The Link Between In Vitro Fertilization (IVF) and Premature Birth

Reduce your risk of preterm birth from IVF

Expectant mother in hospital labour ward
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In vitro fertilization (IVF) and other fertility treatments are a gift to families who want to have a baby but can't conceive. IVF has been used to treat infertility for over 30 years and helps more than 57,000 American families to have a child each year. However, the process is not without its risks. One important risk that you should consider with IVF is the risk of preterm birth. By understanding the increased risk of premature birth and learning how to reduce it, you can make a more informed decision about conceiving through IVF.

The Risk for Preterm Birth After IVF

No matter how you conceive, your chances of having a premature baby vary depending on a number of factors. Where you live, the number of babies you're carrying, your age, your general health (including your weight, alcohol and tobacco use, and diet), and your socioeconomic status can all affect your chances of having a premature baby.

Even after adjusting for other factors that might cause a higher rate of preterm birth, babies conceived through IVF have a higher chance of being born early than babies conceived naturally or through other fertility treatments. Twins conceived after IVF are 23 percent more likely to be born early than twins conceived naturally. IVF singletons are about twice as likely to be premature as singletons conceived naturally.

Why IVF Causes Premature Birth

Doctors don't know exactly why IVF babies are born earlier than other babies.

More research is being done, but so far the studies suggest that a combination of the IVF procedure itself and factors in the mom may cause the increased risk of delivering early. These factors include:

  • Hormonal causes: In an IVF cycle using fresh embryos, you're given a super-dose of hormones to increase the number of eggs you will release. Some scientists believe that these hormones may affect the way the embryo implants in your uterus.
  • Multiple embryos: Twins and other multiples are more likely to be born early than singletons, no matter how they're conceived. Because two or more embryos are often implanted, increased multiple births help to drive up the numbers of IVF babies born early.
  • Increased medical management: IVF pregnancies are carefully monitored by both the parents and the physician. Because these pregnancies are considered so precious, doctors and parents may be more likely to deliver a baby early due to a complication that might not be as concerning in pregnancies that are less carefully monitored.
  • Maternal factors: Factors that cause infertility may play a role in why IVF increases the risk of premature birth. Moms who conceive through IVF also tend to be older and heavier than moms who conceive naturally, which also increases the risk.

Reducing Your Chances of Premature Birth Caused by IVF

Although you can't remove the risk of premature birth caused by IVF, you can reduce it. Here are some ways:

  • Getting healthy can reduce your chances of having your baby prematurely, no matter how your baby is conceived. Eat right, exercise, and don't smoke. By maintaining a healthy weight and a healthy body, you will increase your chances of carrying your baby to term.
  • Weigh the options, including single embryo transfer. IVF is expensive, and implanting two or more embryos may seem to make the most sense. Past studies have shown that the risk for preterm birth jumps significantly when multiple embryos are implanted instead of one; however, one recent two-year study showed that elective single embryo transfer doesn't reduce the risk of premature birth and seems to even increase the risk.
  • Don't be afraid to use frozen embryos. Some studies have shown that frozen embryos have better outcomes than fresh embryos. Frozen embryos are implanted at a more natural time in your cycle, and weaker embryos may not survive freezing.

    Sources:

    Fechner AJ, Brown KR, Onwubalili N, et al. Effect of Single Embryo Transfer on the Risk of Preterm Birth Associated With In Vitro FertilizationJournal of Assisted Reproduction and Genetics. 2015;32(2):221-224. doi:10.1007/s10815-014-0381-2.

    Hayashi M, Nakai A, Satoh S, Matsuda Y. Adverse Obstetric and Perinatal Outcomes of Singleton Pregnancies May Be Related to Maternal Factors Associated With Infertility Rather Than Type of Assisted Reproductive Technology Procedure UsedFertility and Sterility. October 2012;98(4):922-927. doi:10.1016/j.fertnstert.2012.05.049.

    Maheshwari A, Pandey S, Shetty A, Hamilton M, Bhattacharya S. Obstetric and Perinatal Outcomes in Singleton Pregnancies Resulting From the Transfer of Frozen Thawed Versus Fresh Embryos Generated Through In Vitro Fertilization and Treatment: A Systematic Review and Meta-AnalysisFertility and Sterility. August 2012;98(2):368-376. doi:10.1016/j.fertnstert.2012.05.019.

    Sazonova A, Kallen K, Thurin-Kjellberg A, Wennerholm U, Bergh C. Factors Affecting Obstetric Outcome of Singletons Born After IVFHuman Reproduction. July 2011;26:2878-2886. doi:10.1093/humrep/der241.