Effects of photoevaporation on protoplanetary disc ‘isochrones’

Protoplanetary discs are the site of star and planet formation, and their evolution and consequent dispersal deeply affect the formation of planetary systems. In the standard scenario they evolve on time-scales similar to Myr due to the viscous transport of angular momentum. The analytical self-similar solution for their evolution predicts specific disc isochrones in the accretion rate-disc mass plane. However, photoevaporation by radiation emitted by the central star is likely to dominate the gas disc dispersal of the innermost region, introducing another (shorter) time-scale for this process. In this paper, we include the effect of internal (X and EUV) photoevaporation on the disc evolution, finding numerical solutions for a population of protoplanetary discs. Our models naturally reproduce the expected quick dispersal of the inner region of discs when their accretion rates match the rate of photoevaporative mass loss, in line with previous studies. We find that photoevaporation preferentially removes the lightest discs in the sample. The net result is that, counter-intuitively, photoevaporation increases the average disc mass in the sample, by dispersing the lightest discs. At the same time, photoevaporation also reduces the mass accretion rate by cutting the supply of material from the outer to the inner disc. In a purely viscous framework, this would be interpreted as the result of a longer viscous evolution, leading to an overestimate of the disc age. Our results thus show that photoevaporation is a necessary ingredient to include when interpreting observations of large disc samples with measured mass accretion rates and disc masses. Photoevaporation leaves a characteristic imprint on the shape of the isochrone. Accurate data of the accretion rate-disc mass plane in the low disc mass region therefore give clues on the typical photoevaporation rate

Risk factors for monozygotic twinning after in vitro fertilization : a systematic review and meta-analysis

Objectives: To establish the risk factors for monozygotic twin (MZT) and monochorionic twin (MCT) pregnancies after in vitro fertilization (IVF). Design: Systematic review and meta-analysis. Setting: Not applicable. Patient(s): Women who achieved MZT and non-MZT pregnancies through IVF. Intervention(s): Systematic search of Medline from January 1995 to October 2018 with cross-checking of references from relevant articles in English. Main Outcome Measure(s): Possible risk factors for MZT or MCT pregnancies after IVF, comprising extended embryo culture, insemination method (conventional IVF and intracytoplasmic sperm injection [ICSI]), embryo biopsy for preimplantation genetic testing for aneuploidies or for monogenic/single-gene defects (PGT-A or PGT-M) programs, assisted hatching (AH), oocytes donation, female age, and embryo cryopreservation. Result(s): A total of 40 studies were included. Blastocyst transfer compared with cleavage-stage embryo transfer, and female age <35 years were associated with a statistically significant increase in the MZT and MCT pregnancy rate after IVF: (23 studies, OR 2.16, 95% CI, 1.74\u20132.68, I 2 =78%; 4 studies, OR 1.29; 95% CI, 1.03\u20131.62, I 2 =62%; and 3 studies, OR 1.90, 95% CI, 1.21\u20132.98, I 2 =59%; 2 studies, OR 2.34; 95% CI, 1.69\u20133.23, I 2 =0, respectively). Conventional IVF compared with ICSI and assisted hatching were associated with a statistically significantly increased risk of MZT pregnancy (9 studies, OR 1.19, 95% CI, 1.04\u20131.35, I 2 =0; 16 studies, OR 1.17, 95% CI, 1.09\u20131.27, I 2 =29%, respectively). Embryo biopsy for PGT-A or PGT-M, embryo cryopreservation, and oocytes donation were not associated with MZT pregnancies after IVF. Conclusion(s): Blastocyst transfer is associated with an increased risk of both MZT and MCT pregnancies after IVF. Further evidence is needed to clarify the impact of female age, insemination method and AH on the investigated outcomes

Ovarian stimulation and endometriosis progression or recurrence: a systematic review

Available evidence on the impact of ovarian stimulation on the progression of endometriosis or its recurrence was systematically reviewed. Data from ovarian stimulation alone, or associated with intrauterine insemination (IUI) or IVF, were included. Sixteen studies were selected. Initial case reports (n = 11) documented some severe clinical complications. However, subsequent observational studies were more reassuring. Overall, five conclusions can be drawn: (i) IVF does not worsen endometriosis-related pain symptoms (moderate quality evidence); (ii) IVF does not increase the risk of endometriosis recurrence (moderate quality evidence); (iii) the impact of IVF on ovarian endometriomas, if present at all, is mild (low quality evidence); (iv) IUI may increase the risk of endometriosis recurrence (low quality evidence); (v) deep invasive endometriosis might progress with ovarian stimulation (very low quality evidence). In conclusion, available evidence is generally reassuring (at least for IVF) and does not justify aggressive clinical approaches such as prophylactic surgery before assisted reproductive technology treatment to prevent endometriosis progression or recurrence. However, further evidence is required before being able to reach definitive conclusions. In particular, the potential effects on deep invasive endometriosis and the possible synergistic effect of stimulation and pregnancy are two areas that need to be explored further

Medical treatment of endometriosis-related pain

Available medical treatments for symptomatic endometriosis act by inhibiting ovulation, reducing serum oestradiol levels, and suppressing uterine blood flows. To this aim, several drugs can be used, with a similar magnitude of effect, in term of pain relief, independently of the mechanism of action. Conversely, safety, tolerability, and cost differ. Medications for endometriosis can be categorised into low-cost drugs, including OCs and most progestogens, and high cost drugs, including dienogest and GnRH agonists. As the individual response to different drugs is variable, a stepwise approach is suggested, starting with OCs or low-cost progestogens, and stepping up to high-cost drugs only in case of inefficacy or intolerance. Oral contraceptives may be used in women with dysmenorrhoea as their main complaint, and when only superficial peritoneal implants or ovarian endometriomas < 5 cm are present, while progestogens should be preferred in women with severe deep dyspareunia and when infiltrating lesions are identified

Time to redefine endometriosis including its pro-fibrotic nature

Endometriosis is currently defined as presence of endometrial epithelial and stromal cells at ectopic sites. This simple and straightforward definition has served us well since its original introduction. However, with advances in disease knowledge, endometrial stromal and glands have been shown to represent only a minor component of endometriotic lesions and they are often absent in some disease forms. In rectovaginal nodules, the glandular epithelium is often not surrounded by stroma and frequently no epithelium can be identified in the wall of ovarian endometriomas. On the other hand, a smooth muscle component and fibrosis represent consistent features of all disease forms. Based on these observations, we believe that the definition of endometriosis should be reconsidered and reworded as 'A fibrotic condition in which endometrial stroma and epithelium can be identified'. The main reasons for this change are: (1) to foster the evaluation of fibrosis in studies on endometriosis pathogenesis using animal models; (2) to limit potential false negative diagnoses if pathologists stick stringently to the current definition of endometriosis requiring the demonstration of endometrial stromal and glands; (3) to consider fibrosis as a potential target for treatment in endometriosis. This opinion article is aimed at boosting the attention paid to a largely neglected aspect of the disease. We hope that targeting the fibrotic process might increase success in developing new therapeutic approaches

Forever Young:Testosterone replacement therapy: a blockbuster drug despite flabby evidence and broken promises

In the last decade, testosterone replacement therapy (TRT) has been increasingly prescribed to treat a controversial condition known as 'late-onset hypogonadism (LOH)'. This syndrome is diagnosed in men who, for no discernible reason other than older age, obesity or ill health have serum testosterone concentrations below the normal range for healthy young men and report one or more of the following symptoms: muscle weakness or wasting, mood, behaviour and cognition-related symptoms and sexual function or libido impairment. However, recent evidence has demonstrated that testosterone drugs do not substantially ameliorate these symptoms and, more worryingly, that their long-term use may be associated with severe adverse effects (i.e. increased risk of prostate cancer, stroke and myocardial infarction, worsening of benign prostatic hyperplasia symptoms and testicular atrophy). Nonetheless, testosterone drugs have exhibited extraordinary commercial success and their pharmaceutical sales are steadily rising. Behind this apparently unjustifiable trend there are deliberate, well designed direct and indirect pharmaceutical marketing initiatives that exploit the conviction rooted in contemporary society that testosterone can reverse the effects of ageing and ensure social accomplishment. Commercial mechanisms have laid the foundation for disease mongering of LOH and also have resulted a considerable expansion of the indications for treatment. This promotion model deserves particular attention since it is applicable to any drug with a purportedly favourable risk-benefit ratio not supported by evidence

The Rapid Growth of Fibroids during Early Pregnancy

Several studies aimed to disentangle whether pregnancy influences the growth of uterine fibroids but results were inconsistent. In this study, we speculated that fibroid enlargement during pregnancy may not be linear and we hypothesized that this phenomenon may mainly occur during initial pregnancy. To test this hypothesis, we set up a prospective cohort study of women with fibroids undergoing IVF. Cases were women achieving a viable pregnancy. Controls were the subsequent women with fibroids but failing to become pregnant. Twenty-five cases and 25 controls were recruited. The total number of fibroids in the two groups was 46 and 41, respectively. The mean \ub1 SD diameter of the fibroids was 17 \ub1 10 and 20 \ub1 11 mm, respectively (p = 0.18). A statistically significant enlargement emerged exclusively in pregnant women. The median (Interquartile Range) modification of the diameter of the lesions in cases and controls was +34% (+6%/+65%) and +2% (-6%/+12%), respectively (p&lt;0.001). The median (Interquartile Range) modification of the volume of the lesions was +140% (+23%/+357%) and 0% (-18%/+37%), respectively (p&lt;0.001). In pregnant women, we failed to document any significant correlation between the magnitude of the growth and ovarian responsiveness to hyper-stimulation, suggesting that steroids hormones are not the unique factors involved. In conclusion, fibroids undergo a rapid and remarkable growth during initial pregnancy. Reasons behind this phenomenon remain to be clarified. The early rise in steroids hormones during early pregnancy may not be sufficient to explain the process. Other pregnancy-related hormones and proteins may play also key roles

The impact of IVF on deep invasive endometriosis

Objective: Ovarian hyper-stimulation during IVF is associated with a significant raise in serum estrogens and one may expect detrimental effects on estrogen-dependent diseases such as endometriosis. However, available evidence from large case series of affected women performing IVF is generally reassuring with the possible exception of women carrying deep invasive lesions. On this basis we deemed important investigating more in depth whether women with deep invasive endometriosis could be a subgroup at higher risk of recurrence or disease progression during IVF. Study design: Women with endometriosis who underwent IVF and who had a second evaluation after 3\u20136 months from a failed cycle were retrospectively reviewed. The main inclusion criteria were the presence of deep invasive endometriosis and/or a history of surgery for this form of the disease. The primary aim of the study was to determine the frequency of endometriosis-related complications in the interval between the two evaluations. Secondary aims were pain symptoms and lesion size modifications. Results: Eighty-four women were ultimately selected: baseline ultrasound documented deep invasive lesions in 60 of them. One case of possible endometriosis-related complication was recorded, corresponding to a rate of 1.2% (95%: 0.05%\u20135.5%) for the whole cohort and 1.7% (95%CI: 0.08\u20137.6%) for the subgroup of women with ultrasound detected lesions. This rate appears similar to the reported frequency of endometriosis progression in women not receiving IVF. No significant modifications in pain symptoms or lesions size occurred. Conclusions: Women with deep invasive endometriosis who underwent IVF do not seem to be exposed to a substantially increased risk of recurrence/disease progression. Larger evidence from independent groups is however required for a definitive conclusion

The presence of dominant follicles and corpora lutea does not perturb response to controlled ovarian stimulation in random start protocols

The advent of random start protocols to shorten the time needed to store oocytes in women with malignancies has represented an important improvement in the field of fertility preservation. However, Randomized Controlled Trials are difficult to implement in this area and available evidence that supports this approach remains modest. To shed more light on this issue, we compared the follicular development between the ovary carrying the dominant follicle or the corpus luteum and the contralateral resting ovary in 90 women who underwent random start controlled ovarian stimulation (COS). In fact, ovarian response did not differ between the two ovaries. Subgroup analyses according to the phase of the cycle at the initiation of COS, the type of malignancy, the use of letrozole and the magnitude of the ovarian response did not allow to identify any condition showing a difference in the follicular response between the active and the resting ovaries. In conclusion, follicular growth does not seem to be perturbed by the presence of a dominant follicle or a corpus luteum