Are women in Japan pregnant for 10 months?
On the other hand, if you’re counting the more traditional lunar months of exactly 28 days (i.e. 4 weeks), then 40 weeks = 10 months. The Japanese belief that a pregnancy lasts ten months refers back to their original calendar that used these shorter months.
I have a nifty little `pregnancy calendar` on my Ipod which I downloaded for free, called 妊婦カレンダー which counts the days, weeks and months for me. I like the Japanese system, because I now know that every Tuesday, I am one more week along than the previous Tuesday; and every 4 Tuesdays, I can add another month to the pregnancy. So simple!