The relevance of endometrial thickness and echo patterns for the success of in vitro fertilization evaluated in 148 patients

A meta-analysis of the relationship between endometrial thickness and outcome of in vitro fertilization cycles

OBJECTIVE:

The objective was to evaluate the relationship between endometrial thickness on the day of human chorionic gonadotropin administration and pregnancy outcome in in vitro fertilization cycles.

DESIGN:

This was a systematic review and meta-analysis.

MATERIALS AND METHODS:

We identified 484 articles using Cochrane library, PubMed, Web of Science, and Embase searches with various key words including endometrial thickness, pregnancy, assisted reproductive technology, endometrial pattern, and in vitro fertilization. A total of 14 studies with data on endometrial thickness and outcome were selected, representing 4922 cycles (2204 pregnant and 2718 nonpregnant). The meta-analysis with a random effects model was performed using comprehensive meta-analysis software. We calculated the standardized mean difference, odds ratio (OR), and 95% confidence intervals (CIs).

RESULTS:

There was a significant difference in the mean endometrial thickness between pregnant and nonpregnant groups (P<0.001), with a standardized mean difference of 0.4 mm (95% CI 0.22–0.58). The OR for pregnancy was 1.40 (95% CI 1.24–1.58).

CONCLUSIONS:

The mean endometrial thickness was significantly higher in pregnant women compared to nonpregnant. The mean difference between two groups was <1 mm which may not be clinically meaningful. Although there may be a relationship between endometrial thickness and pregnancy, implantation potential is probably more complex than a single ultrasound measurement can determine.

Endometrial evaluation in superovulation programs: relationship with successful outcome

It is well known that an adequate endometrial receptivity is required for successful implantation in both natural and assisted reproductive cycles. In particular, a brief "implantation window", during which endometrium undergoes anatomical and molecular changes necessary for embryo implantation, has been observed. The hormonal treatment applied to induce ovulation seems to be able to modify the normal development of the prenidatory endometrium, with possible negative effect on the implantation rate. For this reason, several attempts have been made to identify specific markers of endometrial receptivity, useful for predicting implantation outcome in clinical practice. Even if different histological, immunohistochemical, and ultrasonographic parameters are studied, none unfortunately has been univocally shown to be predictive of pregnancy outcome. Therefore, the evaluation of endometrial receptivity remains a challenge in clinical practice.

A suboptimal endometrial pattern is associated with a reduced likelihood of pregnancy after a day 5 embryo transfer

This retrospective study examined the association of endometrial pattern and pregnancy after a day 5 ET. The pregnancy rate of women with a triple-line ultrasound endometrial pattern on the day of hCG administration was significantly higher than the pregnancy rate of women with the other ultrasound patterns. This observation suggests that, in a subset of patients, a suboptimal endometrial lining may interfere with assisted reproductive technology success.

Subendometrial contractility is not predictive for in vitro fertilization (IVF) outcome

OBJECTIVES

The aim of the study was to investigate whether endometrial thickness, endometrial pattern, endometrial movement and serum estradiol and progesterone affect the outcome of in vitro fertilization.

METHODS

Prospectively collected data of endometrial thickness, endometrial pattern and subendometrial activity were analyzed in 122 consecutive in vitro fertilization cycles. All measurements were made on the day of hCG administration (day -2), day of embryo transfer (day +2), day +6 and day +12.

RESULTS

It would appear that pregnant women tend to have a thicker endometrium on day +12 than non-pregnant women. There appears to be no appreciable difference between pregnant and non-pregnant women in endometrial movement and thickness, nor in serum estradiol and progesterone on day +2 and day +6. In combining three echographic variables (thickness, pattern and movement) and hormone level (estradiol and progesterone), only progesterone on day +12 could be used to predict the outcome.

CONCLUSIONS

Subendometrial contractility plays no important role in implantation on the day of embryo transfer or 4 days later.

Power Doppler endometrial evaluation as a method for the prognosis of embryo implantation in an ICSI program

PURPOSE

The objective of the present study was to evaluate power Doppler of the endometrium as a parameter for the prognosis of embryo implantation in patients who underwent intracytoplasmic sperm injection (ICSI).

METHODS

The power Doppler was performed on a transverse section at the level of the uterine fundus on the day of human chorionic gonadotropin in 185 patients who submitted to ovarian stimulation for ICSI. The endometrium was divided into four equal quadrants and classified as grade I, II, III, or IV according to the visualization of the power Doppler in the quadrants. The color Doppler signal was considered to be positive when it reached at least the basal layer of the endometrium.

RESULTS

Age, number of days of stimulation, number of follicles > or = 16 mm, number of oocytes in metaphase II retrieved, and fertilization rate did not differ patients with the four different types of endometrial grades. Endometrial thickness and the pulsatility index of uterine artery also were similar for the four grades. The rate of embryo implantation also did not differ significantly (P = 0.53) among groups: grade I = 10%; grade II = 11.6%; grade III = 15.4%; grade IV = 10.5%. The pregnancy rates were grade I = 25%; grade II = 29.7%; grade III = 37.5%; grade IV = 23.8% (P = 0.44).

CONCLUSIONS

Our data demonstrate that isolated evaluation of endometrial vascularization with power Doppler is not an important factor for the prediction of pregnancy in an ICSI program.

Endometrial pattern on the day of oocyte retrieval is more predictive of implantation success than the pattern or thickness on the day of hCG administration

PURPOSE

Multiple studies have confirmed a lower implantation (IR) and pregnancy rate (PR) in women who exhibit a homogeneous pattern (pattern II) of the endometrium compared to a triple-line pattern (pattern I) on the day of hCG administration. However, no data are available to evaluate if patients alter their endometrial thickness and pattern between the day of hCG administration (DhCG) and the day of oocyte retrieval (DRET) and whether these changes adversely affect endometrial receptivity.

METHODS

We prospectively evaluated 86 women (mean age, 32.9 +/- 3.8 years; range, 24-40 years) undergoing 103 IVF/ET cycles.

RESULTS

Pattern II was noted in 7 cycles (6.8%) on DhCG, compared to 96 cycles with pattern I (93.2%). However, 20 cycles (19.4%) had pattern II on DRET. The ongoing IR was 13.0% (3/23) in the pattern II group compared to 20.8% (76/365) in the pattern I group on DhCG (P = NS). However, a significant decrease in the ongoing IR, to 9.9% (7/71), was noted in pattern II, compared to 23.3% (71/305) in pattern I, on DRET (P = 0.019). There was no difference in age, basal FSH, peak E2, P4 on the day of hCG, number of oocytes, number of ET, or endometrial thickness between pregnant and nonpregnant patients, or between patients with pattern I and those with pattern II. A trend toward higher progesterone levels on DhCG was noted in women with pattern II (P = 0.078).

CONCLUSIONS

Endometrial pattern, rather than thickness, on the day of oocyte retrieval appears to be an important prognosticator of endometrial receptivity.

Relationship of the individual uterine size and the endometrial thickness in stimulated cycles

At present there is no agreement regarding the usefulness of monitoring the endometrial thickness in stimulated cycles. We tested prospectively the hypothesis of a linear relationship of the given individual uterine size and the endometrial thickness in stimulated cycles using a 240 degrees transvaginal sector scanner. There was a strong correlation of the uterine dimension with the endometrial thickness in the midfollicular and the early luteal phase. Our findings suggest that the endometrial thickness is determined by the individual uterine architecture and therefore not predictive of the likelihood of implantation.