Severity of HDFN according to the time of antibody detection
Figure 2B and C illustrate severity of HDFN in subsequent pregnancies in
relation to the severity in the first immunized pregnancy for the
subgroups with RhD antibodies detected after giving birth to a
RhD-positive child (A), or during the first pregnancy at risk for
immunization (B). The median HDFN severity was mild in the first
immunized pregnancy in both subgroups and did not differ significantly
between group A and B (P =.794). In both subgroups, disease
severity increased significantly in the subsequent pregnancy as compared
to the first pregnancy (more severe in 14/27 (52%) women in group A,
equal in 10 (37%) equal and less severe in 3 (11%), P =.007, and
18/25 (72%) more severe, 4 (16%) equal and 3 (12%) less severe in
group B, P =.001). The change in HDFN severity in subsequent
pregnancies did not differ between these subgroups (both median +1 HDFN
categories change, range -1 to +3), P =.053).
In group A, 6/27 (22%) of women experienced severe HDFN in the second
pregnancy, as opposed to 12/25 (48%) of women that developed antibodies
in the first pregnancy at risk (group B, OR 3.22, 95% CI 1.0-10.8,P =.051).