1. 9th IAS CONFERENCE ON HIV SCIENCE PARIS, FRANCE 23-26 JULY
Stillbirth in HIV-infected women delivering in UK/Ireland between 2007 and 2015
G. Favarato, R.Sconza, H. Peters, A. Horn, K.Francis, H. Bailey,
P. Tookey, C. Thorne
UCL Great Ormond Street Institute of Child Health, London, UK
9th IAS CONFERENCE ON HIV SCIENCE PARIS, FRANCE JULY

2. Background Aim Study design:
Causes of stillbirth (SB) are multifactorial and incompletely understood
In UK/Ireland previously reported higher SB rate in HIV+ women
Aim
To explore current SB rate and associated risk factors in HIV+ women delivering in UK/Ireland using data from a national surveillance study
Study design:
Pregnancies in HIV+ women reported to the National Study on HIV in Pregnancy and Childhood (NSHPC) in
Inclusion: singleton delivered at ≥ 24 gestational weeks (GW)
Definition of SB: an infant delivered at ≥24 (GW) showing no signs of life
Statistical analysis: multivariable Poisson regression

3. Characteristics: pregnancies
SB/TOTAL
% SB
89/10405
0.9
Delivery year
41/3884
1.1
30/3621
0.8
18/2900
0.6
Region of origin
Europe/WEWC
8/2004
0.4
SSA
71/7752
Other
7/528
1.3
Maternal age
<28 years
12/2249
0.5
28-32 years
23 /2494
33-36 years
28 /2848
1.0
>36 years
26 /2814
SB/TOTAL
% SB
Parity
Primiparous
30/2698
1.1
Multiparous
50/7197
0.7
CD4 count
cells/mm3
>350
38/6407
0.6
≤350
41/3360
1.2
Antenatal ART based regimen
PI/r-
48/5454
0.9
NNRTI-
21/2427
INSTI-
2/120
1.7
Other
0/335
0.0
Switched
11/1615
SB=stillbirth; WEWC= westernised countries; SSA= sub-Saharan countries; PI/r= ritonavir boosted protease inhibitors; NNRTI=non-nucleoside reverse transcriptase inhibitors; INSTI=integrase inhibitors

4. Characteristics: Stillbirth (SB) infants
Compared to live-born infants, SB more likely:
Born pre-term:
Median gestation weeks: 33 (IQR 27-37) vs 39 (38-40)
Very preterm (<34 GW): 46/89 (52%) vs 409/10302 (4%)
Small for gestational age1 (SGA): 28/62 (55%) vs. 2208/7774 (21%
To be of male gender:
39/67 (58%) vs. 5164/10290 (50%)
Have congenital abnormalities:
9/61 (15%) vs. 285/10000 (3%)
1 Based on sex-specific US standard

5. Conclusions Risk factors for SB
Significant risk factors for SB from multivariable analysis:
antenatal CD4 count ≤350cells/µL IRR 1.73 [95% CI 1.05, 2.86]
primiparity IRR 1.85 [1.10, 3.12]
older age in women >36yr vs women <28 years, IRR 4.12 [1.49, 11.35]
SSA origin IRR 3.26 [1.07, 9.95] or other world region IRR 5.59 [1.46, 21.48] vs Europe/WEWC.
Conclusions
SB rate (0.9%) higher than that in UK general population (~0.4%)
Study limitations:
no routine data collection for some risk factors for SB (e.g. SES, smoking, BMI)
unable to classify SB as antepartum vs intrapartum
Future work
enhanced data collection within an embedded audit of pregnancies ending in SB
to standardise SB rate by maternal origin