The first 11 weeks pregnant with twins or multiples

Congratulations, it’s twins or multiples!

The fact that there’s not one baby but two or more often isn’t visible in an ultrasound until sometime between weeks 8 and 10 of gestation. This means that by the time you find out you’ve got double (or triple, or quadruple) the trouble, toes, and tiny socks coming your way, you’ve been preparing for and learning about the possibility of just one baby for a while already.

How do twins and other multiples happen?

There are a few different ways you might have ended up pregnant with multiples. The only way to tell which it was is to find out whether you’re carrying identical or fraternal multiples, which often isn’t clear until near the end of the first trimester.

Identical twins and multiples happen when a single fertilized egg divides into two (or even three, or four!) identical eggs. If you’re pregnant with identical twins or other multiples, it means that they have the same genetic material, the same physical sex characteristics, and will look the same (or very similar). They commonly share a placenta, but if the fertilized egg splits at the right time, they may have separate placentas. Each baby usually has a separate amniotic sac, but not always. Identical twins, triplets, or other multiples happen by chance, so they don’t run in families. They’re also the less common type of multiples.

More commonly, twins and other multiples are fraternal. This means that they come from different, distinct fertilized eggs, and are no more similar genetically than any other set of siblings. Fraternal multiples occur when more than one egg is released and fertilized during ovulation. Fraternal twins each have their own placentas and amniotic sacs.

Multiples of more than two can be, and often are, a mixture of identical and fraternal. For example, in a set of fraternal twins, one of the two eggs may split to create two identical twins, which leaves triplets: two of whom are identical and one of whom is fraternal.

What can I expect from a twin or multiple pregnancy?

If you’ve been pregnant before, you may notice some differences between your twin or multiple pregnancy and a singleton pregnancy. The American College of Obstetricians and Gynecologists reports that women carrying multiples pregnancies often experience more intense symptoms than they might during a singleton pregnancy, especially an increase in nausea, morning sickness, and breast tenderness.

Since twin and multiple pregnancies carry increased risks of certain complications, there’s a good chance your healthcare provider will recommend more frequent checkups. They’ll probably also suggest more frequent ultrasounds, so that they’ll be able to more accurately keep an eye on your babies’ growth.

Sources

• American College of Obstetricians and Gynecologists. “Multifetal gestation: Twin, triplet, and higher order multifetal pregnancies.” National Guideline Clearinghouse. U.S. Department of Health and Human Services, May 2014. Retrieved January 25 2018. https://www.guideline.gov/summaries/summary/48025/multifetal-gestations-twin-triplet-and-higherorder-multifetal-pregnancies.
• Stephen T. Chasen, Frank A. Chervenak. “Twin pregnancy: Labor and delivery.” UpToDate. Wolters Kluwer, December 2017. Retrieved January 25 2018. https://www.uptodate.com/contents/twin-pregnancy-labor-and-delivery.
• Richard A. Ehrankranz, Mark A. Mercurio. “Periviable birth.” UpToDate. Wolters Kluwer, December 2017. Retrieved January 25 2018. https://www.uptodate.com/contents/periviable-birth-limit-of-viability?search=viability%20milestones&source=search_result&selectedTitle=2~150&usage_type=default&display_rank=2.
• William Goodnight, Roger Newman. “Optimal nutrition for improved twin pregnancy outcome.” Obstetricians & Gynecologists. 114(5): 1121-1134.
• Atsushi Kuno, Masashi Akiyama, Toshihiro Yanagihara, Toshiyuki Hata. “Comparisons of fetal growth in singleton, twin, and triplet pregnancies.” Human Reproduction. 14(5): 1352-1360. https://academic.oup.com/humrep/article/14/5/1352/766210.
• http://www.mfmsm.com/media_pages/MFM-Optimal-nutrition-for-improved-twin-pregnancy.pdf.
• Kenneth J. Leveno, J. Gerald Quirk, Peggy J. Whalley, Robert Trubery. “Fetal lung maturation in twin gestation.” American Journal of Obstetrics and Gynecologists. 148(4): 405-11. March 1984. Retrieved January 25 2018.
• Mayo Clinic Staff. “Twin pregnancy: What multiples mean for mom.” Mayo Clinic. Mayo Clinic, December 13 2014. Retrieved January 25 2018. https://www.mayoclinic.org/healthy-lifestyle/pregnancy-week-by-week/in-depth/twin-pregnancy/art-20048161.
• “FAQ: Multiple pregnancy.” American College of Obstetricians and Gynecologists. American College of Obstetricians and Gynecologists, July 2015. Retrieved January 25 2018. https://www.acog.org/Patients/FAQs/Multiple-Pregnancy.
• “Tracking your weight, for women who begin a twin pregnancy at a normal weight.” Centers for Disease Control and Prevention. Centers for Disease Control and Prevention. Retrieved January 25 2018. https://www.cdc.gov/reproductivehealth/pdfs/maternal-infant-health/pregnancy-weight-gain/tracker/twins/normal_twin_weight_tracker__508tagged.pdf.
• “Twin pregnancy obstetric care guidelines.” Brigham and Women’s Hospital. Brigham and Women’s Hospital, June 28 2016. Retrieved January 25 2018. http://www.brighamandwomens.org/Departments_and_Services/obgyn/Services/twin-pregnancy/twin-pregnancy-obstetric-care-guidelines.aspx?sub=6.