Environmental exposures and fecundability: The Norwegian Mother, Father, and Child Cohort study.

Previous studies have linked certain environmental exposures to reduced fecundability, influencing exposure recommendations. We continue to encounter numerous environmental exposures in our everyday lives, and further evidence is needed regarding their effects on fecundability. We evaluated associations between various self-reported environmental exposures and fecundability, measured as time to pregnancy, in 64,942 women and 53,219 men participating in the Norwegian Mother, Father, and Child Cohort study (MoBa).

Type of infertility and prevalence of congenital malformations.

Background: Children conceived with assisted reproductive technologies (ART) or after a long waiting time have a higher prevalence of congenital malformations, but few studies have examined the contribution of type of infertility.

Objectives: To quantify the association between causes of infertility and prevalence of malformations.

Methods: We compared the prevalence at birth of all and severe malformations diagnosed up to age 2 between 6656 children born in 1996-2017 to parents who had previously been assessed for infertility a an academic fertility clinic ("exposed") and 10,382 children born in the same period to parents with no recent medical history of infertility ("reference").

Inferring fetal growth restriction as rare, severe, and stable over time.

Reduced birthweight is a marker of pathologies that impair growth and also decrease survival. However, "fetal growth restriction" remains poorly defined. Assuming that birthweight itself has no causal effect on neonatal mortality, we can estimate the features of pathological fetal growth that would be required to produce the observed pattern of weight-specific mortality.