Talk to Gynecologist on Irregular Periods Or Bleeding?

my wife and I have been married for 6 months, she gets her period around every 4th of each month, last month she got her periods 10 days late because we feared she might be pregnant but she got her periods but very late, this month she got periods today: 23days late, is this normal? we haven't taken a pregnancy test? or this a serious situation?