Birth weight for gestational age and the risk of infertility: a Danish cohort study.

STUDY QUESTION: Is birth weight for gestational age associated with infertility in adulthood among men and women? SUMMARY ANSWER: Being born small for gestational age (SGA) was associated with infertility in adulthood among men. WHAT IS KNOWN ALREADY: Fetal growth restriction may affect fertility, but results from previous studies have been inconsistent. STUDY DESIGN, SIZE, DURATION: In this population-based cohort study, we used data from a Danish birth cohort, including 5594 men and 5342 women born between 1984 and 1987. Information on infertility was obtained from Danish health registers during the period from the participants' 18th birthday and up until 31 December 2017. PARTICIPANTS/MATERIALS, SETTING, METHODS: Participants were men and women born in two Danish municipalities, Aalborg and Odense. Information on birth weight and gestational age was obtained from birth records, and information on infertility diagnoses and fertility treatment was retrieved from the Danish National Patient Registry (NPR) and the Danish In Vitro Fertilisation (IVF) registry. Information on potential maternal confounders was obtained from questionnaires during pregnancy and was included in adjusted analyses. Logistic regression analysis was used to estimate crude and adjusted odds ratios (ORs) with 95% confidence intervals (CIs) for infertility according to birth weight for gestational age. MAIN RESULTS AND THE ROLE OF CHANCE: Men born SGA had a 55% higher risk of being diagnosed with or treated for infertility compared to men born appropriate for gestational age (AGA) (adjusted OR = 1.55, 95% CI: 1.09-2.21). The association attenuated after exclusion of men born with hypospadias or cryptorchidism (OR = 1.37, 95% CI: 0.93-2.01). No association was found between women's birth weight for gestational age and risk of infertility (adjusted OR = 1.00, 95% CI: 0.73-1.37). LIMITATIONS, REASONS FOR CAUTION: Estimation of gestational age is associated with some uncertainty and might have caused non-differential misclassification. The study design implicitly assumed similar distribution of reproductive and health-seeking behaviour across the groups that were compared. WIDER IMPLICATIONS OF THE FINDINGS: Men born SGA had a higher risk of infertility. Genital malformations may account for part of the observed association, but this must be explored further. STUDY FUNDING/COMPETING INTEREST(S): This study was supported by Health, Aarhus University. No competing interests are declared. TRIAL REGISTRATION NUMBER: N/A.

Oral contraceptive use and genital anomalies in sons. A Danish cohort study.

Exposure to exogenous sex hormones with estrogenic or anti-androgen properties may influence intrauterine development of male genitals. This population-based cohort study based on data from 44,408 live-born singleton sons in the Danish National Birth Cohort (DNBC) aimed to investigate whether maternal use of oral contraceptives prior to or during early pregnancy increase the risk of cryptorchidism or hypospadias. We found no consistent association between use of oral contraceptives and cryptorchidism or hypospadias, neither in those exposed any time four months prior to conception [cryptorchidism: adjusted Odds Ratio (aOR): 1.06 (95% CI: 0.91; 1.23), hypospadias: 0.74 (95% CI: 0.53; 1.03)] nor in those exposed any time during the first trimester of pregnancy [cryptorchidism: aOR: 0.93 (95% CI: 0.53; 1.62), hypospadias: 1.02 (95% CI: 0.32; 3.23)]. Despite relatively strong exposure levels from oral contraceptive use in pregnancy, this study revealed no evidence of an increased risk of either two genital malformations.

Femoral osteochondroplasty can be performed effectively without the risk of avascular necrosis or femoral neck fractures in an experimental ovine FAI model.

OBJECTIVE: The experimental induction of cam-type femoroacetabular impingement (FAI) in sheep is established. To tap the full potential of this ovine model, one should be able to perform a femoral osteochondroplasty safely. This study was based on previous cadaver experiments on the blood supply to the ovine femoral head and on the biomechanical strength of the proximal femur following offset creation. We hypothesized that offset creation in this ovine FAI model does not lead to (1) avascular necrosis (AVN) of the ovine femoral head or (2) iatrogenic femoral neck fractures and (3) can be performed effectively. DESIGN: In this experimental, controlled, prospective study nine sheep underwent unilateral FAI induction through an intertrochanteric, varus osteotomy. Seventy days following FAI induction, femoral osteochondroplasty was performed. Sheep were sacrificed after another 140 days. Radiographs, computed tomography (CT) scans and MRI were acquired. Histologic samples were stained with hematoxylin-eosin. (1) The multimodal Association Research Circulation Osseous (ARCO) classification was used for assessment of AVN. (2) Femoral neck fractures were assessed with the multimodal imaging approach. (3) Pre- and postoperative (=after sacrifice) alpha angles and femoral neck diameters were compared. RESULTS: (1) No signs for AVN according to the ARCO classification or (2) for femoral neck fractures were detected. (3) Mean alpha angles and femoral neck diameters decreased significantly (p < 0.001) superiorly by at least 30° respectively 4 mm after the offset creation. CONCLUSIONS: Femoral osteochondroplasty can be performed effectively and without the risk of AVN or femoral neck fractures in this ovine FAI model.

Humanization of the mouse mammary gland.

Although mouse models have provided invaluable information on the mechanisms of mammary gland development, anatomical and developmental differences between human and mice limit full understanding of this fundamental process. Humanization of the mouse mammary gland by injecting immortalized human breast stromal cells into the cleared murine mammary fat pad enables the growth and development of human mammary epithelial cells or tissue. This facilitates the characterization of human mammary gland development or tumorigenesis by utilizing the mouse mammary fat pad. Here we describe the process of isolating human mammary stromal and epithelial cells as well as their introduction into the mammary fat pads of immunocompromised mice.

Managing stress through prevention.

This article presents a practical approach to stress management in the clinical laboratory setting. While advocating a proactive approach to stress management, the underlying principle of this paper is that several well-documented human resource techniques should be more widely interpreted and implemented to serve as stress management techniques. Major sources of stress in the clinical laboratory setting are identified, and specific strategies to address these sources are discussed.