The increased use of ultrasound has made it possible for the vast majority of parents to find out in advance whether there’s more than one baby on the way. This wasn’t the case a decade or two ago, when it wasn’t unusual for as many as 40 percent of multiple pregnancies to be undiagnosed prior to labor and delivery.
Even if you haven’t had an ultrasound, certain red flags may alert you and your caregiver to the possibility that you may be carrying twins. These are the warning signals:
■ Fraternal twins tend to run in your family.
■ You have been taking fertility drugs.
■ You experienced excessive nausea and vomiting during the first trimester.
■ Your uterus is growing more quickly or is larger than what would be expected at a particular point in your pregnancy.
■ You notice more fetal movement in this pregnancy than in previous pregnancies (assuming, of course, that this is your second or subsequent pregnancy).
■ More than one fetal heartbeat is heard.
If your caregiver suspects that you may be carrying multiples, he will likely send you for an ultrasound. Early ultrasound can detect more than 95 percent of multiple pregnancies.
Source : The Unofficial Guide to Having a Baby. Second Edition . Ann Douglas and John R. Sussman, M.D. 2004