Recent in vitro and in vivo experimental evidence supports a role of vitamin D insufficiency as an important factor in the development of uterine leiomyomas. However, epidemiological data supporting this possibility are scanty. Our objective was to investigate vitamin D status in women with and without uterine leiomyomas. This was a case-control study of women referring to 2 infertility units in Italy. Women were eligible as cases if they were diagnosed with at least 1 uterine leiomyoma with a mean diameter ≥10 mm at transvaginal ultrasound. Each of them was matched to the 2 subsequent women of the same age (±1 year) whose uterus resulted unremarkable at ultrasound. Selected women provided a blood sample for the quantitative detection of 25-hydroxyvitamin D₃ levels. We measured serum concentration of 25-hydroxyvitamin D₃. A total of 128 women with leiomyomas and 256 controls were selected. The mean ± SD serum concentration of 25-hydroxyvitamin D3 was significantly lower in affected women compared with controls (18.0 ± 7.7 vs 20.8 ± 11.1 ng/mL respectively, P = .010). The number (proportion) of women with 25-hydroxyvitamin D3 deficiency (ie, <10 ng/mL) in cases and controls was 19 (15%) and 19 (7%), respectively (P = .022). The adjusted odds ratio for the presence of leiomyomas in women with serum levels of 25-hydroxyvitamin D₃ deficiency was 2.4 (95% confidence interval = 1.2-4.9) (P = .016). Vitamin D is an emerging regulator of uterine leiomyoma development. Cohort and interventional studies are pressingly needed to confirm a causal relationship and to investigate the potential therapeutic benefits of vitamin D supplementation.

Vitamin D deficiency has been proven to affect fertility in mammals, but data in human is less convincing. In particular, data on in vitro fertilization (IVF), an attractive model to draw information on this topic, are sparse and conflicting. Our objective was to investigate IVF outcome in women with deficient 25-hydroxy-vitamin D [25(OH)D] serum levels (30 ng/mL) had the highest chances of pregnancy. Vitamin D is an emerging factor influencing female fertility and IVF outcome. Additional studies are pressingly needed to confirm a causal relationship and to investigate the potential therapeutic benefits of vitamin D supplementation.

Cycles with progesterone elevation during controlled ovarian stimulation (COS) for IVF/ICSI are commonly managed with a “freeze-all” strategy, due to a well-recognized detrimental effect of high progesterone levels on endometrial receptivity. However, also a detrimental effect of elevated progesterone on day-3 embryo quality has recently been found with regards to top quality embryo formation rate. Because blastocyst culture and cryopreservation are largely adopted, we deemed relevant to determine whether this detrimental effect is also seen on blastocyst quality on day 5–6. This issue was investigated through a large two-center retrospective study including 986 GnRH antagonist IVF/ICSI cycles and using top quality blastocyst formation rate as the main outcome. Results showed that on multivariate analysis sperm motility (p1.49 ng/ml as the best cut-off for identification of patients at risk for the absence of top quality blastocysts (AUC 0.55, p<0.01). Our study is the first to investigate the top quality blastocyst formation rate in relation to progesterone levels in IVF/ICSI cycles, showing that increasing progesterone is associated with lower rates of top quality blastocyst. Hence, the advantages of prolonging COS to maximize the number of collected oocytes might eventually be hindered by a decrease in top quality blastocysts available for transfer, if increasing progesterone levels are observed. This observation extends the results of two recent studies focused on day-3 embryos and deserves further research.

A diagnosis of unexplained infertility is commonly made when clinical investigations fail to identify any obvious barriers to conception. As a consequence, unexplained infertility includes several heterogeneous conditions, one being women with age-related infertility. However, the latter represent a peculiar and different situation. Women with age-related infertility may have a different prognosis and may benefit from different treatments. Unfortunately, since fecundity declines with age, discerning between unexplained infertility and age-related infertility becomes more and more difficult as the woman's age increases. In this opinion, with the use of a mathematical model we show that the rate of false positive diagnoses of unexplained infertility increases rapidly after 35 years of age. Using a threshold of 2 years of unfruitful, regular unprotected intercourse, this rate exceeds 50% in women starting pregnancy seeking after 37 years. The scenario is much worse using a threshold of 1 year. From a clinical perspective, extrapolating results obtained in a population of young women with unexplained infertility to those with age-related infertility is not justified. It is noteworthy that, if Assisted Reproductive Technologies are unable to overcome age-related infertility, the older women erroneously labeled with unexplained infertility may receive inappropriate therapies. These may expose women to unjustified risks and waste financial resources. Unfortunately, the available literature about older women is scanty and does not provide valid evidence. Randomized controlled trials aimed at identifying the most suitable clinical management of older women with a normal infertility work-up are pressingly needed.

STUDY QUESTION Are women with endometriosis who conceive with IVF at increased risk of preterm birth? SUMMARY ANSWER Women with endometriosis who conceive with IVF do not face an increased risk of preterm birth. WHAT IS KNOWN ALREADY The eutopic endometrium of women with endometriosis has been repeatedly shown to present molecular and cellular alterations. On this basis, it has been hypothesized that pregnancy outcome may be altered in affected women. However, to date, available evidence from epidemiological studies is scanty and conflicting. Data tended to be partly consistent only for an increased risk of preterm birth and placenta previa. STUDY DESIGN, SIZE, DURATION Retrospective matched case–control study of women achieving an IVF singleton pregnancy progressing beyond 12 weeks’ gestation. PARTICIPANTS/MATERIALS, SETTING, METHODS Women achieving IVF singleton pregnancies that progressed beyond 12 weeks' gestation at two infertility units were reviewed. Cases were women with a history of surgery for endometriosis and/or with a sonographic diagnosis of the disease at the time of the IVF cycle. Controls were women without current or past evidence of endometriosis who were matched to cases by age (± 6 months), type of cycle (fresh or frozen cycle) and study period. Male factor and unexplained infertility were the most common diagnoses in the control group. Two hundred and thirty-nine women with endometriosis and 239 controls were selected. The main outcome of the study was the rate of preterm birth (birth < 37 weeks' gestation) regardless of the cause. Secondary analyses were performed for the most common obstetrical complications. MAIN RESULTS AND THE ROLE OF CHANCE The rate of preterm birth was similar in the two study groups (14% and 14%, respectively, p = 0.89). The rate of live birth and the incidence of hypertensive disorders, gestational diabetes, small and large for gestational age newborns and neonatal problems also did not differ. In contrast, placenta previa was more common in women with endometriosis than controls (6% versus 1%, respectively; p = 0.006): The adjusted odds ratio was 4.8 (95% confidence interval: 1.4–17.2). LIMITATIONS, REASONS FOR CAUTION As for all observational studies, confounders cannot be totally excluded. Moreover, the retrospective study design exposes the findings to some inaccuracies. For example, the independent role of adenomyosis could not be reliably assessed because this diagnosis is complex and would necessitate a prospective recruitment. Second, the selection of controls may also be a matter of concern because some affected women may have been erroneously included in this group. Third, even if the sample size is significant, it is insufficient for robust subgroup analyses. Finally, it is mandatory to point out that our conclusions are valid for IVF pregnancies only, and specific data from properly designed studies are required to support any inference for natural pregnancies. WIDER IMPLICATIONS OF THE FINDINGS The results of our study suggest that women with endometriosis conceiving with IVF can be reassured regarding the risk of preterm birth. The observed association with placenta previa requires further investigation and may open a new avenue of research. STUDY FUNDING/COMPETING INTEREST(s) No external funding was used for this study. None of the authors have any conflict of interest to declare.