Effect of Oral Contraceptive Use in Relation to Fertile Years on the Risk of Endometriosis in Women with Primary Infertility: A Ten-Year Single-Centre Retrospective Analysis.

Background and Objectives: Oral contraceptives (OCs) are usually used to treat endometriosis; however, the evidence is inconsistent about whether OC use in the past, when given to asymptomatic women, is protective against the development of future disease. We aimed to assess the relationship between the use of OCs and the likelihood of discovering endometriosis, considering the length of time under OCs during their fertile age. Materials and Methods: This was a monocentric retrospective cohort study in a tertiary-care University Hospital (Department of Human Reproduction, Division of Gynaecology and Obstetrics, University Medical Centre Ljubljana, Slovenia) carried out from January 2012 to December 2022. Reproductive-aged women scheduled for laparoscopic surgery for primary infertility and subsequent histopathological diagnosis of endometriosis were compared to women without an endometriosis diagnosis. They were classified based on the ratio of years of OC use to fertile years in four subgroups: never, <25%, between 25 and 50%, and >50. Results: In total, 1923 women (390 with and 1533 without endometriosis) were included. Previous OC use was higher in those with endometriosis than controls (72.31% vs. 58.64%; p = 0.001). Overall, previous OC usage was not related to histopathological diagnosis of endometriosis (aOR 1.06 [95% CI 0.87-1.29]). Women who used OCs for less than 25% of their fertile age had reduced risk of rASRM stage III endometriosis (aOR 0.50 [95% CI 0.26-0.95]; p = 0.036) or superficial implants (aOR 0.88 [95% CI 0.58-0.95]; p = 0.040). No significant results were retrieved for other rASRM stages. Using OCs for <25%, between 25 and 50%, or >50% of fertile age did not increase the risk of developing superficial endometriosis, endometriomas, or DIE. Conclusions: When OCs are used at least once, histological diagnoses of endometriosis are not increased. A protective effect of OCs when used for less than 25% of fertile age on superficial implants may be present. Prospective research is needed to corroborate the findings due to constraints related to the study's limitations.

Coexistence of Endometriosis and Thyroid Autoimmunity in Infertile Women: Impact on in vitro Fertilization and Reproductive Outcomes.

OBJECTIVES: The objective of the study was to evaluate the prevalence and impact of impaired thyroid-stimulating hormone (TSH) levels on the reproductive outcomes of in vitro fertilization patients diagnosed with endometriosis and compared to controls without endometriosis. DESIGN: This is a retrospective cohort study on prospectively collected data. SETTING: The study was conducted at tertiary care university hospital. PARTICIPANTS: Participants were infertile women with histopathological diagnosis of endometriosis. METHODS: For 12 months (January 2018 to January 2019), women were deemed suitable and subsequently divided according to serum TSH levels above or below 2.5 mIU/L and compared to patients without endometriosis. Needed sample size was at least 41 patients for each cohort of women. Co-primary outcomes were the live birth rate (LBR), clinical pregnancy rate (CPR), and pregnancy loss rate (PLR). RESULTS: Overall, 226 women (45 with endometriosis and 181 controls without endometriosis) were included. Diagnoses of Hashimoto thyroiditis were significantly more frequent in women with rather than without endometriosis (14/45 [31.1%] vs. 27/181 [14.9%]; p = 0.012). Similarly, in women with endometriosis, Hashimoto diagnosis rates were higher with TSH ≥2.5 mIU/L compared to TSH <2.5 mIU/L (9/15 [60%] vs.5/30 [16.6%]; p = 0.001) so were the Hashimoto diagnosis rates in control group (women without endometriosis) with TSH ≥2.5 mIU/L compared to TSH <2.5 mIU/L (17/48 [35.4%] vs. 10/133 [7.5%], respectively; p = 0.001). Effect size analysis confirmed an increased risk of Hashimoto thyroiditis in women with endometriosis and TSH ≥2.5 mIU/L compared to women with endometriosis and TSH <2.5 mIU/L (risk ratio [RR] 3.60 [95% CI 1.46-8.86]) and in women with endometriosis and TSH ≥2.5 mIU/L compared to non-endometriotic euthyroid patients (RR 7.98 [95% CI 3.86-16.48]). Dysmenorrhea risk was higher in endometriotic euthyroid women compared to euthyroid patients with no endometriosis (RR 1.87 [95% CI 1.21-2.87]). The risk was still increased in euthyroid women with endometriosis relative to dysthyroid women with no endometriosis (RR 1.97 [95% CI 1.11-3.50]). There were no significant differences between the four groups for CPR, LBR, PLR and retrieved oocytes, immature oocytes, degenerated and unfertilized oocytes, cultured blastocysts, embryos and transferred embryos. LIMITATIONS: Limitations of the study were retrospective design, limited sample size, and use of different ovarian stimulation protocol. CONCLUSIONS: Thyroid autoimmunity seems more common in women with endometriosis and TSH over 2.5 mIU/L. However, there was no significant impact on in vitro fertilization and reproductive outcomes related to the coexistence of endometriosis, Hashimoto disease, and higher TSH levels. Due to limitations of the study, additional evidence is required to validate the abovementioned findings.

Pathology of the Placenta in Singletons after Assisted Reproductive Technology Compared to Singletons after Spontaneous Conception: A Systematic Review.

Background: We reviewed the literature comparing the pathological characteristics of singleton births conceived after assisted reproductive technology (ART) with those after spontaneous conception. Methods: We reviewed PubMed, EMBASE, Ovid MEDLINE, Google Scopus, Scholar, Cochrane Central Register of Controlled Trials and the Web of Science for the previous 10 years, up to November 2022. Results: Four eligible studies included 3445 placentas, 806 after ART (IVF/ICSI). Placentas after ART differed in frequency of retroplacental and marginal hematomas (p = 0.04), increased thickness (p = 0.02), higher overall occurrences of vascular and anatomical pathology (p < 0.001) and more frequent marginal (p = 0.001) and membranous (p = 0.02) umbilical cord insertion than placentas from non-ART pregnancies. Conclusion: Further research is needed to determine the extent to which these placental changes in ART pregnancies alter its function and pregnancy outcome.

Reproductive Outcome After GnRH Agonist Triggering With Co-Administration of 1500 IU hCG on the Day of Oocyte Retrieval in High Responders: A Long-Term Retrospective Cohort Study.

While triggering oocyte maturation with GnRH agonist (GnRHa) seems to be safe and effective in terms of the risk of developing OHSS and the number of metaphase II oocytes, it nevertheless results in luteal phase deficiency. To date, strategies have been developed in order to rescue defective luteal phase of GnRHa triggered cycles. Our study aimed to assess the reproductive outcome of GnRHa triggered cycles combined with modified luteal support (1500 IU hCG at the day of oocyte retrieval) in women with high ovarian response and to compare the outcome with hCG triggered cycles in GnRH antagonist IVF-ICSI procedures. A retrospective cohort database review of the results of GnRH antagonist IVF-ICSI cycles was conducted at a tertiary-care IVF center in Ljubljana, Slovenia. A total of 6126 cycles, performed from January 1, 2014, to December 31, 2020, were included in the final analysis. Final oocyte maturation was performed with either 5000, 6500, or 10,000 IU hCG (women with normal ovarian response) or 0.6 mg GnRHa (buserelin), supplemented with 1500 IU hCG on the day of oocyte retrieval (in women with high ovarian response). In cases of excessive ovarian response and/or high risk of OHSS luteal support was not introduced and all good quality blastocysts were frozen. According to significant differences in patients' age and the number of oocytes in the two groups, matching by age and number of oocytes was performed. No significant differences were observed regarding pregnancy rate per embryo transfer, rate of early pregnancy loss, and livebirth rate per pregnancy between the GnRHa and hCG trigger groups, respectively. A significant difference in the number of developed embryos and blastocysts, as well as the number of frozen blastocysts, was seen in favor of the GnRHa trigger. However, the birth weight in the GnRHa trigger group was significantly lower. Conclusion: The results of our study support the use of GnRHa for final oocyte maturation in GnRH antagonist IVF cycles in women with high ovarian response. Luteal phase rescue was performed by co-administration of 1500 IU hCG on the day of oocyte retrieval and estradiol and progesterone supplementation. In our experience, such an approach results in a comparable reproductive outcome with hCG trigger group.

Does Hysteroscopic Dissection of Partial Uterine Septum Represent a Risk Factor for Placental Abnormalities in Subsequent Pregnancy Compared with Controls Undergoing Other Hysteroscopic Surgery? Results from a Large Case-Control Analysis.

BACKGROUND: Hysteroscopic septum dissection (HSD) is thought to improve fertility and pregnancy outcomes. However, the available literature suggests that uterine surgery can cause placental abnormalities in subsequent pregnancies. METHODS: A case-control study was performed at the University Medical Center of Ljubljana, Department of Human Reproduction, from 1 January 2016 to 31 December 2018. The primary outcome was the association between HSD and the occurrence of placental abnormalities. We included women who underwent HSD due to infertility. Age-matched women who underwent hysteroscopic surgery for other issues were considered as controls. In addition, we divided the groups according to conception method. Only singleton pregnancies and first delivery were considered. RESULTS: A total of 1286 women (746 who underwent HSD and 540 controls) were included in the analysis. HSD had no influence on placental abnormalities since the ratio was comparable regardless of the method of conception (113/746 vs. 69/540; p = 0.515). Infertile women who conceived naturally after HSD had a normal placentation rate comparable to women who did not undergo HSD (380/427 vs. 280/312; p = 0.2104). The rate of placental abnormalities in women who achieved pregnancy with IVF/ICSI procedures following HSD was comparable to that of women who did not undergo HSD (52/319 vs. 33/228; p = 0.5478). Placenta previa occurred significantly more often in infertile women without HSD after IVF/ICSI compared to natural conception (2/312 vs. 7/228; p = 0.0401). CONCLUSIONS: HSD was not associated with higher rate of placental abnormalities in the first singleton pregnancy compared with other hysteroscopic procedures. A higher rate of placenta previa in pregnancies following IVF/ICSI procedures, which was shown by our research, is corroborated by previous research findings.

Preterm delivery risk in infertile women who conceived after reproductive surgery: natural conception versus IVF/ICSI.

STUDY QUESTION: Is preterm delivery an infertility treatment-related adverse outcome in infertile women who conceived after reproductive surgery? SUMMARY ANSWER: Compared with matched fertile women, preterm delivery appears to be a modest infertility treatment-related adverse outcome in infertile women who have reproductive surgery then conceived naturally or after IVF/ICSI. WHAT IS KNOWN ALREADY: Most observational studies have shown that women who receive any infertility treatment are more likely to deliver preterm than do fertile women. However, studies on the outcome of pregnancies in infertile women who conceive naturally after reproductive surgery are scarce. STUDY DESIGN, SIZE, DURATION: This was a single-centre historical two-part study: cohort and matched cohort study. Anonymized data of 761 infertile women who conceived after reproductive surgery and 758 fertile women were obtained by linking three computerized databases from 1 July 2012 to 31 December 2015. PARTICIPANTS/MATERIALS, SETTING, METHODS: In the cohort study, we evaluated the association between the mode of conception and preterm delivery <37 and <32 gestational weeks in 703 infertile women, with a singleton pregnancy who conceived after reproductive surgery, using logistic regression adjusted for relevant co-variates to calculate the adjusted odds ratio with a 95% CI. In the matched cohort study, we evaluated preterm delivery as infertility treatment-related adverse outcome using the propensity score (PS) method. The matched cohort comprised 758 infertile women and 758 fertile women with a twin or singleton pregnancy. Infertile women conceived after reproductive surgery either naturally or through IVF/ICSI. Infertile and fertile women were matched using PS matching. Infertile and fertile women were matched for pre-defined risk factors for preterm delivery. Three infertile women out of an original 761 were not included in the analysis because they lacked all required matching variables. We performed a 1:1 matching with an optimal matching algorithm with a caliper width of the linear predictor of 0.1 standard deviations. The effect of reproductive surgery on preterm delivery was evaluated in the PS-matched sample using Pearson's χ2 test and presented as the odds ratio (OR) with 95% CI. All women delivered at the Department of Perinatology, University Medical Centre Ljubljana, Slovenia. MAIN RESULTS AND THE ROLE OF CHANCE: Among 761 infertile women who conceived after reproductive surgery, 428 (56.2%) women conceived naturally and 333 (43.8%) conceived after IVF/ICSI. The incidence of twin pregnancies was significantly lower after natural conception (2.6% vs 14.1%). Among the 703 infertile women with a singleton pregnancy, 417 (59.3%) conceived naturally and 286 (40.7%) conceived after IVF/ICSI. Adjusted for maternal age and parity in infertile women with singleton pregnancies, IVF/ICSI showed a moderate association with preterm delivery <32 weeks. Compared with natural conception after reproductive surgery, the odds for preterm delivery after IVF/ICSI was 1.07 (95% CI 0.63-1.81) <37 weeks and 2.25 (95% CI 0.80-6.34) <32 weeks. Preterm delivery appears to be a modest infertility treatment-related adverse outcome. Compared with fertile women in the PS-matched sample, infertile women who conceived after reproductive surgery either naturally or after IVF/ICSI the odds of preterm delivery <37 weeks were 1.31 (95% CI 0.97-1.78) and odds of preterm delivery <32 weeks were 1.57 (95% CI 0.78-3.18). However, none of the estimations were statistically significant. LIMITATIONS, REASONS FOR CAUTION: The main limitations of the study were the retrospective design, the heterogeneity of the types of reproductive surgery performed and underlying reproductive pathologies. The low number of preterm deliveries in the present study might influence the precision of estimations. WIDER IMPLICATIONS OF THE FINDINGS: The present study aims to alter the prevailing opinion that reproductive surgery should only be considered preceding IVF to increase implantation and pregnancy rates after IVF. It implies that in selected infertile women who have had reproductive surgery, a high rate of natural conception, a low rate of multiple pregnancies, and a modest infertility treatment-related effect on preterm delivery should be the reasons to encourage natural conception after reproductive surgery. Furthermore, by allowing for natural conception, we can avoid a high-cost invasive medical procedure. STUDY FUNDING/COMPETING INTEREST(S): The study received no funding. We have no competing interest to declare. TRIAL REGISTRATION NUMBER: N/A.

Perinatal outcome of in vitro fertilization pregnancies in women with polycystic ovary syndrome by pregravid BMI.

OBJECTIVES: Given the adverse effects of either polycystic ovary syndrome (PCOS) or overweight/obesity, one could speculate that patients with both would fare worse than others. We sought to evaluate the relationship between pregravid BMI and pregnancy complications in PCOS patients conceived by assisted reproductive techniques (ART). METHODS: Maternal and fetal/neonatal outcomes of singleton pregnancies after assisted reproduction in women with and without PCOS were compared by pregravid body mass index (BMI, <24.9 vs. ≥25 kg/cm2). RESULTS: The study population comprised 185 with a BMI <24.9 kg/cm2 including 39 (21%) with PCOS and 146 (79%) without. We also included 84 patients with BMI ≥25 kg/cm2, involving 34 (40.5%) with PCOS and 50 (59.5%) without. PCOS (total 73 patients) was significantly more common among overweight/obese patients, OR 2.5 (95% CI 1.4, 4.4). Neonates >4,000 g were born only to the overweight/obese mothers in the PCOS group. A higher incidence of gestational diabetes, chronic hypertension, and gestational hypertension was related to pregravid overweight/obesity rather than PCOS. CONCLUSIONS: In this specific subgroup of patients conceived after assisted reproduction, pregravid BMI>25 kg/cm2 rather than PCOS itself appears to be associated with GDM and hypertensive disorders.

Effect of hysteroscopic septum resection on preterm delivery rate in singleton pregnancies.

INTRODUCTION: Uterine septum is the most common uterine anomaly and is often found during the work-up in primary infertile women. In this study, we aimed to evaluate the potential effect of hysteroscopic septum resection (HSR) on preterm delivery (PTD) in primary infertile women who had singleton pregnancies. MATERIAL AND METHODS: We analyzed 420 singleton pregnancies after primary infertility treatment and compared the PTD rates in women who underwent previous HSR (cases) and women who did not undergo previous operative hysteroscopy or cervical dilation (controls), regardless of the modality of conception (spontaneous or by in vitro fertilization). RESULTS: We did not find significant differences between cases and controls for the incidence of overall PTD rate (p = .237), PTD before 32 gestational weeks (p = .848), and between 32 and 37 gestational weeks (p = .324), premature rupture of membranes (p = .419), and neonatal birth weight (p = .129). Overall, the risk of spontaneous PTD <37 gestational weeks after HSR was not found to be significantly higher compared to controls (RR 1.29, 0.61-2.73 95% CI; p = .561). CONCLUSION: According to our results, previous HSR could be not considered a risk factor for PTD in singleton pregnancies, regardless of the modality of conception (spontaneous or by in vitro fertilization).

Corrigendum to "Is IVF/ICSI an Independent Risk Factor for Spontaneous Preterm Birth in Singletons? A Population-Based Cohort Study".

[This corrects the article DOI: 10.1155/2018/7124362.].

Ambient air pollution and pregnancy outcomes: A comprehensive review and identification of environmental public health challenges.

There is a growing number of studies on the association between ambient air pollution and adverse pregnancy outcomes, but their results have been inconsistent. Consequently, a comprehensive review of this research area is needed. There was a wide variability in studied pregnancy outcomes, observed gestational windows of exposure, observed ambient air pollutants, applied exposure assessment methods and statistical analysis methods Gestational duration, preterm birth, (low) birth weight, and small for gestational age/intrauterine growth restriction were most commonly investigated pregnancy outcomes. Gestational windows of exposure typically included were whole pregnancy period, 1st, 2nd, 3rd trimester, first and last gestational months. Preterm birth was the outcome most extensively studied across various gestational windows, especially at the beginning and at the end of pregnancy. Particulate matter, nitrogen dioxide, ozone, and carbon monoxide were the most commonly used markers of ambient air pollution. Continuous monitoring data were frequently combined with spatially more precisely modelled estimates of exposure. Exposure to particulate matter and ozone over the entire pregnancy was significantly associated with higher risk for preterm birth: the pooled effect estimates were 1.09 (1.03-1.16) per 10 µg/m3 increase in particulate matter with an aerodynamic diameter of 10 µm or less (PM10),1.24 (1.08-1.41) per 10 µg/m3 increase in particulate matter with an aerodynamic diameter of 2.5 µm or less (PM2.5), and 1.03 (1.01-1.04) per 10 ppb increase in ozone. For pregnancy outcomes other than PTB, ranges of observed effect estimates were reported due to smaller number of studies included in each gestational window of exposure. Further research is needed to link the routine pregnancy outcome data with spatially and temporally resolved ambient air pollution data, while adjusting for commonly defined confounders. Methods for assessing exposure to mixtures of pollutants, indoor air pollution exposure, and various other environmental exposures, need to be developed.

Is IVF/ICSI [corrected] an Independent Risk Factor for Spontaneous Preterm Birth in Singletons? A Population-Based Cohort Study.

The aim of our study was to explore the risk factors for very preterm (gestation under 32 weeks) and moderate preterm birth (gestation weeks 32-36 6/7) in singleton pregnancies in a national retrospective cohort study. We also wanted to establish whether IVF/ICSI is an independent risk factor for preterm birth after adjusting for already known confounders. We used data for 267 718 singleton births from 2002-2015 from the National Perinatal Information System of Slovenia, containing data on woman, pregnancy, birth, the postpartum period, and the neonate for each mother-infant pair. Mode of conception, maternal age, education, BMI, parity, smoking, history of cervical excision procedure, history of hysteroscopic resection of uterine septum, presence of other congenital uterine malformations, bleeding in pregnancy, preeclampsia or HELLP and maternal heart, and pulmonary or renal illness were included in the analyses. Unadjusted OR for very preterm birth after IVF-ICSI [corrected] was 2.8 and for moderate preterm birth was 1.7. After adjusting for known confounders, the OR was still significantly elevated (1.6 and 1.3, respectively). Risk factors for very preterm birth with OR higher than 2.4 were history of cervical excision procedure, resection of uterine septum, operation or having other congenital uterine malformations, and bleeding in pregnancy. Risk factors for very preterm birth with OR between 1.4 and 2.1 were age >35 years, being underweight or obese, not having professional education, smoking, first birth, preeclampsia/HELLP, and IVF/ICSI. Risk factors for moderate preterm birth with OR higher than 2.4 were history of cold knife conization and other congenital uterine malformations. We found that even after adjustment, IVF/ICSI represents a single risk factor for early and late preterm birth even after adjustment with other risks such as maternal age, smoking, or a history of invasive procedures for either cervical intraepithelial neoplasia or infertility treatment.

Spontaneous pregnancy rates after reproductive surgery.

With the development of IVF procedures, the role of reproductive surgery in the management of infertile couples has been questioned. Pregnancy rates (PR) after IVF procedures are well known, but recent data on spontaneous PR after reproductive surgery are scarce. This study aimed to prospectively evaluate how often fertility is restored by reproductive surgery and to identify which independent factors influence spontaneous pregnancy after reproductive surgery. Eight hundred eighty-eight infertile women who underwent surgery for infertility were prospectively included. Women who were referred to IVF after surgery, ceased to plan pregnancy and were lost to follow-up were excluded. Spontaneous PR was analysed for 519 women. A total of 252 (48.6%) women, including 30 treated with clomiphene citrate, conceived spontaneously in the 12-18 months observation period following surgery. Multivariate logistic regression showed that woman's age (OR 0.95, 95% CI 0.90-0.99) and duration of infertility (OR 0.86, 95% CI 0.74-0.99) significantly influence spontaneous PR. Each year of infertility lowers spontaneous PR following surgery by 14% and each year of woman's age by 5%. The study shows a relatively high percentage of women conceived spontaneously after reproductive surgery. The role of reproductive surgery in the management of infertility should be re-evaluated.

Independent factors influencing large-for-gestation birth weight in singletons born after in vitro fertilization.

PURPOSE: Higher risk for birth of singletons being large for gestational age (LGA) has been revealed after in vitro fertilization (IVF) frozen-thawed embryo-transfer (FET). This phenomenon is now being investigated, since there is a speculation that these neonates could suffer from underlying epigenetic disturbances. The aim of the study was to expose independent LGA risk factors and to identify those connected to the IVF techniques. METHODS: Altogether, 4508 singleton pregnancies and births were included in the cohort case-matched study. Two hundred eleven singleton pregnancies and births after FET and 916 after fresh embryo transfer (ET) were included into two study groups. The IVF procedures were performed at the University Medical Centre Ljubljana between 2004 and 2011. For each IVF pregnancy, three matched consecutive controls after natural conception were included. Using logistic regression models, we observed LGA connection to maternal parameters (smoking, hypertension, parity, BMI, gestational diabetes, IVF conception, FET, double ET, and ICSI procedure). RESULTS: Singletons born after FET had a significantly higher risk for being LGA (p = 0.032; OR 1.697; 95 % CI 1.047-2.752). BMI 25-30 was a significant independent risk factor for LGA in the IVF groups (FET p = 0.041, OR 2.460, 95 % CI 1.030-5.857 and fresh ET p = 0.003; OR 2.188, 95 % CI 1.297-3.691). ICSI and double ET had no significant effect on LGA occurrence. CONCLUSIONS: Besides maternal BMI, FET is a significant independent LGA risk factor in IVF patients. Other observed factors (smoking, hypertension, multiparity, GDM, ICSI procedure, or number of embryos transferred) do not influence LGA risk significantly.

Singleton pregnancy outcomes after in vitro fertilization with fresh or frozen-thawed embryo transfer and incidence of placenta praevia.

The aim of the study was to compare the single pregnancy and neonate outcome after fresh and frozen-thawed embryo transfer in the in vitro fertilization programme (IVF). The study focused on clinical and laboratory factors affecting the abnormal placentation, especially placenta praevia, in patients conceiving in the IVF programme. The results confirm that neonates born after frozen-thawed embryo transfer had significantly higher mean birth weight than after fresh embryo transfer (ET). Moreover, the birth weight distribution in singletons was found to shift towards "large for gestation" (LGA) after frozen-thawed ET. On the other hand, the pregnancies after fresh ET were characterized by a higher incidence of placenta praevia and 3rd trimester bleeding. Placenta praevia was more common in IVF patients with fresh ET in a stimulated cycle than in patients with ET in a spontaneous cycle. It occurred more frequently in patients with transfer of 2 embryos. From this point of view, single ET and ET in a spontaneous cycle should be encouraged in good prognosis patients in the future with more than two good quality embryos developed. An important issue arose of how the ovarian hormonal stimulation relates to abnormal placentation and if the serum hormone levels interfere with in the IVF treatment results.

Preterm delivery risk factors in singletons born after in vitro fertilization procedures.

OBJECTIVES: Women delivering singletons after in vitro fertilization (IVF) procedures have a greater risk of preterm delivery (PD). The aim of our study was to analyze PD risk factors and to identify those that could possibly be prevented. STUDY DESIGN: In our matched controlled study we analyzed 1127 singleton deliveries after IVF and transfer of fresh embryos performed at the University Medical Center Ljubljana between 1 January 2002 and 31 December 2010. For every delivery included in the study group we chose three consecutive controls matched by maternal age, parity and maternity hospital. The main outcome measure was PD (<37 weeks). Investigated variables were: previous PD (PPD), conization, pregestational diabetes mellitus, uterine anomaly, operation on the uterus, chronic renal disease, maternal age and parity, and body mass index (BMI). Variables investigated within the IVF group were: stimulation protocol, laboratory procedure, number of retrieved oocytes and number and quality of transferred embryos. RESULTS: The PD rate after IVF was 1.5 times higher than after natural conception (11.5% in the IVF group and 7.7% in the control group, p<0.001). Conization and chronic renal disease were shown to be significant risk factors for PD in both the IVF group and the naturally conceiving controls. BMI>30 was an important risk factor only in the IVF group (OR 1.86 (1.06-3.27) vs. 1.10 (0.67-1.80)) and PPD only in the controls (OR 1.83 (0.78-4.28) vs. 3.22 (1.55-6.67)). Among the investigated PD risk factors, an IVF procedure was shown to be the fifth most important one. On analyzing parameters of the ovarian stimulation and IVF procedure, no PD risk factor was identified. CONCLUSIONS: IVF was shown to be a significant risk factor for PD. In the IVF population, BMI plays a far more important role in PD than in the fertile population. In our research PD reoccurrence in IVF group was less than expected, which could perhaps be explained by the surgical correction of gynecological pathology and, where necessary, its being combined with cerclage. The investigation of parameters related to the IVF procedure did not identify any risk factors for PD.

Single fresh and frozen-thawed blastocyst transfer using hyaluronan-rich transfer medium.

The purpose of this prospective randomized study was to evaluate use of a hyaluronan-rich transfer medium in fresh and frozen-thawed single blastocyst transfer. The study included 279 single blastocyst transfers in women aged<37 years in their first, second or third treatment cycle. According to the type of single blastocyst transfer (fresh elective or frozen-thawed) the women were divided into two study and two control groups. In both study groups (n=130) transfers were performed using hyaluronan and in the control groups (n=149) a conventional transfer medium was used. The results indicate that fresh elective single blastocyst transfer with hyaluronan results in significantly higher pregnancy rates in a selected subgroup of women; those with >or=2 blastocysts developed to day 5 and a previous implantation failure (55% versus 10%; P=0.012). Overall pregnancy rates after fresh elective and frozen-thawed single blastocyst transfer were similar in both study and control groups.