My daughter just turned 17 and she has irregular periods - some are 4 months apart - she had one in june and july - but none since then. Should I be alarmed? And what should I do? She is not sexually active.

Consult an OB/Gyn. Although this is not the expected pattern for a woman's menstrual pattern it dose happen with some frequency. The ob/gyn can often give you some answers about how ocp's can create predictable cycles & the impact of this pattern on your daughters fertility later on. Sometimes they can obtain needed data from an abdominal ultrasound & avoid the discomfort of a pelvic exam . Good luck.
See below. I would not be alarmed. However, she should see a gynecologist. She may benefit from ocps.

Related Questions

My daughter has irregular periods, shes 16 not sexually active and is matured since she was 12. Her periods come after every 4-6 months for 7=10 days.

Irregular periods. Having irregular periods may not be such a bad idea despite the inconvenience of 7-10 days every 6 months. Obviously, it seems like you and your daughter have a concern. My best advice is to consult a gynecologist who may prescribe hormones taken every day to regulate her periods. Read more...