Table 5.

Frequency of Major Birth Defects and Adjusted Relative Risks for Receipt of Quadrivalent Human Papillomavirus Vaccine During the Periconceptional Period, During Pregnancy, or Both Exposure Periods Compared With Receipt of the Quadrivalent Human Papillomavirus Vaccine During the Comparison Period, Vaccine Safety Datalink, 2007–2013

Quadrivalent HPV Vaccine	No. of Live Births	Major Birth Defects	Adjusted Prevalence Ratio* (95% CI)	Adjusted Prevalence Difference/10,000 Live Births (95% CI)
During periconceptional period	601†	11 (1.8)	1.04 (0.75–1.5)	0.3 (−1.7 to 2.4)
During pregnancy	542	11 (2.0)	1.0 (0.52–1.9)	0.1 (−1.2 to 1.4)
During periconceptional period or during pregnancy	1,143	22 (1.9)	1.04 (0.66–1.7)	0.2 (−0.7 to 1.1)
During comparison period	6,843†	120 (1.8)	Referent	Referent

HPV, human papillomavirus.

Data are n (%) unless otherwise specified.

^*Propensity-adjusted, quintiles of propensity score included in the model parameterized as a five-category variable. Variables included in the model were site, year of delivery, maternal age, prenatal care index, poverty, pre-existing maternal conditions.

^†For major birth defects analyses, we excluded infants with less than 4 months’ insurance enrollment, no outpatient visits at a Vaccine Safety Datalink site, maternal use of teratogenic medication during pregnancy or within 6 months of last menstrual period, maternal congenital infections (toxoplasmosis, syphilis, varicella, rubella, and cytomegalovirus), pre-existing maternal diabetes.