For how we live.
In a study of 543,167 cycles, calendar-based apps misclassified a fertile day as safe in two-thirds of cycles. Apps that track a real biological signal do better, but plain calendar apps remain the most common kind.
Whole-genome sequencing of 78 families put the figure at two mutations per year of paternal age. A cohort of 40 million US births found small increases in preterm birth and gestational diabetes.
The 2023 global guideline puts lifestyle first for everyone, letrozole first for fertility, and the pill for cycles and excess hair — while rating much of its own evidence low to moderate quality.
In two large clinics, the live birth rate per woman who returned to use her eggs was around 39-50% under 35 or 38, but far lower for older women — and most women who froze never came back to use them.
In modern couples timing intercourse, an estimated 18% of women aged 35-39 failed to conceive within a year — not one in three. The most alarming figures come from models, not from watching real couples try.
An 876-participant double-blind trial across 24 Chinese fertility centres nearly doubled serum 25-OHD in women with PCOS. Live births were 52.0% against 50.2% on placebo.