Influence of endometrial thickness on pregnancy rates in modified natural cycle frozen-thawed embryo transfer.

INTRODUCTION: Pregnancy after frozen-thawed embryo transfer (FET) is a multifactorial process. Although embryo quality is a key factor in determining pregnancy, other factors, including maternal determinants, are also considered to be predictive. Even though an association between endometrial thickness measured by transvaginal ultrasound and pregnancy rates has been reported in patients undergoing various assisted reproductive technology treatments, whether endometrial thickness predicts achieving pregnancy after natural cycle FET (NC-FET) remains unclear. MATERIAL AND METHODS: In this cohort study, 463 patients allocated to the modified NC-FET (mNC-FET) arm of a previously published randomized controlled trial were included. Monitoring in mNC-FET cycles consisted of regular ultrasound scans, measuring both dominant follicle and endometrial thickness. When the dominant follicle reached a size of 16-20 mm, an injection of human chorionic gonadotrophin was administered and embryo thawing and transfer planned. No minimal endometrial thickness was defined below which transfer was to be deferred. The primary endpoint was ongoing pregnancy rate. RESULTS: Overall, the ongoing pregnancy rate per started FET cycle was 12.5%. Multivariate regression analyses showed that embryo quality was the only significant predictor for ongoing pregnancy. Mean endometrial thickness did not differ between patients achieving ongoing pregnancy and those who did not (9.0 vs. 8.8 mm, p = 0.4). Comparable results were obtained with regard to clinical pregnancy, live birth and miscarriage rates. The area under the receiver operator curve was 0.5, indicating little discriminatory value of endometrial thickness. CONCLUSIONS: Given that endometrial thickness was not found to be predictive of pregnancy after mNC-FET, cancellation based on endometrial thickness alone may not be justified.

The M-OVIN study: does switching treatment to FSH and / or IUI lead to higher pregnancy rates in a subset of women with world health organization type II anovulation not conceiving after six ovulatory cycles with clomiphene citrate - a randomised controlled trial.

BACKGROUND: Clomiphene citrate (CC) is first line treatment in women with World Health Organization (WHO) type II anovulation and polycystic ovary syndrome (PCOS). Whereas 60% to 85% of these women will ovulate on CC, only about one half will have conceived after six cycles. If women do not conceive, treatment can be continued with gonadotropins or intra-uterine insemination (IUI). At present, it is unclear for how many cycles ovulation induction with CC should be repeated, and when to switch to ovulation induction with gonadotropins and/or IUI. METHODS/DESIGN: We started a multicenter randomised controlled trial in the Netherlands comparing six cycles of CC plus intercourse or six cycles of gonadotrophins plus intercourse or six cycles of CC plus IUI or six cycles of gonadotrophins plus IUI.Women with WHO type II anovulation who ovulate but did not conceive after six ovulatory cycles of CC with a maximum of 150 mg daily for five days will be included.Our primary outcome is birth of a healthy child resulting from a pregnancy that was established in the first eight months after randomisation. Secondary outcomes are clinical pregnancy, miscarriage, multiple pregnancy and treatment costs. The analysis will be performed according to the intention to treat principle. Two comparisons will be made, one in which CC is compared to gonadotrophins and one in which the addition of IUI is compared to ovulation induction only. Assuming a live birth rate of 40% after CC, 55% after addition of IUI and 55% after ovulation induction with gonadotrophins, with an alpha of 5% and a power of 80%, we need to recruit 200 women per arm (800 women in total).An independent Data and Safety Monitoring Committee has criticized the data of the first 150 women and concluded that a sample size re-estimation should be performed after including 320 patients (i.e. 80 per arm). DISCUSSION: The trial will provide evidence on the most effective, safest and most cost effective treatment in women with WHO type II anovulation who do not conceive after six ovulatory cycles with CC with a maximum of 150 mg daily for five days. This evidence could imply the need for changing our guidelines, which may cause a shift in large practice variation to evidence based primary treatment for these women. TRIAL REGISTRATION NUMBER: Netherlands Trial register NTR1449.

Blood-borne angiogenic factors and sustained multiple implantation: a comparison of singleton and twin pregnancies.

This study aimed to compare longitudinal serum concentrations of angiogenic implantation factors between ongoing singleton and twin pregnancies after double-embryo transfer and to investigate whether these are involved in sustained double implantation. Sixteen patients with an ongoing singleton and nine patients with an ongoing twin pregnancy after double-embryo transfer were included in this prospective observational study. Main outcome measures were concentrations of vascular endothelial growth factor-A (VEGF-A), inhibin A, glycodelin A, insulin-like growth factor-I (IGF-I), insulin-like growth factor-II (IGF-II), insulin-like growth factor binding protein-1 (IGFBP-1) and insulin-like growth factor binding protein-3 (IGFBP-3) at baseline, during the IVF treatment and in early pregnancy. It appeared that VEGF-A concentrations prior to any treatment and at early implantation as well as body mass index (BMI) were higher in women who conceived a twin pregnancy (P = 0.04). Soon after implantation, inhibin A concentrations were higher in twin pregnancies (P=0.02). Secretion profiles of glycodelin A and members of the IGF family did not differ between singleton and twin pregnancies. VEGF-A appears to play a role in sustained double implantation. Furthermore a high BMI is associated with ongoing double implantation. Future studies should investigate the predictive value of VEGF-A for having an ongoing singleton or twin pregnancy.

Lower incidence of hypertensive complications during pregnancy in patients treated with low-dose aspirin during in vitro fertilization and early pregnancy.

BACKGROUND: The use of aspirin during in vitro fertilization (IVF) has been investigated for its effect on pregnancy rates after IVF. In most of these studies, aspirin administration was then prolonged throughout the first trimester of pregnancy. By inhibiting vasoconstriction, the use of low-dose aspirin in the first trimester could influence placentation and therefore prevent or delay development of hypertensive pregnancy complications, such as pregnancy-induced hypertension (PIH) and pre-eclampsia (PE). METHODS: This study involved the follow-up by questionnaires and hospital records of patients with an ongoing pregnancy in a prospective, randomized, double-blind, placebo-controlled trial on the effect of low-dose aspirin during IVF. Aspirin treatment was continued throughout the first trimester of pregnancy. The primary end-point of this follow-up study was the incidence of pregnancy complications. The original trial is registered with the Dutch Trial Register and as an International Standard Randomized Clinical Trial, No. ISRNCTM97507474. RESULTS: There were 54 patients who had ongoing pregnancies in the original trial; 90.7% returned the questionnaire and all Dutch hospital records were retrieved. A significant difference was found in the incidence of hypertensive pregnancy complications: 3.6% in the aspirin group and 26.9% in the placebo group (P < 0.05), resulting in numbers-needed-to-treat (NNT) of 10.3 to prevent hypertensive complications in one pregnancy after IVF treatment. CONCLUSIONS: The incidence of hypertensive complications was significantly lower in the group of women treated with low-dose aspirin throughout IVF treatment and first trimester of pregnancy. These results suggest a potential benefit of low-dose aspirin during IVF and first trimester to prevent hypertensive pregnancy complications. The findings justify further investigation in placebo-controlled randomized trials.

Low-dose aspirin in non-tubal IVF patients with previous failed conception: a prospective randomized double-blind placebo-controlled trial.

OBJECTIVE: To analyze whether the administration of low-dose aspirin during IVF treatment improves the uterine blood flow and improves ongoing pregnancy rates for non-tubal factor IVF patients with previous failed conception. DESIGN: Prospective double-blind placebo-controlled trial. SETTING: University fertility clinic. PATIENT(S): Non-tubal IVF patients with previous failed conception. INTERVENTION(S): Daily 100 mg aspirin or placebo throughout an IVF treatment with a long GnRH-agonist stimulation protocol. MAIN OUTCOME MEASURE(S): Ongoing pregnancy rate, pulsatility index of the uterine artery. RESULT(S): Of 169 patients, 84 were assigned to aspirin treatment and 85 to placebo treatment. In the aspirin group, 28 patients (35.4%) had an ongoing pregnancy, and in the placebo group, 26 patients (31.0%) had an ongoing pregnancy. Multilevel analyses showed that the pulsatility index of the uterine artery was not affected by aspirin or placebo treatment. CONCLUSION(S): Low-dose aspirin administration during IVF treatment does not improve pregnancy rates of non-tubal factor IVF patients with previous failed conception, and it does not affect the arterial uterine blood flow.

Effectiveness of highly purified human menopausal gonadotropin vs. recombinant follicle-stimulating hormone in first-cycle in vitro fertilization-intracytoplasmic sperm injection patients.

OBJECTIVE: To compare the effectiveness of highly purified hMG with recombinant FSH (rFSH) in IVF-intracytoplasmic sperm injection patients who were treated with a GnRH agonist. DESIGN: An open-label, prospective, randomized comparison of fixed gonadotropin regimens. SETTING: Eighteen Dutch IVF centers. PATIENT(S): Six hundred twenty-nine patients who were selected for IVF-intracytoplasmic sperm injection. INTERVENTION(S): Patients were randomized to receive either highly purified hMG or rFSH in a fixed dosage of 150 IU/d after GnRH-agonist suppression (long protocol). MAIN OUTCOME MEASURE(S): Ongoing pregnancy rate per started cycle. Difference between the two treatment groups was tested by using odds ratios, including the 95% confidence limits (intention-to-treat sample), and by using the Fisher's exact test (per-protocol sample). RESULT(S): The ongoing pregnancy rates per started cycle were 26.3% and 25.2% for highly purified hMG and rFSH, respectively (no statistically significant difference). Treatment with highly purified hMG resulted in statistically significantly fewer oocytes (n = 7.8) than did treatment with rFSH (n = 10.6). There were no differences with respect to fertilization rates and implantation rates. Cycles with highly purified hMG were statistically significantly less often canceled as a result of ovarian hyperresponse (2.0% vs. 6.0% for highly purified hMG and rFSH, respectively). CONCLUSION(S): Compared with rFSH, highly purified hMG did not result in superiority in ongoing pregnancy rates in first-cycle IVF-intracytoplasmic sperm injection patients who were treated with a fixed dosage of 150 IU of gonadotropin per day. Compared with rFSH, treatment with highly purified hMG resulted in retrieval of fewer oocytes, a lower incidence of hyperresponse, and comparable pregnancy rates.

Human embryo implantation: current knowledge and clinical implications in assisted reproductive technology.

A pregnancy rate of approximately 15% per cycle renders the process of human reproduction inefficient. The cycle-dependent expression of molecules involved in the embryo-endometrial dialogue has lead to the identification of a 'window of implantation'. This is the unique temporal and spatial expression of factors that allows the embryo to implant (via signalling, appositioning, attachment and invasion) in a specific time frame of 48 h, 7-10 days after ovulation. Integrin molecules, L-selectin ligands, mucin-1, heparin-binding epidermal growth factor and pinopodes are involved in appositioning and attachment. The embryo produces cytokines and growth factors [interleukins, prostaglandins, vascular endothelial growth factor (VEGF)] and receptors for endometrial signals (leukaemia inhibitory factor receptor, colony stimulating factor receptor, insulin-like growth factors and heparin binding epidermal growth factor receptor). The immune system plays an important role. Immunomodulatory factors such as glycodelin, inhibin and interleukin prevent a graft-versus-host reaction. Angiogenesis controlled by VEGF and prostaglandins is needed for formation of a receptive endometrium and a placenta. Identification of these factors has led to their use as markers of implantation that may identify defects causing subfertility. An ideal marker of implantation is sensitive and specific, and easy to obtain without disturbing implantation. Glycodelin and leukaemia inhibitory factor (serum) and integrins and pinopodes (biopsies) are promising candidates.