Prematurity Module
AnS 536
April 22, 2016
Overview
Prematurity
 Preterm labor
 Fetal and maternal pathology
 Physiological concerns

What is Prematurity?
Prematurity is defined as less than 37
weeks of gestation in humans
 Prior to 32 weeks is considered a very
premature birth
 Less than 28 weeks is extremely
premature

Preterm Labor


Birth prior to expected delivery date
Occurs for a variety of reasons
 early


rupture of fetal membranes
can lead to amnionitis
Methods to prevent labor
 stop
/delay onset of pre-mature births
 does not guarantee a healthy infant

Planned interventions to terminate pregnancy
 serious
maternal illness
 problems affecting fetal well being or growth
Preterm Labor

Preterm labor prevention:
 Social

measures
increasing awareness of risk factors negatively
impacting pregnancy
smoking and alcohol consumption
 sexually transmitted diseases

 Physical
measures
regular doctor visits throughout pregnancy
 uterine-activity monitoring
 bed rest
 cervical assessment

Preterm Labor

Preterm labor prevention (cont.)
 Surgical

measures
cervical cerclage (applying stitches)
 Pharmacological

agents
betamimetic drugs
stop uterine contractions in active labor
 most widely used among other labor-inhibiting agents


inhibitors of prostaglandin synthesis


strong and practical use in preventing labor
antibiotics

some use in preventing early labor in women with
bacterial vaginosis
Preterm Labor

Types of preterm births
 Antepartum
death
 Lethal malformations

fetal outcome cannot be changed, vitality of mother is
important
 Multiple

pregnancies
50% of all multiple pregnancies result in premature delivery
 Elective
deliveries
 Maternal and/or fetal pathology



preclampsia
antepartum hemorrhage
intra-uterine growth restriction
Antepartum death and lethal
malformations
10-15% of all premature births
 Almost 50% of total perinatal mortality
 This form is unsavable
 Infant dies before labor or has
malformations that are incompatible with
life (fetal termination of pregnancy)
 Maternal well-being is a large factor
 Ethical controversy on outcome

Multiple Pregnancy
Any pregnancy involving more than one
fetus
 Almost half of multiple births occur
prematurely
 Multiple births are 15 times more likely to
be associated with premature delivery
 Multiple births make up 20% of all
premature cases

Elective Delivery
Planned obstetric decision
 Complications during pregnancy within the
mother or the fetus
 Not necessarily premature infants

 have
to be less than 37 weeks in gestation
Maternal and Fetal Pathology

Preeclampsia
 more

severe eclampsia
Antepartum hemorrhage
 placental
abruption
 placental previa
Intra-uterine growth restriction
 Spontaneous preterm labor

Preeclampsia




Mother develops high blood pressure during
pregnancy (>140/90 mmMg)
At risk 28 weeks gestation – 48 hours postpartum
Symptoms include proteinuria, headaches, trouble
with vision, upper abdominal pain, nausea and
vomiting, decreased urination, thrombocytopenia,
decrease liver function, and difficulty breathing
Unnoticed mother at risk of eclampsia
 seizures or self-induced coma
Antepartum Hemorrhage
Bleeding from the birth canal (>20 weeks)
 Placental abruption


placenta separates from uterine wall
 blood pools between placental and
endometrium

Placental previa
 placental
attaches to lower uterus, covers
opening of cervix
 worsens as pregnancy progresses
Intra-uterine Growth Restriction




Placenta develops abnormally= less room for the
fetus to grow
Fetus is smaller than normal while the cranium
and feet are normal size
Symmetric and asymmetric
Low birth weight, sensitivity to vaginal delivery, hypoxia,
hypoglycemia, decreased immune function, depressed
thermoregulation, higher than normal red blood cell
count, increased chance of meconium staining, and a low
APGAR
Spontaneous Preterm Labor

Premature labor with no expected cause
Route for Delivery




Vaginal or Cesarean Section
Breech much more common in preterm when
unplanned
Safer for premature infants to use C-section
depending on how far along in gestation
Premature baby is more susceptible to
compress from the pelvic region than a term
baby
 they
have a softer skull

Cow c-section
video:

https://www.youtube.com/wa
tch?v=oAqM505ZsFI
Preterm Birth

Physiological consequences
 infant’s
body systems are not prepared to
function on their own
 numerous conditions that result from
prematurity can be treated
 depending upon extent of prematurity,
morbidity rate may be high
Preterm Birth

Preterm birth is the leading cause of neonatal
mortality
 lack
of development of body systems is underlying
cause

Concerns:
 increased
morbidity and mortality
 intraventricular hemorrhage (IVH)
 periventricular leukomalacia (PVL)
 cerebral palsy
 necrotizing enterocolitis (NEC)
 retinopathy of prematurity (ROP)
 respiratory distress syndrome (RDS)
Neurological Concerns

Intraventricular hemorrhage (IVH)
 blood

vessels of brain not fully developed
bleeding in ventricles of the brain
 premature
infants at a much higher risk (>10
weeks early)
 occurs after birth within the first couple of days of
life
 not preventable
 increase risk if other problems

Hydrocephalus
 fluid
accumulation in the brain
Neurological

Periventricular leukomalacia (PVL)

softening in the white matter of the ventricles
 severe damage or death to this part of the
brain
 born >10 weeks early, babies with IVH more
likely to experience PVL
 hypoxia or uterine infection during gestation
 no treatment
 can cause cerebral palsy
Respiratory
Respiratory distress syndrome (RDS)
 Over 50% of premature infants
 Pulmonary surfactant produced during late
pregnancy
 Use different techniques to speed up
pulmonary maturation or assist lung
function- corticosteriods

 betamethasone
and dexamethasone
Gastrointestinal and Metabolism
Immature digestive system= abnormal
digestion and reaction to the diet
 Necrotizing enterocolitis (3-7d after birth)

 cells
in bowel are injured become inflammed
 cells spontaneous necrose
 infants fed only breast milk have lower risk
 surgically treated by removing dead tissue
 withdrawn
feedings
Immunity
Compromised immune system= prolonged
time in the NICU
 Lower levels of IGg & delayed
development of innate immune response
 Passive transfer across the placenta
occurs during third trimester
 Neutropenia at birth

Renal System
Decreased ability to maintain blood
pressure
 Difficult time regulating electrolyte and
water balance
 Glomeruli and tubules in the kidney that
are responsible for blood filtration and
urine secretion are not fully functionally
until 6 weeks of age in full term babies

Thermoregulation
Less brown fat stores
 At high risk to hypothermia

 leads
to breathing problems and low blood
glucose

Use available energy for heat
 hypoglycemia
 decreased
stores of glycogen
 lower rates of grain and slow development
after birth
Preterm Birth in Cattle
Abortions- 42-260 days of gestation
 Preterm birth >260 days

 concern
for producers when incidence is over 35% in herd
 viral (BVD, IBR)
 bacterial infection
 genetic defects
 heat stress- hypoxia, hypotension and acidosis
 toxins in feed
Ponderosa pine needles
 zearalenone (moldy forages)

(Hovingh, 2009)
Prevention of Preterm Birth Cattle
Routine pregnancy checks
 Following vaccine protocol specific to herd

 administering

at appropriate times
Clean breeding techniques
 AI
techs and ov/estrous sync (CIDRs)
 bull soundness exams (virgin bulls preferred)

Heat abatement
 especially

dry cows and prefresh pens
Proper nutrition management
Take home messages
The health and well being of the mother
greatly effects the health of the fetus and
can increase the risk of premature labor
 The level of prematurity depends on how
early birth occurs

 the
more premature= more
development/health concerns

Some conditions are not treatableprevention is key
References
Folkerth, R.D. 2006. Periventricular Leukomalacia: Overview and Recent Findings.
Pediatric and Developmental Pathology 9(1):3-13. doi:10.2350/06-01-0224.1
Gilliam, M., D. Rosenberg, and F. Davis. 2002. The Likelihood of Placenta Previa With
Greater Number of Cesarean Deliveries and Higher Parity. Obstetrics and
Gynecology 99(6):976-980.
Gubhaju, L., M.R. Sutherland, and M.J. Black. 2011. Preterm Birth and the Kidney:
Implications for Long-Term Renal Health. Reproductive Sciences 18(4):322-333.
doi:10.1177/1933719111401659
Henry, D.L., T.F. McElrath, and N.A. Smith. 2013. Preterm Severe Preeclampsia in
Singleton and Twin Pregnancies. Journal of Perinatology 33:94-97. doi:
10.1038/jp.2012.74
Hovingh, E. 2009. Abortions in Dairy Cattle (Virginia Cooperative Extension). http://
pubs.ext.vt.edu/404/404-288/404-288.html
Kaneshiro, N.K. 2014. Premature Infant (A.D.A.M. Medical Encyclopeda).
http://www.nlm.nlh..gov/medlineplus/ency/article/001562.htm (Accessed 3
March 2016).
Kendig, J.W., and U. Nawab. 2015. Necrotizing Entercolitis (Merck Manual)
http://www.merckmanuals.com/professionalpediatrics/perinatal-problems/
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References (cont.)
Linder, N., O. Haskin, O. Levit, G. Klinger, T. Prince, N. Naor, P. Turner, B. Karmazyn, and L. Sicota.
2007. Risk Factors for Intraventricular Hemorrhage in Very Low Birth Weight Premature
Infants: A Retrospective Case-Control Study. Pediatrics 111(5):590-595.
Magann, E.F., D.A. Doherty, K. Turner, G.S. Lanneau, J.C. Morrison, and J.P. Newnham. 2007.
Second Trimester Placental Location as a Predictor of Adverse Pregnancy Outcome.
Journal of Perinatology 27:9-4. doi:10.1038/sj.jp.7211621
Melville, J.M., and T.J. Moss. 2013. The Immune Consequences of Preterm Birth. Frontiers and
Neuroscience 7(79) doi:10.3389/fnins.2013.
Papile, L., G. Munsick-Bruno, and A. Schaefer. 1983. Relationship of Cerebral Intraventricular
Hemorrhage and Early Childhood Neurologic Handicaps. Journal of Pediatrics 103(2):
273-277.
Redman, C., and I.L. Sargent. 2005. Latest Advances in Understanding Preeclmampsia. Science
308(5728):1592-1594. doi:10.1126/science.1111726
Reshink, R. 2002. Intrauterine Growth Restriction. Obstetrics & Gynecology 99(3):490-496.
Woolston, M.S. 2016. Premature Births on the Rise (Health Day). http://consumer.healthday.com/
encyclopedia/pregnancy-33/pregnancy-news- 543/premature-births-on-therise643869.html (Accessed 6 March 2016).
Zohdi, V., L. Kyungjoon, J.T. Pearson, and M.T. Black. 2015. Developmental Programming of
Cardiovascular Disease Following Intrauterine Growth Restriction: Findings Utilizing a Rat
Model of Maternal Protein Restriction. Nutrients 7(1):19-152. doi:10.3390/nu7010119
Questions?