Almost16 yo daughter only ever had 1 period ,10 mos ago. is tall, thin, athletic. asked my obgyn & didnt seem too concerned. what can be done to help?

Passage of time: The first cycle is often dictated by estrogen effect and not preceded by an egg release. Both events are part of the normal cycling factors. In the first year or so there is often irregularity. A lean body mass of an athlete can also reduce/prevent cycle activity. Your obgyn could certainly put her on hormones for a while and trigger menses, or you could let some time pass & she may start cycling.