When Can I Learn the Sex of My Baby (and Do Ultrasounds Ever Lie)?

By Beth M. Iovinelli, RN, BSN, IBCLC

Q: When can I find out the sex of my baby? Do the ultrasound technicians ever make mistakes?

A: Ultrasounds are used to help screen for abnormalities or deformities during pregnancy. While checking on the well-being of your baby, the ultrasound technician may also be able to determine the gender of your baby as early as week 16 or week 17 of pregnancy (however, between weeks 18 and 26 is best). If you're looking forward to this ultrasound as a chance to find out the sex of your child, be prepared; babies do not always cooperate. Many times babies aren't in the optimal position for visualizing the genitals.
Generally during one of these prenatal appointments and ultrasound checkups, your technician will be measuring the head, femur, abdomen, and amount of amniotic fluid as you're hoping to get a glimpse of your baby's gender. These are his or her priorities, and having an ultrasound simply for determining the sex of the baby is not recommended. In fact the ACOG (American College of Obstetricians and Gynecologists) has recommended not offering ultrasounds exclusively for determining the sex of a child. Long-term studies on high exposure to ultrasound are not known, and it is best to be prudent and keep your exposure to the minimum.
Although the quality and accuracy of gender detection during ultrasound is improving, amniocentesis or chorionic villus samplings are more accurate. Your technician will do his/her best to determine gender, if your baby cooperates. However, mistakes can and do happen (so, you can't ask your technician to repaint the nursery!).
To know or not to know … that is the question. This is a choice that you will have to make with your partner. But keep in mind that knowing ahead of time will not make your delivery any less exciting or your baby any less precious.

Beth M. Iovinelli, RN, BSN, IBCLC

Beth M. Iovinelli, RN, BSN, IBCLC, has worked as a maternal child health nurse in both labor and delivery and post partum since 1994. She has written for various newsletters and websites, taught thousands of parents, and trained nurses, doctors, and nutritionists. In 2004, she contributed to the Don't Panic Pregnancy book (Lyons Press) written by Emmy Award-winning producer Judy Morris. Iovinelli works as a maternal child health educator and lactation consultant at Norwalk Hospital in Norwalk, Connecticut, and is currently being featured in the Newborn Channel's latest breastfeeding program, Breast is Best, which is broadcast in more than 1,000 hospitals nationwide.

All articles by Beth M. Iovinelli, RN, BSN, IBCLC