I agree, this is a strange question to be asking in this day and age. All you have to do is google "exercise during pregnancy" and you'll get thousands of credible websites explaining how good exercise is for you during pregnancy. It just goes to show you that you must take everything with a grain of salt when it comes to advice from other people. Most of the time they don't know what they're talking about. You should not be doing strenuous exercise and make sure your heartrate does not get too high, but a 20 minute walk is the minimum amount of exercise you should be getting. Doesn't your doctor speak to you about this? I have lost 10lbs since I got pregnant and my doctor keeps advising me that regardless of weight loss I should NOT stop exercising although it's been hard to go on my daily walk lately due to snow and ice.
i walk my boy to school then the dog round the park twice a day, it takes about an hour, and is just over a mile.
Dottymouse, I recommend that you buy a pedometer. They're inexpensive and you simply carry it with you in your purse or hook it to your waistband and it counts the steps you take and the distance you have walked while carrying it. I carry mine all day long and aim to walk 10,000 steps which for me is about 4.5miles. I'm suggesting this because from what you've written you may be surprised to find out that you've walked more than what you mentioned. Even at a leisurely pace I walk a mile within 20minutes, you'd have to be walking at a snails pace to walk a mile in an hour. It's worth finding out, I think you're underestimating how far you've walked.