understanding the etiology of premature rupture of membranes amy p. murtha, md vice chair for...
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Understanding the Etiology of Premature Rupture of
MembranesAmy P. Murtha, MD
Vice Chair for Research
Obstetrics and Gynecology
Preterm Birth
Preterm birth defined as delivery prior to 37 weeks gestation
11.9% of all deliveries in the US 500,000 pregnancies in the US per year More than newly diagnosed breast cancer cases
Preterm Birth in the US
14
12
10
8
6
4
2
01990 1992 1994 1996 1998 2000 2002 2004 2006 2008
Year
Late preterm (34 - 36 weeks)
Early preterm (< 34 weeks)
Preterm (< 37 weeks)
2011
Preterm Birth in the US Relative to the World – WHO Data*
Country Preterm Birth Rates
Africa 11.9
North America 10.6
Asia 9.1
Central America 9.1
South America 7.9
Australia/New Zealand 6.4
Europe 6.2*Beck et al 2010: http://www.who.int/bulletin/volumes/88/1/08-062554/en
Preterm PROM
Rupture of membranes prior to 37 weeks without labor
2-3% of all pregnancies are result of PPROM
20% of all perinatal deaths
PPROM Management
34-37 weeks Delivery
<34 weeks Admitted for duration of pregnancy
Monitored for evidence of infection or labor
Clinical detection of infection limited
Maternal fever increases risk of neonatal morbidity
Biomarkers of Intrauterine Infection
Prospective cohort studydaily blood samplesmonitored for infectionreceived antibiotics and steroids
Subjects divided into those with and without funisitis (infection in umbilical cord)
PPROM Study
FunisitisN=54
No Funisitis
N=53P value
% Clinical Chorioamnionitis
22/54 (41%) 1/49 (2%) <.0001
GA at delivery (wks) mean (SD)
28.5 (3.2) 31.5 (2.6) <.0001
Birthweight (grams) 1182 (516) 1716 (547) <.0001
PPROM to delivery interval (mean days)
12.7 (10.3) 16.4 (14.7) .11
Median Serum IL-6 (pg/mL)
Time point FunisitisNo
Funisitis P value
24-48 hours 7.5 (1.8–48.5)
2.8 (0.0–9.6)
<.0001
48-72 hours 5.3 (0.1-55.4)
1.5 (0.0-19.9)
<.0001
>72 hours 2.9 (0.1-42.0)
1.8 (0.0-22.4)
.03
24-72 hours 5.3 (0.1-55.4)
1.9 (0.0-19.9)
<.0001
Infection and Inflammation in PregnancyBlood and Tissue Repository
Over 400 subjects enrolled with over 4,000 samples collected
140 complete sets with daily blood samples collected
Detailed delivery samples collected, barcoded and stored
Maternal and cord blood, placenta, fetal membranes, umbilical cord, buccal swab
Understanding the Etiology of PPROM
Mechanisms resulting in membrane thinning (weakening)
Focus on the chorion cell layer
Amnion
Chorion
Decidua
Etiology of PPROM
Poorly understood and difficult to study
Infection and inflammation important in development of PPROM
Fetal Chorion Layer
Accelerated apoptosis in chorion layerPreterm and term in presence of histologic chorioamnionitis1
Thinned or absent chorion among PPROM subjects2
1 Murtha AP et al. Infect Dis Obstet Gynecol 2002;10:93–962 George RB et al. Am J Perinatol 2008;25:29–32
Moving forward…prospective collection
• Fetal membrane chorion thickness atmembrane rupture
distant from rupture
Bacterial presence in fetal membranes membrane rupture
distant from rupture
Primary cell culture and cell line
Methods – Data Collection
46 paired membrane samples collectedRupture site (rupture) or overlying cervix
Distant to rupture site (distant)
IHC Methods – Sample Processing
Chorion and choriodecidual thickness measured using Image J® software
Chorion
Choriodecidua
FISH Methods – Sample Processing
Bacteria identified using fluorescence in situ hybridization (FISH) with Alexa Red probe to 16s rRNA subunit
Custom oligonucleotide sequence 5´-F-ACTGCTGCCTCCCGTAGGAGTTTATTCCTT (Invitrogen®)
PPROM Preterm Labor
Preterm, No Labor
Term Labor
Term, No Labor
0
100
200
300
400
RuptureDistant
Chorion Thickness by Clinical Group
Mea
n T
hick
ness
(µ
m)
*
^
* P = 0.0024 ^ P = 0.0015
Number of Bacteria per Membrane Quadrant by Clinical Group
PPROM Preterm Labor
Preterm, No Labor
Term Labor
Term, No Labor
0
20
40
RuptureDistant
*P < 0.0005 ^P = 0.002
Num
ber
Bac
teria
Per
Qua
dran
t
^
*
PPROM Preterm Term0
10
20
30
40
RuptureDistant
Number Bacteria per Membrane Quadrant Without Chorioamnionitis
Num
ber
Bac
teria
Per
Qua
dran
t *P = 0.03 ^P = 0.006
N = 7 N = 14 N = 16
^
*
What else….
Bacterial DNA sequencing from fetal membranes Ureaplasma parvum as a pathogen in pregnancy Thrombin’s role in fetal membrane integrity Cigarette smoke exposure and effect on membranes and
placenta Progesterone’s role in modulating the inflammatory
response MMP activity and regulation of progesterone Mechanisms of progesterone function through non-
nuclear PR (PGRMC1)
Clinical Research in OB/GYN MFMU Clinical Trials Network (Federal) Antenatal Late Preterm Steroids (ALPS): A
Randomized Placebo-Controlled Trial DMID vaccine trials (Federal) National Children’s study (Federal) Newborn Epigenetic Study (NEST) (Federal) Children’s Environmental Health Initiative (Federal) 17OH PC for Prevention of Recurrent Preterm Birth
(Industry) Labor induction with misoprostil (Industry) Wound Vac in Obesity (Industry) Prenatal diagnosis with Maternal free fetal DNA
(Federal/Industry) The effects of SCDs on fibrinolysis in patients
undergoing Cesarean Delivery (Industry) A Prospective Study of the Hemostatic Differences
between Women with and without Vaginal Bleeding in Pregnancy (Federal)
An Intervention to Maximize Research Sample Collection for Pregnant Subjects at Delivery (Duke)
Comparing Focused Ultrasound and Uterine Artery Embolization for Uterine Fibroids (Federal)
Bridging Interdisciplinary Research Careers in Women’s Health (BIRCWH) K23 (Federal)
Pelvic Floor Clinical Trials Network (Federal) Management of Menorrhagia in Women with Bleeding
Disorders (Federal) Neural Prosthetic Control of Continence and
Micturition (Federal) Effectiveness Of Sacrospinous Ligament Fixation
(SSLF) versus Uterosacral Ligament Suspension (Federal)
Cervical Intraepithelial Neoplasia Cohort Study (Federal)
Ambulatory Treatments for Leakage Associated with Stress (Federal)
Anticholinergic vs. Botox Comparison study: The ABC Trial (Federal)
Outcomes Following Vaginal Prolapse Repair and Mid Urethral Sling (OPUS) Trial (Federal)
Prospective randomized study of sperm production in healthy volunteers receiving pregabalin or placebo. (Federal/Industry)
GIS Health Data in the Blanchard Neighborhood of Haiti: Assessment of Community Needs Guide Community Public Health Practice? (Foundation)
Molecular Markers of Human Sperm Function (Federal)