Pertussis Infections among Pregnant Women in the United States, 2012-2017.

BACKGROUND Little is known about pertussis among pregnant women, a population at increased risk for severe morbidity from respiratory infections such as influenza. We used CDC's Enhanced Pertussis Surveillance (EPS) system to describe pertussis epidemiology among pregnant and non-pregnant women of childbearing age. METHODS Pertussis cases in women aged 18-44 years with cough onset between 1/1/2012-12/31/2017 were identified in 7 EPS states. Surveillance data were collected through patient and provider interview and immunization registries. Bridged-race, intercensal population data and live birth estimates were used as denominators. RESULTS 1,582 pertussis cases were identified among women aged 18-44 years; 5.1% (76/1499) of patients with known pregnancy status were pregnant at cough onset. Of pregnant patients with complete information, 81.7% (49/60) reported onset during the second or third trimester. The median age of pregnant and non-pregnant patients was 29.0 and 33.0 years, respectively. Most pregnant and non-pregnant patients were white (78.3% vs. 86.4%, p=0.09) and non-Hispanic (72.6% vs. 77.3%, p=0.35). Average annual pertussis incidence was 5.7/100,000 among pregnant and 7.3/100,000 among non-pregnant women. Compared to non-pregnant patients, more pregnant patients reported whoop (41.9% vs. 31.3%), post-tussive vomiting (58.1% vs. 47.9%) and apnea (37.3% vs. 29.0%); however, differences were not statistically significant (p>0.05 for all). A similar proportion of pregnant and non-pregnant patients reported ever having received Tdap (31.6% vs. 32.7%, p=0.84). CONCLUSIONS Our analysis suggests that pertussis incidence and clinical characteristics of disease are similar among pregnant and non-pregnant women. Continued monitoring is important to further define pertussis epidemiology in pregnant women.