Role of Doppler ultrasonography in the prediction of pregnancy outcome in women with recurrent spontaneous abortion

Resistance of uterine radial artery blood flow was correlated with peripheral blood NK cell fraction and improved with low molecular weight heparin therapy in women with unexplained recurrent pregnancy loss

PROBLEM

To investigate whether peripheral blood natural killer (pbNK) cell levels are associated with uterine blood flow, and low molecular weight heparin (LMWH) treatment is effective to improve uterine blood flow in women with decreased uterine blood flow and unexplained recurrent pregnancy loss (RPL).

METHOD OF STUDY

This was a prospective controlled study. Study population included 33 pregnant women (between 5 and 7 weeks gestation) with ≥ 2 RPL and controls were 47 healthy pregnant women. pbNK cell fractions (CD3(-)/56(+)/16(+)) of peripheral blood mononuclear cells were measured by flow cytometry. Uterine color-pulsed Doppler ultrasound was performed to evaluate uterine radial artery resistance index (URa-RI). In RPL women with elevated URa-RI (≥ 0.5), LMWH (ranges 40-60 mg/day) was administered subcutaneously daily and URa-RI was reassessed 1 week later. Pregnancy outcome was analyzed at 12 weeks gestation.

RESULTS

URa-RI was significantly higher in pregnant women with RPL than controls (0.60 ± 0.14 versus 0.54 ± 0.12, P = 0.039). In pregnant women with RPL, pbNK cell fractions displayed a positive correlation with URa-RI (Pearson's r = 0.429, P = 0.013). URa-RI was significantly decreased 1 week after LMWH treatment as compared to that of pretreatment (pretreatment RI: 0.65 ± 0.11 versus post-treatment RI: 0.56 ± 0.13, P = 0.011). Pregnancy outcome of RPL women with LMWH treatment was not different from that of pregnant controls (73.3% versus 85.0%, P = NS).

CONCLUSION

Increased pbNK cells are associated with decreased uterine radial artery blood flow. LMWH treatment effectively decreases URa-RI with improved pregnancy outcome in women with RPLs and elevated URa-RI. A larger scale study is needed to verify these findings.

Elevated natural killer cell levels and autoimmunity synergistically decrease uterine blood flow during early pregnancy

Objective

To investigate whether natural killer (NK) cell and autoimmune antibody acts synergistically, by the action of autoantibodies to increase NK cell number and cytotoxicity, to decrease uterine blood flow during early pregnancy in pregnant women with a history of recurrent spontaneous abortion (RSA).

Methods

Seventy-five pregnant women (between 5 and 7 weeks gestation) with a history of unexplained RSA were included in the study group. Forty-one pregnant women without a history of RSA were included as controls. All women with a history of RSA were tested for autoantibodies and number of peripheral blood natural killer (pbNK) cell by flow cytometry. Study populations were stratified into four groups by existence of autoantibody and degree of increase of pbNK cells. The uterine radial artery resistance index (RI) was measured by color-pulsed Doppler transvaginal ultrasound.

Results

The mean RI of the autoimmune antibody-positive (AA+) group (0.63±0.09) was significantly higher than that of the normal control group (0.53±0.10, P=0.001). The mean RI of the AA+/only-NK elevated (eNK) group (0.63±0.09) was significantly higher than those of the only-AA+ group (0.55±0.07, P=0.019) and the only-eNK group (0.57±0.07, P=0.021).

Conclusion

Concurrent elevation in NK cells and autoimmunity results in decreased uterine blood flow during early pregnancy. However, the majority of cases of RSA remain unexplained and larger scale studies are needed to confirm our conclusion and to develop diagnostic and therapeutic plans for women with a history of RSA.

Low endometrial volume may predict early pregnancy loss in women undergoing in vitro fertilization

PURPOSE

To evaluate the role of 3-D US measurement of the endometrium during early IVF-pregnancy and before the appearance of gestational sac in the prediction of pregnancies outcome.

METHODS

60 pregnant women following IVF treatment were included in the study. The women underwent transvaginal 3D US measurements of endometrial volume and thickness on day 15-17 post ET. Patients were followed and classified according to pregnancy outcome into 2 further groups. The group with early pregnancy loss and the group with ongoing pregnancy.

RESULTS

While no differences were observed between those who miscarried and those who did not in gestational age, endometrial thickness or volume, spontaneous early pregnancy loss was significantly higher in patients with endometrial volume <2 mL as compared to those with endometrial volume >2 mL.

CONCLUSIONS

3-D US measurement of endometrial volume of less than 2 mL during early IVF pregnancy and prior to the appearance of gestational sac is a powerful predictor of pregnancy loss.

Endometrial and subendometrial vascularity is higher in pregnant patients with livebirth following ART than in those who suffer a miscarriage

BACKGROUND

Blood flow towards the peri-implantation endometrium may have effects on miscarriage and live birth following assisted reproduction treatment, in addition to its role in implantation.

METHODS

Three-dimensional ultrasound examination with power Doppler was performed on the day of oocyte retrieval in stimulated IVF cycles and on LH + 1 day in frozen thawed-embryo transfer (FET) cycles to measure endometrial thickness, endometrial pattern, uterine artery Doppler flow indices, endometrial volume, vascularization index (VI), flow index (FI), vascularization flow index (VFI) of endometrial and subendometrial regions.

RESULTS

In stimulated IVF cycles, 45 (28.0%) out of 161 pregnant patients subsequently miscarried. Patients in the live birth group had significantly higher endometrial VI and VFI and subendometrial VI, FI and VFI, when compared with those in the miscarriage group. In a multiple logistic regression analysis, only endometrial VI was significantly associated with the chance of live birth with an odds ratio of 1.384 [95% confidence interval (CI) 1.025-1.869, P = 0.034]. For FET cycles, patients in the live birth group had significantly higher endometrial VFI, subendometrial VI and VFI than those in the miscarriage group.

CONCLUSIONS

Endometrial and subendometrial vascularity was significantly higher in pregnant patients with live birth following stimulated IVF and FET treatment than in those who suffered a miscarriage.

First-trimester Doppler investigation of the uterine circulation

There is now strong evidence that fetal events can significantly impact postnatal health and disease development. Doppler velocimetry can identify some early pathologic changes in pregnancy. Many investigators have tried to delineate the normal and pathologic models of the uterine circulation in the first trimester, but much has yet to be defined. A discrete amount of confusion derives from the incomplete knowledge of the initial placental development, and particularly the development of the intervillous circulation. This article comprehensively reviews the literature on first-trimester Doppler in both normal and complicated pregnancies, and briefly discusses potential future areas of application.

The role of ultrasound imaging in diagnosing and investigating early pregnancy failure

The advent of high-resolution transvaginal ultrasound (TVS) has revolutionized our understanding of the pathophysiology and the management of early pregnancy failure. Knowledge of the ultrasound appearances of normal early pregnancy development and a good understanding of its pitfalls are essential for the diagnosis and management of early pregnancy failure. Ultrasound imaging has rapidly replaced all other techniques used to study normal human development in the first trimester, and ultrasound features of the early gestational sac have corroborated anatomical studies showing that the first structures to appear are the celomic cavity and the secondary yolk sac. No single ultrasound measurement of the different anatomical features in the first trimester has been shown to have a high predictive value for determining early pregnancy outcome. Similarly, Doppler studies have failed to demonstrate abnormal blood flow indices in the first-trimester uteroplacental circulation of pregnancies that subsequently end in miscarriage. Ultrasound parameters combined with maternal serum hormone levels, maternal age, smoking habits, obstetric history and the occurrence of vaginal bleeding have all been combined in multivariate analyses, with mixed results. Combined ultrasound and in-vitro experiments have demonstrated that the maternal circulation inside the placenta starts at the periphery at around 9 weeks of gestation and that this is associated with a physiological oxidative stress which could be the trigger for the formation of the placental membranes. Abnormal development of these membranes can result in subchorionic hemorrhage and threatened miscarriage with subsequent long-term consequences such as preterm rupture of the membranes and preterm labor, irrespective of the finding of a hematoma on ultrasound. In both euploid and aneuploid missed miscarriages there is clear ultrasound evidence for excessive entry of maternal blood at a very early stage inside the developing placenta resulting in oxidative stress and subsequent degeneration of villous tissue. The finding of blood flow in the intervillous space in cases of first-trimester miscarriage using color Doppler also appears to be useful in the prediction of success of expectant management. Miscarriages with blood flow within the intervillous space are up to four times more likely to complete with expectant management. TVS is considered the gold standard in the diagnosis and management of incomplete miscarriage. Expectant management of miscarriage, using ultrasound parameters to determine eligibility, could significantly reduce the number of unnecessary evacuations of the retained products of conception, depending on the criteria used.

Impaired uterine arterial blood flow in pregnant women with recurrent pregnancy loss

OBJECTIVE

This study was undertaken to evaluate uterine perfusion, which regulates uterine receptivity, in women with recurrent pregnancy loss.

METHODS

We evaluated the blood flow resistance in the uterine arteries of 104 pregnant women at 4 to 5 weeks' gestation by transvaginal pulsed Doppler ultrasonography (control group, n = 52; and recurrent pregnancy loss group, n = 52). Blood tests for antinuclear and antiphospholipid antibodies were also performed.

RESULTS

The uterine arterial pulsatility index in the recurrent pregnancy loss group was significantly higher than that in the control group. Women with antinuclear or antiphospholipid antibodies had an elevated pulsatility index in the uterine artery, which is prominent in women with recurrent pregnancy loss. Coagulopathy and vascular dysfunction caused by autoantibodies may impair uterine perfusion. However, the uterine arterial pulsatility index in the recurrent pregnancy loss group was significantly higher than that in the control group even among women without antinuclear antibodies or among women without antiphospholipid antibodies. This observation strongly suggests that the uterine artery pulsatility index may be an independent index for recurrent pregnancy loss.

CONCLUSIONS

The introduction of pulsed Doppler ultrasonography has provided the means for noninvasive evaluation of uterine impedance and may identify patients with recurrent pregnancy loss associated with impaired uterine perfusion.

Increased pregnancy loss in young women with aortoiliac disease

BACKGROUND

During clinical evaluation of young women with peripheral arterial occlusive disease, we were surprised by the high prevalence of pregnancy loss in women with segmental stenosis confined to the aortoiliac segment. We wondered if increased occurrence of miscarriage is the result of high expression of vascular and obstetrical risk factors in these patients, or if it is related to localization of disease. In a case-control study designed to investigate risk factors for peripheral arterial occlusive disease in young women, we assessed the risk of miscarriage in these patients according to level of obstruction.

METHODS

A total of 202 female patients, aged 18-49 years and 466 healthy control women from a population based case-control study, donated venous blood samples and filled out a structured questionnaire concerning classical cardiovascular risk factors and obstetrical history. In all patients, diagnosis of peripheral arterial occlusive disease was confirmed by intra-arterial angiography. Patients were classified into two groups: those with and those without stenosis of the aortoiliac segment (aortoiliac disease).

RESULTS

In 77 of the 202 patients (38%) with peripheral arterial occlusive disease, the obstruction was confined to the aortoiliac segment. The occurrence of miscarriage was high (42%) in young women with aortoiliac disease. Compared to healthy controls, the risk of miscarriage increased 3-fold (OR 3.1; 95% CI 1.8-5.6) in these patients. Adjustment for obstetrical and vascular risk factors did not affect the risk estimate.

CONCLUSION

This is the first study that identifies aortoiliac disease as a risk factor for pregnancy loss in young women. The risk of miscarriage is increased 3-fold in women with aortoiliac disease. The presence of vascular and obstetrical risk factors did not affect the strength of the association. Pregnancy loss could be the first sign of insufficient aortic circulation in these patients.