With more young women reaching their childbearing years after Fontan, researchers are finding that their pregnancies may be complicated due to poor circulation. Researchers at Mayo Clinic reviewed the pregnancies of several women with Fontan anatomy. Our first #ResearchRecap reviews this article in a reader-friendly way.
(2-3 minute read)
The pregnancies of seven women (13 babies total) at Mayo Clinic between 2002 and 2018 were studied, including detailed microscopic tests of the placentas after birth. All of the women were still alive when the paper was written. Two women developed preeclampsia (high blood pressure during pregnancy), and the membranes ruptured early (waters broke) in two other women. All 13 babies were born alive, but the average time of delivery was 35.4 weeks gestation – short of the >37 week time that is considered full-term. The average birth weight was 4.8 lbs. When reviewing the placentas, they were found to be thin, underdeveloped, poorly connected to the uterine wall, and less able to circulate blood compared to normal placentas.
Because the Fontan operation already results in increased pressure in the veins, particularly in the abdomen, the researchers note that “the rigors of pregnancy may prove difficult for women with Fontan physiology.” Additionally, the chronically poor blood circulation and lower oxygen saturation levels experienced by many of these women may affect the development of the placenta and lead to preeclampsia and poor blood flow to the baby.
The researchers note that some women after Fontan may be able to have successful pregnancies. However, because pre-term deliveries and lower birth-weights should be expected, “Pre-conception counseling, cardiology and obstetrical evaluation, peri-partum care and follow-up need to be meticulous.” Finally, they note two important questions for women considering pregnancy after Fontan: 1) Whether the increased stress on blood flow to organs and tissues will compromise her own quality of life and/or longevity, and 2) What is the probability of a favorable outcome for the baby?
More research in this important area will be needed in the coming years as more women with Fontan physiology enter their reproductive years.
Phillips AL, Cetta F, Kerr SE, Cheek EH, Rose CH, Bonnichsen CR, Phillips SD. The placenta: A site of end-organ damage after Fontan operation. A case series. Int J Cardiol. 2019 Aug 15; 289:52-55 Epub 2019 Feb 05
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