P–329 Müllerian anomalies and embryo implantation in oocyte donation

Study question

Do patients with Mullerian anomalies (MA) who receive donated oocytes have different embryo implantation rate than patients with normal uterus?

Summary answer

In oocyte donation, patients with MA had lower implantation rate than patients with normal uterus.

What is known already

MA are associated with infertility and miscarriage but the mechanisms to explain this relation are not known. Some studies describe both oocyte and/or uterine factor. All studies describing the outcome in patients with MA, so far, are with own oocytes but none in oocyte donation.

Study design, size, duration

A multicentre restrospective cohort study from January 2000 to December 2019. Patients receiving donated oocytes were divided between those with MA (n = 473) according ESHRE classification and other group with normal uterus (n = 57 869). The primary outcome was implantation rate at fresh embryo transfer. Secondary aims were biochemical pregnancy rate, clinical pregnancy rate, ongoing pregnancy rate, miscarriage rate and live pregnancy rate.

Participants/materials, setting, methods

We considered the first oocyte donation cycle, without severe male factor, myomas, hydrosalpinx, Asherman syndrome, polyps or indication for preimplantational genetic diagnosis divided in two groups; patients with MA and no malformed uterus. MA group includes cycles of complete bicorporeal uterus (162), partial bicorporeal (30), bicorporeal septate (15), T shaped uterus (26), infantilis uterus (8), complete septate uterus (110), partial septate uterus (94) and hemi-uterus without rudimentary cavity (29).

Main results and the role of chance

We registered 58 342 patients from our oocyte donation program. Results are shown as mean and 95%CI and differences in pregnancy rates were expressed as relative risks (RR) with 95% CI being reference patients with normal uterus. In patients with MA, the implantation rate was different according the categories being significantly lower in patients with unicornuate uterus (0.29 95%CI: 0.14–0.43. p = 0.03). Biochemical pregnancy rate was significantly higher in patients with septate uterus (RR 1.51 (95%CI 1.02–2.22, p = 0.03) and significantly lower in unicornuate uterus (RR 0.49 (95%CI 0.27–0.90). No differences were found in clinical pregnancy rate among groups, but ongoing pregnancy rate and live birth rate were lower in unicornuate uterus ( RR 0.28 (95%CI 0.13–0.63, p = 0.002), (RR 0.32 (95%CI 0.14–0.73, p = 0.007) respectively. Miscarriage rate was significantly higher in patients with septate uterus (RR 1.78 (95%CI 1.18–2.68, p = 0.006)

Limitations, reasons for caution

As this was a retrospective cohort study, we were unable to study differences due to modifications in medical or laboratory protocols during this long period time. Different size of sample in some groups of MA makes impossible to translate conclusions to general population.

Wider implications of the findings: Our results indicate that there might be a defect in the embryo implantation rate in patients with MA depending on uterine factor. Different sample size among groups and some groups with scarce number of cases make less precise results. More studies controlling biases are needed to confirm our results.

Trial registration number

NCT04571671

Hyperthyroidism and production of precocious involution in the mammary glands of lactating rats

This study investigated the influence of chronic hyperthyroidism on mammary function in lactating rats and the effects on their pups. Thyroxine-treated (10 microg per 100 g body weight per day; hyperthyroid (HT)) or vehicle-treated rats were mated 2 weeks after the start of treatment and killed with their litters on days 7, 14 and 21 of lactation. Serum concentrations of triiodothyronine (T(3)) and tetraiodothyronine (T(4)) increased in thyroxine-treated rats. In HT mothers, serum prolactin decreased on day 7 and day 14 of lactation, whereas insulin-like growth factor I (IGF-I) and progesterone concentrations decreased, and corticosterone increased on day 7 of lactation. In HT pups, T(4) concentration increased on day 7 and day 14 of lactation, whereas T(3) increased only on day 14 of lactation, and growth hormone increased on day 7 of lactation. Mammary prolactin binding sites did not vary, but there was an increase in the binding sites in the liver on day 14 of lactation in thyroxine-treated rats. In an acute suckling experiment, thyroxine-treated rats released less oxytocin, growth hormone and prolactin and excreted less milk than did control rats. Mammary casein, lactose and total lipid concentrations in thyroxine-treated rats were similar to those of control rats on day 14 of lactation. Histological studies of the mammary glands showed an increased proportion of alveoli showing reduced or no lumina and cells with condensed nuclei on day 14 and day 21 of lactation; the TdT-mediated dUTP nick-end labelling (TUNEL) test revealed an increase in apoptosis in alveolar cells on day 21 of lactation in thyroxine-treated rats. Expression of SGP-2, a gene expressed during mammary involution, increased in thyroxine-treated rats on day 14 and day 21 of lactation, whereas expression of insulin-like growth factor binding protein 5, a proapoptotic signal, was unchanged. Bcl-2, which promotes survival of mammary gland epithelial cells was unchanged, whereas expression of IGF-I, which also promotes survival of mammary gland epithelial cells, increased on day 21 of lactation in thyroxine-treated rats. These results indicate that thyroxine treatment produces some milk stasis as a result of impairments in suckling induced release of oxytocin that may initiate the first stage of mammary involution, increasing apoptosis in a gland that is otherwise actively producing and secreting milk.

Ultrastructural and morphometric study of the Sertoli cell of the viscacha (Lagostomus maximus maximus) during the annual reproductive cycle

Changes in the morphology of viscacha Sertoli cells were studied during the annual reproductive cycle. Sertoli cells exhibited marked nuclear and cytoplasmic changes. Seasonal variation in nuclear size and shape, chromatin texture, and nucleolus characteristics was observed. The seasonal patterns of the volume densities of the endoplasmic reticulum (ER), mitochondria, Golgi complex, dense bodies and lipid inclusions were distinct. Morphometric analysis revealed that the Golgi complex is the organelle most sensitive to seasonal change. It declined drastically in the regressed testes and its recovery was slow. The ER and mitochondria exhibited seasonal variations in their pattern and content, that was minimal during winter. In contrast, an accumulation of lipid and dense bodies, such as primary and secondary lysosomes, accompanied the spermatogenic arrest. The volume densities of both organelles were maximum during the restoration of spermatogenesis. The length and organization of the inter-Sertoli junctions also changed with the reproductive cycle. The Sertoli cell number per tubular cross section decreased significantly during the testicular regression, coincident with the presence of Sertoli cells with marked signs of involution. The degree of regression and recovery exhibited by the viscacha Sertoli cells was closely related to that shown by the associated germ cells. Therefore, seasonal endocrine fluctuations and local factors could be involved in the regulation of the morphological and functional characteristics of the viscacha Sertoli cells. These hormonal fluctuations are synchronized by the photoperiod through the pineal gland and its hormone, melatonin.

Stages of the cycle of the seminiferous epithelium of the viscacha (Lagostomus maximus maximus)

The adult male viscacha (Lagostomus maximus maximus) is a seasonal rodent. It exhibits a short period of testicular regression with partial arrest of spermatogenesis during winter (July-August). The present study provides the first description of the viscacha spermatogenic cycle during the period of maximum gonadal activity (summer-autumn). The testes were processed by using conventional techniques of light and electron microscopy. One-micrometer-thick sections stained with toluidine blue were used to clearly define the different cell associations. Spermatogenesis in this rodent is well organized and synchronized and has been divided into nine stages. The present classification is based on the morphogenesis of the acrosomal system (stages I-V) and the degree of elongation and condensation of the heads of the differentiating spermatids (stages VI-IX). Stage I is principally defined by round spermatids with a well-developed, juxtanuclear Golgi complex and without acrosomal components that are visible under the light microscope. Sperm release from the viscacha seminiferous epithelium occurs either in late stage III or in early stage IV. Stage IX is characterized by diplotene spermatocytes, figures of meiosis I or II, and secondary spermatocytes.