1 Use moderate intensity, which is sufficient to improve cardiovascular fitness, muscle strenght and flexibility. 2  Perform exercises regularly: cardiovascular exercise: 3 to 5 times per week, strenght training: 2 to 3 times per week.
The pregnancy starts from the first day of her last menstrual period. Normally 2 weeks before ovulation. An ultrasound is the most accurate way to determine pregnancy dates. So yes, she can be 6 weeks and 3 days pregnant even though you only met 5 weeks ago because two of those weeks were before conception.
As the pregnancy progresses, the accuracy of an ultrasound for predicting due dates decreases. Between 18 and 28 weeks of gestation, the margin of error increases to plus or minus two weeks. After 28 weeks, the ultrasound may be off by three weeks or more in predicting a due date. Thus, later in pregnancy, ultrasound measurements are more valuable for evaluating the baby's growth over time (compared with earlier measurements) than they are for predicting a due date.