Dissertations & Theses (Open Access)

Maternal Use Of Hot Tub/Jacuzzi Or Sauna And Structural Birth Defects

Date of Award

Fall 12-2018

Degree Name

Master of Public Health (MPH)


James E. Hixson, Phd

Second Advisor

Kim Waller, Phd


Background: A previous analysis of the National Birth Defects Prevention Study (NBDPS) examined the association between maternal exposure to a hot tub or sauna during early pregnancy and 17 non-cardiac structural birth defects and found an increased risk for anencephaly and gastroschisis. Our aim was to conduct an updated analysis using data from the final version of the NBDPS, assessing associations between maternal use of a hot tub (or sauna) and a total of 38 anomalies including 15 cardiac and 6 non-cardiac birth defects that were not assessed in the previous NBDPS analysis. Methods: We used interview data from 32,200 case mothers and 11,829 control mothers who participated in the NBDPS from 1997-2011. We calculated adjusted odds ratios (aORs) assessing the association between maternal exposure to a hot tub/jacuzzi or sauna during early pregnancy and offspring with 38 birth defects, stratified by the duration and frequency of the exposures. Findings: Mothers of infants with anencephaly and gastroschisis were significantly more likely to report any hot tub (or sauna) use during the first two months of pregnancy; aORs of 1.47 (95% Cl 1.00 to 2.17) and 1.52 (95% Cl 1.13 to 2.05), respectively. Significant protective aORs for any use of hot tub (or sauna) were observed for three birth defects. When results were restricted to those who used a hot tub (or sauna) for more than 1 day during early pregnancy, we found significantly elevated aORs for anencephaly, spina bifida, gastroschisis, and anomalous pulmonary venous return with two protective odds ratios. Conclusion: Among women who reported using a hot tub/jacuzzi, or sauna for longer periods of time and more frequently, more birth defects had elevated aORs and the odds ratios were higher. These results suggest that mothers who use hot tub/jacuzzi, or sauna during early pregnancy may have an increased risk of specific types of birth defects, especially if they use a hot tub/jacuzzi, or sauna frequently and for longer periods of time. We have both elevated and protective ORs. These results should be interpreted cautiously as some of the associations observed between maternal use of hot tub/jacuzzi, or sauna and specific birth defects, may be due to chance.

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