Volume 28, Number 9—September 2022
CME ACTIVITY - Synopsis
Fetal Loss and Preterm Birth Caused by Intraamniotic Haemophilus influenzae Infection, New Zealand
, Caitlin Sharpe, Thomas Wong, Tim Cutfield, Arier Lee, Stephen McBride, Matthew Rogers, May Ching Soh, Amanda Taylor, Susan Taylor, and Mark Thomas
Table 1
Pregnancy-associated invasive Haemophilus influenzae case demographic and clinical data, New Zealand*
| Variable | Maternal cases | Neonatal cases | Total pregnancies |
|---|---|---|---|
| Total |
38 |
16 |
52† |
| Maternal ethnicity | |||
| European | 4 (10.5) | 5 (31.3) | 8 (15.4) |
| Māori | 17 (44.7) | 4 (25) | 20 (38.5) |
| Pacific | 14 (36.8) | 6 (37.5) | 20 (38.5) |
| Other |
3 (7.9) |
1 (6.3) |
4 (7.7) |
| Median maternal age, y (range)‡ |
25 (15–44) |
29.5 (18–43) |
25 (15–44) |
| Socioeconomic deprivation‡ | |||
| Quintile 5 | 22 (59.5) | 6 (46.1) | 26 (54.2) |
| Quintile 4 | 10 (27.0) | 2 (15.4) | 12 (25.0) |
| Quintile <3 |
5 (13.5) |
5 (38.5) |
10 (20.8) |
| Median gestation,‡ wk (range) |
32 (8–40) |
34 (26–41) |
32 (8–41) |
| Pregnancy outcomes | |||
| Intrauterine death <24 weeks’ gestation | 13 (34.2) | 0 | 13 (25.0) |
| Intrauterine death >24 weeks’ gestation | 3 (7.9) | 1 (6.3) | 4 (7.7) |
| Live preterm birth | 13 (34.2) | 10 (62.5) | 21 (40.4) |
| Live birth at term | 6 (15.8) | 4 (25) | 10 (19.2) |
| Pregnancy outcome unclear |
3 (7.9) |
1 (6.3) |
4 (7.7) |
| Clinical diagnosis | |||
| Intraamniotic infection§ | 34 (89.5) | 2 (12.5) | 36 (69.2) |
| Primary bacteremia | 4 (10.5) | 12 (75.0) | 14 (26.9) |
| Pneumonia | 0 | 1 (6.3) | 1 (1.9) |
| Meningitis | 0 | 1 (6.3) | 1 (1.9) |
| Other |
0 |
0 |
0 |
| Specimens culturing H. influenzae¶ | |||
| Maternal blood culture | 13 | 1 | 14 |
| Neonatal blood culture | 2 | 15 | 17 |
| Placental tissue or products of conception | 30 | 3 | 33 |
| High vaginal swab specimens§ | 17 | 0 | 17 |
| Cerebrospinal fluid | 0 | 1 | 1 |
*Values are no. (%) unless otherwise indicated. †In 2 pregnancies, invasive H. influenzae infection occurred in the mother and the neonate. Thus, the 38 maternal cases and 16 neonatal cases occurred in 52 unique pregnancies. ‡Data for gestational duration were unavailable for 2 neonatal cases and 1 maternal case; maternal age data were unavailable for 2 cases; 2013 area-level New Zealand deprivation index (NZDep2013) data were unavailable for 2 cases. NZDep2013 quintile 5 is the most deprived socioeconomic area, and quintile 1 is the least deprived socioeconomic area. §Intraamniotic infection was defined as H. influenzae isolated from placental samples or products of conception (with or without maternal/neonatal H. influenzae bacteremia) or maternal H. influenzae bacteremia with H. influenzae concurrently isolated from high vaginal swab specimens. Isolation of H. influenzae from a high vaginal swab specimen alone, without isolation from another site, was insufficient to meet the case definition for invasive H. influenzae disease. Invasive disease was diagnosed in 9 cases with associated maternal bacteremia, 1 case with associated neonatal bacteremia, and 7 cases with documented infection of placental tissue. ¶The total number of positive culture results exceeds the number of cases because in some cases H. influenzae was isolated from >1 site.