Most moms carrying twins go into labor at 36 to 37 weeks, as opposed to 40 in a single pregnancy, Al-Khan says, and some may go even earlier. Generally, if the twins are born after 34 weeks, there should not be a major concern, but a premature baby is still a premature baby, he says.
False pregnancy in humans is less common, and may sometimes be purely psychological. It is generally believed that false pregnancy is caused by changes in the endocrine system of the body, leading to the secretion of hormones that cause physical changes similar to those during pregnancy.
Defective pregnancy tests. Expired tests or faulty home pregnancy tests can also lead to false positive results. Always check the expiration date before testing to assure accurate results. Keep in mind, even with the highest quality control, an occasional defective test may occur.