In utero placental biometry and histological placental examination in systemic lupus erythematosus and subsequent pregnancy following a stillbirth

H. Kither (1), A.E.P. Heazell (1,2), G. Batra (2), C. Tower (1,2), I. Crocker (1)

(1) University of Manchester, (2) Central Manchester Foundation Trust, United Kingdom

1) Background: Pregnancies affected by Systemic Lupus Erythematosus (SLE) or stillbirth have smaller placental size at delivery and increased prevalence of histologically abnormal features. We examined in-utero placental size and histology at delivery, including complement deposition in women with either: (i) SLE, (ii) prior stillbirth or (iii) uncomplicated pregnancies.

2) Methods: Women with singleton pregnancies with SLE (SP, n=51), prior stillbirth (PL, n=29) and healthy women (NP, n=44) were recruited. In-utero placental dimensions were measured using 2D ultrasound at 17 and 22 (+/- 2) weeks’ gestation and placentas collected at delivery (SP=13, PL=19, NP=9) for histopathological examination. Placentas from stillbirths were obtained from the Department of Histopathology, Royal Manchester Children’s Hospital. Four distinct histopathological groups, were identified: no histological abnormality (NSB, n=25), excess perivillous fibrin deposition (PF, n=16), villitis of unknown aetiology (VUE, n=16) and maternal vascular malperfusion (MVM, n=31). Placental samples were immunostained for anti-complement factor 4d (C4d) or anti-complement factor 3a receptor (C3aR). The area of positive staining was calculated by image analysis software.

3) Results: Second trimester in-utero placental widths were smallest in SP and largest in NP (p<0.05); this was reflected in a trend towards lower placental weight at delivery in SP. Some complement deposition differed from stillbirth to livebirth placentas. Overall, levels of C3aR were highest in livebirth placentas compared to stillbirths (p <0.001), with greatest deposition in MVM and NP, and lowest in SP. C4d deposition was highest in VUE and MVM placentas compared to NSB (p<0.01); there was no difference in C4d deposition between livebirth and stillbirth.

4) Conclusions: Complement deposition varied according to the underlying pathology of stillbirth, offering a potential pathological mechanism and therapeutic target for high risk women.

Ethics statement: Ethics approval wasn’t required and subject safety is protected via anonymization.

International Stillbirth Alliance, Annual Conference on Perinatal Mortality and Bereavement Care, Madrid, Spain. October 5-6th, 2019.

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