As in most Buddhist countries, foreign women travelling in Myanmar are rarely hassled on the road as they might be in India, Malaysia or Indonesia. However, there have been a few reports of sexual harassment.
Few Myanmar women would consider travelling without at least one female companion, so women travelling alone may be regarded as slightly peculiar by the locals. Lone women being seen off on boats and trains by local friends may find the latter trying to find a suitably responsible older woman to keep them company on the trip.
If you didn't bring tampons, one good place to find them is Yangon's City Mart Supermarket.
'Ladies' (per the posted signs in certain areas) cannot go up to some altars or onto decks around stupas, including the one affording a close-up look at the famous Golden Rock at Kyaiktiyo, or apply gold leaf on the Buddha image at Mandalay's Mahamuni Paya. Also, women should never touch a monk; if you're handing something to a monk, place the object within reach of him, not directly into his hands.
Most locals tend to visit teahouses, restaurants or shops with members of the same sex. Asian women, even from other countries, travelling with a Western man may encounter rude comments.