcomes associated with using the M4 model in everyday clinical practice for women with pregnancy of unknown location (PUL)?

SUMMARY ANSWER

There were 17/835 (2.0%) adverse events and no serious adverse events associated with the performance of the M4 model in clinical practice.

WHAT IS KNOWN ALREADY

The M4 model has previously been shown to stratify women classified as a PUL as at low or high risk of complications with a good level of test performance. The triage performance of the M4 model is better than single measurements of serum progesterone or the hCG ratio (serum hCG at 48 h/hCG at presentation).

STUDY DESIGN, SIZE, DURATION

A prospective multi-centre cohort study of 1022 women with a PUL carried out between August 2012 and December 2013 across 2 university teaching hospitals and 1 district general hospital.

PARTICIPANTS/MATERIALS, SETTING, METHODS

All women presenting with a PUL to the early pregnancy units of the three hospitals were recruited. The final outcome for PUL was either a failed PUL (FPUL), intrauterine pregnancy (IUP) or ectopic pregnancy (EP) (including persistent PUL (PPUL)), with EP and PPUL considered high-risk PUL. Their hCG results at 0 and 48 h were entered into the M4 model algorithm. If the risk of EP was ≥5%, the PUL was predicted to be high-risk and the participant was asked to re-attend 48 h later for a repeat hCG and transvaginal ultrasound scan by a senior clinician. If the PUL was classified as 'low risk, likely failed PUL', the participant was asked to perform a urinary pregnancy test 2 weeks later. If the PUL was classified as 'low risk, likely intrauterine', the participant was scheduled for a repeat scan in 1 week. Deviations from the management protocol were recorded as either an 'unscheduled visit (participant reason)', 'unscheduled visit (clinician reason)' or 'differences in timing (blood test/ultrasound)'. Adverse events were assessed using definitions outlined in the UK Good Clinical Practice Guidelines' document.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 835 (82%) women classified as a PUL were managed according to the M4 model (9 met the exclusion criteria, 69 were lost to follow-up, 109 had no hCG result at 48 h). Of these, 443 (53%) had a final outcome of FPUL, 298 (36%) an IUP and 94 (11%) an EP. The M4 model predicted 70% (585/835) PUL as low risk, of which 568 (97%) were confirmed as FPUL or IUP. Of the 17 EP and PPUL misclassified as low risk, 5 had expectant management, 7 medical management with methotrexate and 5 surgical intervention.Nineteen PUL had an unscheduled visit (participant reason), 38 PUL had an unscheduled visit (clinician reason) and 68 PUL had deviations from protocol due to a difference in timing (blood test/ultrasound).Adverse events were reported in 26 PUL and 1 participant had a serious adverse event. A total of 17/26 (65%) adverse events were misclassifications of a high risk PUL as low risk by the M4 model, while 5/26 (19%) adverse events were related to incorrect clinical decisions. Four of the 26 adverse events (15%) were secondary to unscheduled admissions for pain/bleeding. The serious adverse event was due to an incorrect clinical decision.

LIMITATIONS, REASONS FOR CAUTION

A limitation of the study was that 69/1022 (7%) of PUL were lost to follow-up. A 48 h hCG level was missing for 109/1022 (11%) participants.

WIDER IMPLICATIONS OF THE FINDINGS

The low number of adverse events (2.0%) suggests that expectant management of PUL using the M4 prediction model is safe. The model is an effective way of triaging women with a PUL as being at high- and low-risk of complications and rationalizing follow-up. The multi-centre design of the study is more likely to make the performance of the M4 model generalizable in other populations.

STUDY FUNDING/COMPETING INTERESTS

None.

TRIAL REGISTRATION NUMBER

Not applicable.

Terms, definitions and measurements to describe sonographic features of myometrium and uterine masses: a consensus opinion from the Morphological Uterus Sonographic Assessment (MUSA) group

The MUSA (Morphological Uterus Sonographic Assessment) statement is a consensus statement on terms, definitions and measurements that may be used to describe and report the sonographic features of the myometrium using gray-scale sonography, color/power Doppler and three-dimensional ultrasound imaging. The terms and definitions described may form the basis for prospective studies to predict the risk of different myometrial pathologies, based on their ultrasound appearance, and thus should be relevant for the clinician in daily practice and for clinical research. The sonographic features and use of terminology for describing the two most common myometrial lesions (fibroids and adenomyosis) and uterine smooth muscle tumors are presented.

Accuracy of ultrasonography performed by examiners with varied training and experience in predicting specific pathology of adnexal masses

OBJECTIVES

To assess the diagnostic performance of subjective assessment by Level II ultrasound examiners in predicting the specific histology of adnexal masses.

METHODS

The women included in this prospective multicenter cross-sectional study were older than 16 years of age and had at least one adnexal mass. They underwent transvaginal sonography (TVS) performed by Level II examiners, all of whom were familiar with the International Ovarian Tumor Analysis (IOTA) group definitions of ultrasound features of ovarian masses. The final outcome was histology. Specific diagnoses were categorized into 16 groups. Agreement between subjective assessment and final histology was measured using unweighted kappa coefficients. Sensitivities and specificities were obtained for subjective assessment.

RESULTS

Of the 1279 women who underwent TVS, 313 were included in the final analysis. Overall agreement (16 × 16 table) between subjective assessment and histology was moderate, with a Cohen's kappa coefficient of 0.59 (95% CI, 0.53-0.65). The specificity of subjective assessment ranged between 91% and 100% for all histological subgroups. Highest sensitivities were achieved in the diagnosis of simple cysts (100% (95% CI, 61-100%)), hydrosalpinges (100% (95% CI, 34-100%)), mature teratomas (88% (95% CI, 74-96%)), endometriomas (75% (95% CI, 61-85%)), ovarian fibromas (88% (95% CI, 47-100%)), tubo-ovarian abscesses (88% (95% CI, 47-100%)) and serous cystadenocarcinomas (82% (95% CI, 66-93%)). Serous cystadenomas were misdiagnosed most commonly (40.5%). The sensitivity of subjective assessment in diagnosing adnexal torsion was 54% (95% CI, 25-81%); the 17 confirmed and/or suspected cases of adnexal torsion were not included in the 313 cases examined and analyzed for diagnostic performance.

CONCLUSION

Overall, subjective assessment by Level II examiners was good for the detection of simple cysts, endometriomas, mature teratomas, hydrosalpinges, fibroma, tubo-ovarian abscess and serous cystadenocarcinomas.

Automated characterisation of ultrasound images of ovarian tumours: the diagnostic accuracy of a support vector machine and image processing with a local binary pattern operator

INTRODUCTION

Preoperative characterisation of ovarian masses into benign or malignant is of paramount importance to optimise patient management.

OBJECTIVES

In this study, we developed and validated a computerised model to characterise ovarian masses as benign or malignant.

MATERIALS AND METHODS

Transvaginal 2D B mode static ultrasound images of 187 ovarian masses with known histological diagnosis were included. Images were first pre-processed and enhanced, and Local Binary Pattern Histograms were then extracted from 2 × 2 blocks of each image. A Support Vector Machine (SVM) was trained using stratified cross validation with randomised sampling. The process was repeated 15 times and in each round 100 images were randomly selected.

RESULTS

The SVM classified the original non-treated static images as benign or malignant masses with an average accuracy of 0.62 (95% CI: 0.59-0.65). This performance significantly improved to an average accuracy of 0.77 (95% CI: 0.75-0.79) when images were pre-processed, enhanced and treated with a Local Binary Pattern operator (mean difference 0.15: 95% 0.11-0.19, p < 0.0001, two-tailed t test).

CONCLUSION

We have shown that an SVM can classify static 2D B mode ultrasound images of ovarian masses into benign and malignant categories. The accuracy improves if texture related LBP features extracted from the images are considered.

Intra-cavitary uterine pathology in women with abnormal uterine bleeding: a prospective study of 1220 women

OBJECTIVES

Our primary aim was to assess how patients' characteristics, bleeding pattern, sonographic endometrial thickness (ET) and additional features at unenhanced ultrasound examination (UTVS) and at fluid instillation sonography (FIS) contribute to the diagnosis of intracavitary uterine pathology in women presenting with abnormal uterine bleeding (AUB). We further aimed to report the prevalence of pathology in women presenting with AUB.

METHODS

1220 consecutive women presenting with AUB underwent UTVS, colour Doppler imaging (CDI) and FIS. Most women (n = 1042) had histological diagnosis.

RESULTS

Mean age was 50 years and 37% were postmenopausal. Of 1220 women 54% were normal, polyps were diagnosed in 26%, intracavitary fibroids in 11%, hyperplasia without atypia in 4% and cancer in 3%. All cancers were diagnosed in postmenopausal (7%) or perimenopausal (1%) women. ET had a low predictive value in premenopausal women (LR+ and LR- of 1.34 and 0.74, respectively), while FIS had a LR+ and LR- of 6.20 and 0.24, respectively. After menopause, ET outperformed all patient characteristics for the prediction of endometrial pathology (LR+ and LR- of 3.13 and 0.24). The corresponding LR+ and LR- were 10.85 and 0.71 for CDI and 8.23 and 0.26 for FIS.

CONCLUSION

About half of the women presenting to a bleeding clinic will have pathology. In premenopausal women, benign lesions are often the cause of AUB. For the prediction of intracavitary pathology ET is of little value in premenopausal women. CDI and FIS substantially improve the diagnostic accuracy.

Use of a pocket-sized ultrasound machine (PUM) for routine examinations in the third trimester of pregnancy

OBJECTIVES

To evaluate the application of a pocket-sized ultrasound machine (PUM) in a routine antenatal third-trimester scan compared with a high-specification ultrasound machine (HSUM).

METHODS

This was an observational cohort study of 53 unselected women who came for their routine third-trimester ultrasound scan. The first scan was performed by an experienced ultrasonographer on an HSUM for fetal growth, fetal wellbeing and placental location. A second experienced operator performed the measurements on the PUM. Both operators were blinded to the other's findings and measurement results.

RESULTS

Fifty-one patients were eligible and scanned at a median gestational age of 31 + 1 (range, 27 + 2 to 36 + 0) weeks. Mean pregestational body mass index was 22.9 ± 3.1 (range, 17.6-35.7) kg/m(2) . In the comparison between measurements made using the PUM and HSUM, perfect agreement was found for fetal position, fetal bladder and stomach visualization (all κ 1.0) and very good agreement was found for placental position (κ 0.86). Measurements of deepest vertical pocket correlated moderately (intraclass correlation coefficient (ICC) 0.38 (95% CI, 0.12-0.59); Bland-Altman bias, 2.43 (95% limits of agreement (LoA), -22.65 to 27.51)). For fetal growth measurements there was very good agreement for biparietal diameter (ICC, 0.93 (95% CI, 0.88-0.96), Bland-Altman bias, -1.06 (95% LoA, -5.07 to 2.95)), and good agreement for femur length (ICC, 0.66 (95% CI, 0.48-0.79), Bland-Altman bias 0.56 (95% LoA, -5.97 to 7.08)) and transcerebellar diameter (ICC, 0.65 (95% CI, 0.46-0.78), Bland-Altman bias, -0.84 (95% LoA, -7.77 to 6.09)).

CONCLUSION

A battery-driven PUM can be used in third-trimester obstetrics for routine assessment of fetal growth (biparietal diameter, transcerebellar diameter and femur length) and for assessment of fetal wellbeing.

Strategies to diagnose ovarian cancer: new evidence from phase 3 of the multicentre international IOTA study

Background:

To compare different ultrasound-based international ovarian tumour analysis (IOTA) strategies and risk of malignancy index (RMI) for ovarian cancer diagnosis using a meta-analysis approach of centre-specific data from IOTA3.

Methods:

This prospective multicentre diagnostic accuracy study included 2403 patients with 1423 benign and 980 malignant adnexal masses from 2009 until 2012. All patients underwent standardised transvaginal ultrasonography. Test performance of RMI, subjective assessment (SA) of ultrasound findings, two IOTA risk models (LR1 and LR2), and strategies involving combinations of IOTA simple rules (SRs), simple descriptors (SDs) and LR2 with and without SA was estimated using a meta-analysis approach. Reference standard was histology after surgery.

Results:

The areas under the receiver operator characteristic curves of LR1, LR2, SA and RMI were 0.930 (0.917–0.942), 0.918 (0.905–0.930), 0.914 (0.886–0.936) and 0.875 (0.853–0.894). Diagnostic one-step and two-step strategies using LR1, LR2, SR and SD achieved summary estimates for sensitivity 90–96%, specificity 74–79% and diagnostic odds ratio (DOR) 32.8–50.5. Adding SA when IOTA methods yielded equivocal results improved performance (DOR 57.6–75.7). Risk of Malignancy Index had sensitivity 67%, specificity 91% and DOR 17.5.

Conclusions:

This study shows all IOTA strategies had excellent diagnostic performance in comparison with RMI. The IOTA strategy chosen may be determined by clinical preference.

Prevalence, potential risk factors for development and symptoms related to the presence of uterine niches following Cesarean section: systematic review

OBJECTIVE

To review systematically the medical literature reporting on the prevalence of a niche at the site of a Cesarean section (CS) scar using various diagnostic methods, on potential risk factors for the development of a niche and on niche-related gynecological symptoms in non-pregnant women.

METHODS

The PubMed and EMBASE databases were searched. All types of clinical study reporting on the prevalence, risk factors and/or symptoms of a niche in non-pregnant women with a history of CS were included, apart from case reports and case series.

RESULTS

Twenty-one papers were selected for inclusion in the review. A wide range in the prevalence of a niche was found. Using contrast-enhanced sonohysterography in a random population of women with a history of CS, the prevalence was found to vary between 56% and 84%. Nine studies reported on risk factors and each study evaluated different factors, which made it difficult to compare studies. Risk factors could be classified into four categories: those related to closure technique, to development of the lower uterine segment or location of the incision or to wound healing, and miscellaneous factors. Probable risk factors are single-layer myometrium closure, multiple CSs and uterine retroflexion. Six out of eight studies that evaluated niche-related symptoms described an association between the presence of a niche and postmenstrual spotting.

CONCLUSIONS

The reported prevalence of a niche in non-pregnant women varies depending on the method of detection, the criteria used to define a niche and the study population. Potential risk factors can be categorized into four main categories, which may be useful for future research and meta-analyses. The predominant symptom associated with a niche is postmenstrual spotting.

Are serum HE4 or ROMA scores useful to experienced examiners for improving characterization of adnexal masses after transvaginal ultrasonography?

OBJECTIVE

To determine whether serum human-epididymis protein-4 (HE4) levels or Risk of Ovarian Malignancy Algorithm (ROMA) scores are useful second-stage tests for tumors thought to be difficult to characterize as benign or malignant on the basis of ultrasound findings by experienced examiners, and to investigate whether adding information on serum HE4 levels or ROMA scores to ultrasound findings improves diagnostic performance.

METHODS

This was a prospective cross-sectional diagnostic accuracy study conducted in a tertiary referral center that enrolled consecutive women with a known adnexal mass scheduled for surgery. Experienced level III examiners classified each mass as certainly or probably benign, difficult to classify, or probably or certainly malignant after preoperative ultrasound examination. Serum HE4 and CA 125 levels were measured before surgery.

RESULTS

The final database comprised 360 women, of whom 216 (60%) had benign and 144 (40%) had malignant disease. Examiners were highly confident in 196 cases (54%), moderately confident in 135 (38%) and completely uncertain about their diagnosis in 29 (8%) cases. With a sensitivity of 67% and specificity of 70%, subjective assessment outperformed HE4 and ROMA in the subgroup of difficult tumors. Both tests had low discriminatory capacity with poor areas under the receiver-operating characteristics curve of 0.536 (95% CI, 0.302-0.771) and 0.565 (95% CI, 0.294-0.836), respectively. A strategy that incorporates sequential testing of serum HE4 or ROMA scores after transvaginal ultrasonography resulted in a deterioration in overall test performance.

CONCLUSION

Measurement of serum HE4 or calculating scores using the ROMA as secondary tests does not seem useful for classifying adnexal tumors after subjective assessment with transvaginal ultrasonography.

Ectopic pregnancy prediction in women with a pregnancy of unknown location: data beyond 48 h are necessary

STUDY QUESTION

Are there improvements in the accuracy of prediction of ectopic pregnancy (EP) in women with early symptomatic pregnancy using human chorionic gonadotrophin (hCG) curves when clinicians consider visits beyond the first 48 h after initial presentation?

SUMMARY ANSWER

Two hCG values, measured 48 h (2 days) apart, are often not sufficient to accurately predict the outcome of a woman with a pregnancy of unknown location (PUL), but adding a third visit on Day 4 or 7 significantly improved the prediction for 1 in 15 women.

WHAT IS KNOWN ALREADY

The use of serial hCG values is commonly used to aid in the prediction of the final diagnosis in women with a PUL. Initial outcome predictions based on two hCG values may often be incorrect.

STUDY DESIGN, SIZE, DURATION

This retrospective multicenter cohort study included 646 women with a PUL, recruited over 2 years. Of these women, 146 were ultimately diagnosed with EP.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women presenting to the emergency room with first trimester pain or bleeding, with a PUL, at least 2 hCG values and a definitive final diagnosis from the University of Pennsylvania, University of Miami and University of Southern California, were recruited from 2007 to 2009.

MAIN RESULTS AND THE ROLE OF CHANCE

Using currently recommended prediction rules, adding a third hCG evaluation on Day 4 after initial presentation significantly improved the accuracy of initial prediction from the first two values (48 h apart, or Day 2) by 9.3% (P = 0.015). Adding a third value on Day 7 improved prediction significantly by 6.7% (P = 0.031), compared with prediction based on first two values. The improvement in prediction by assessing four hCG values (Days 0, 2, 4 and 7) compared with three values (Days 0, 2 and 4) was 1.3% and not statistically significant.

LIMITATIONS, REASONS FOR CAUTION

Missing data imputation likely biased results toward the null; predicted outcomes may not match those made by clinicians; and the study does not predict intrauterine pregnancy and spontaneous miscarriage separately.

WIDER IMPLICATIONS OF THE FINDINGS

This study provides useful information for the prediction of outcomes for women with a symptomatic first trimester pregnancy of unknown location, but may not be generalizable to all pregnant women.

STUDY FUNDING/COMPETING INTEREST(S)

Supported by NIH grant numbers R01-HD036455 to Dr Barnhart and Dr Sammel, K24HD060687 to Dr Barnhart, and 5T32MH065218 to Ms. Zee. The authors have no conflicts of interest to declare.

Normative data for uterine size according to age and gravidity and possible role of the classical golden ratio

OBJECTIVES

To document normal measurements (length, width, anteroposterior (AP) diameter) and proportions of the non-pregnant uterus according to age and gravidity. We hypothesized that uterine proportions conform to the classical 'golden ratio' (1.618).

METHODS

This was a retrospective study of ultrasonographic measurements of the length, width and AP diameter of non-pregnant uteri recorded in our database between 1 January 2000 and 31 July 2012. All patients for whom abnormal findings were reported were excluded and only the first set of measurements for each patient was retained for analysis. Loess (local regression) analysis was performed using age and gravidity as explanatory variables.

RESULTS

Measurements of 5466 non-pregnant uteri were retrieved for analysis. The mean length was found to increase to 72 mm at the age of 40 and decrease to 42 mm at the age of 80 years. Gravidity was associated with greater uterine length, width and AP diameter. Mean length/width ratio was found to be 1.857 at birth, decreasing to 1.452 at the age of 91 years. At the age of 21 years, the mean ratio was found to be 1.618, i.e. equal to the golden ratio. Increasing gravidity was associated with lower mean length/width ratio.

CONCLUSIONS

Uterine size in non-pregnant women varies in relation to age and gravidity. Mean length/width ratio conformed to the golden ratio at the age of 21, coinciding with peak fertility.