Postpartum Ovulation & Period Irregularities: What to Expect

Question
I'm 26 years old and have one son, who turned one in December.  I am still breastfeeding, although we're down to only 3 times a day (no nights).  I had my first period since giving birth on November 25,2005, and it was very normal.  I expected my period at the end of December, but it still hasn't come.  I took a pregnancy test on January 8th (negative).  I'm wondering how common it is to have irregular periods after childbirth.  My periods were very irregular when I was younger, but they became regular over the years (30-35 day cycles). My husband and I want to start trying for another baby this summer.

Thanks for any info. you can provide.

Answer
If you are still nursing, it is possible (and common) to have irregular periods for up to a year after you stop nursing. It may help to purchase an ovulation predictor kit or monitor to help pinpoint the exact day of ovulation each month. If you have a 30-35 day cycle, ovulation usually occurs between cycle day #16-21.