Send to

Choose Destination
Vaccine. 2012 Jun 22;30(30):4445-52. doi: 10.1016/j.vaccine.2012.04.081. Epub 2012 May 5.

A(H1N1)v2009: a controlled observational prospective cohort study on vaccine safety in pregnancy.

Author information

Institute for Clinical Teratology and Drug Risk Assessment in Pregnancy, Charité - Universitätsmedizin Berlin, Germany.



A(H1N1)v2009 influenza vaccination of pregnant women was a challenge for health care providers, as little safety data were available.


We prospectively followed the pregnancies of women who were vaccinated at any time during pregnancy or ≤ 4 weeks prior to conception and compared these outcomes to a control cohort matched by the estimated date of birth. Primary endpoints: rate of spontaneous abortion and major malformations. Secondary endpoints: preeclampsia, gestational age at birth, and birth weight.


Pregnancy outcome of 323 women immunized with adjuvanted or non-adjuvanted A(H1N1)v2009 influenza vaccines from 2009-09-28 to 2010-03-31 were compared to 1329 control subjects. The risk for spontaneous abortions (HR 0.89; 95% CI 0.36-2.19) and the rate of major malformations (all trimesters: OR 0.87; 95% CI 0.38-1.77; preconception and first trimester exposure: OR 0.79; 95% CI 0.13-2.64) did not vary between the two cohorts. Furthermore, there was no increase in preeclampsia, prematurity, and intrauterine growth retardation in the vaccinated cohort.


The results of our study do not indicate a risk for the pregnant woman and the developing embryo/fetus after H1N1 vaccination. We provide and apply methods novel in observational studies on pregnancy outcome, especially if a single dose exposure is investigated.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center