L14 Perinatal epidemiology Flashcards
1
Q
Define the perinatal period in developed countries.
A
22 weeks (154 days) of gestation to 7 completed days after birth.
2
Q
Read
Congenital anomalies
Occurrence Rate:
- 2% to 3% of babies are born with significant congenital birth defects.
- Major sites of significant congenital anomalies:
- Brain 10 per 1000 live births
- Heart 8 per 1000 live births
- Kidney 4 per 1000 live births
- Limbs 2 per 1000 live births
A
3
Q
Multiple births
- Increasing due to increasing ______ age and assisted reproductive technologies
- Increased mortality (chorionicity), cerebral palsy and developmental delay
A
Maternal
4
Q
List the health challenges to the foetus. (7)
A
- Abnormal placentation
- Poor nutrition
- Multiple births
- Congenital anomalies
- Premature delivery (<37 weeks)
- Low birth weight
- Fetal death (stillbirth)
5
Q
What is another phrase for congenital anomalies?
A
Birth defects
6
Q
Read
Congenital anomalies
Causes
- Genetics
- About 5% involve abnormalities of large portions or entire chromosomes
- Some anomalies arise from inheritance of abnormal genes (chromosomal anomalies)
- Others involve sporadic mutations in one of the germ cells contributing to the fetus. Sporadic mutations imply a low recurrence risk for future children
- Teratogenic exposures to the intrauterine environment of the fetus
- Dietary deficiencies. For example: dietary deficiency of maternal folic acid associated with an increased risk of spina bifida.
- Toxic effects. Exposure to harmful substances during pregnancy (e.g, mercury) or maternal drugs (e.g. thalidomide) can cause recognizable combinations of birth defects
- Some infections which a mother can contract during pregnancy, such as rubella and syphilis, can also affect the risk of the fetus developing congenital anomalies.
A
7
Q
Read
Preterm birth
- Affects 5-7% of pregnancies
- Shows familial aggregation
- Large ethnic variation (twice as common in African Americans compared to Caucasians)
- Interventions have had very limited success
- Outcomes of affected babies are improving, but causes remain largely unknown
- Genetic susceptibility factors believed to be important
Consequences of preterm birth
- Pulse pressure and gestational age
- Developmental delay
- Respiratory distress
- Importance of nutrition and early life programming
A
8
Q
Read
Stillbirth
- A stillbirth is a baby born dead after 24 completed weeks of pregnancy. If the baby dies before 24 completed weeks, it’s known as a miscarriage or late foetal loss.
- Around 5 per 1,000 births result in stillbirth.
- Stillbirth rates in most industrialised countries have declined over the past 20 years; rate appears to have reached a plateau in E & W.
- Concerns have been raised in relation to the lack of improvement in the rate of antepartum stillbirth, a large proportion of which are not attributed to any specific cause of death.
- The reasons for the recent lack of substantive decline in stillbirth rates are unknown, but may be related to changes in the distribution of risk factors (for example, greater numbers of births to very young and older women, increase in obesity and diabetes)
A
9
Q
Read
Perinatal death
- Number of stillbirths and deaths in the first week of life per 1,000 live births
- Indicator of obstetric care and deaths later in pregnancy, intrapartum, post- delivery
- Causes: PTB, LBW, respiratory distress syndrome, congenital anomalies, birth trauma/asphyxia (prolonged labour, hemorrhage, multiple pregnancies), infections (syphilis, HIV), sepsis (B hemolytic strep), hypothermia
A
10
Q
Read
Health Challenges to the Neonate
- Consequences of challenges to the fetus
- Neonatal death
- Cerebral palsy
- Infectious disease
- Respiratory Tract Infection
- Respiratory Syncitial Virus, Adenovirus
- Pneumonia
- Respiratory Tract Infection
- Infant death
- Sudden unexpected infant death
Neonatal death
- Deaths among live born infants prior to the first 28 days of life, per 1000 live births
- Early Neonatal mortality (ENMR) = deaths 0-6 days
- Late Neonatal mortality (LNMR) = deaths 7-28 days
- ~ 4 million deaths worldwide
- 38% of child deaths
- 75% in 1st week of life
- 99% in developing countries
- Main causes:
- Preterm birth (28%)
- Infections 26%
- Asphyxia 23%
- Tetanus 7%
Causes of Neonatal deaths
- Birth Outcomes (LBW, PTB, CA)
- Obstetric and neonatal complications (injury, asphyxia, hypothermia)
- Maternal Health preceding and during pregnancy
- Bacterial (e.g. meningitis) and viral infections (e.g. CMV)
- Neonatal infection is probably the major preventable cause of neonatal death in less developed countries
A
11
Q
Read
Cerebral palsy
- Umbrella term encompassing a group of non-progressive neurological disabilities in the development of human movement and posture.
- Arises from disturbance in the developing fetal brain.
- 2-2.5 per 1000 live births in developed countries
- No decline over the past 60 years.
- Occurs during pregnancy (75%) or after birth (25%)
- 80% causes unknown.
- Known causes include infections, malnutrition, head injury in early childhood
A
12
Q
Read
Respiratory tract infection
- RSV is the major cause of respiratory infection during infancy and childhood
- Annual epidemic in winter months.
- Peak incidence at age 3 -6 months
- Nearly all children infected by age 2-3 years
- Natural infection does not induce protective immunity
- Also causes pneumonia in young children
- Can cause bronchiolitis, requiring hospitalisation
- Ubiquitous so avoidance impossible, so vaccine is preferred solution, however none has been developed successfully
A
13
Q
Read
Sudden infant death
- Sudden infant death syndrome (SIDS) is any sudden and unexplained death of an apparently healthy infant aged one month to one year.
- Incidence 50 deaths per 100,000 births.
- Prenatal risks
- Inadequate prenatal care/nutrition
- Teenage pregnancy
- <1 year interval between births
- Smoking and Alcohol and drug abuse
- Post-natal risks
- Low birth weight (<1.5kg)
- Exposure to tobacco smoke
- Failure to breastfeed
- Excess clothing/overheating
- Gender (61% males)
- Age (high risk at 2-4 months, low after 1 year)
- Possible common aetiological factors in stillbirth and SIDS
A
14
Q
The ‘developmental origins of adult disease’ hypothesis (‘___1___ hypothesis’) states that adverse influences early in development and particularly during intrauterine life, can result in permanent changes in physiology and metabolism, which result in increased disease risk in ___2___.
A
- Barker
- Adulthood
15
Q
Multiple births are increasing due to what? (2)
A
- Increasing due to increasing maternal age and assisted reproductive technologies
- Increased mortality (chorionicity), cerebral palsy and developmental delay
