Antenatal Screening Flashcards
What proportion of pregnancies in Scotland are unplanned?
1/3
How does obesity affect pregnancy?
- Causes higher rate of poor outcomes including miscarriage and still birth
- Routine measurements of fundal height to monitor fetal growth and presentation may be impossible on abdominal palpation
- Venous thromboembolic events are more common in obese patients
How can alcohol affect pregnancy?
It is associated with fetal abnormalities causing a fetal alcohol syndrome which produces a typical facial appearance and affects learning
What general advice can be given to women pre-pregnancy?
•General health measures
- Improve diet
- Optimise BMI
- Reduce alcohol consumption
- Smoking cessation advice
- Take folic acid - helps prevent birth defects
- 400 mcg
- 5mg
How may age affect pregnancy?
- Pregnancy outcomes are poorer at both ends of the fertile population
- Teenagers may be socially deprived with lack of support, smoke more, and not receive the antenatal care they need, often booking late
- Older women, particularly the over 40s, are more prone to pre-existing medical conditions and develop complications of pregnancy such as gestational diabetes and hypertension
- Chromosomal disorders increase dramatically with advancing maternal age.
How may parity affect pregnancy?
- Pre-eclampsia is predominantly a condition of nulliparity, occurring in the first pregnancy
- Grand multiparity (4 or more deliveries) predisposes women to postpartum haemorrhage
How may occupation affect pregnancy?
- A patient’s occupation may expose them to situations that put either themselves or their fetus at risk
- They may have a very busy job with inadequate rest periods or be exposed to substances such as chemicals which cause fetal anomalies
How may substance misuse affect pregnancy?
- Substance misuse such has effects both on the mother who may not seek antenatal care or attend intermittently and on the fetus
- Heroin, methadone and benziodiazapines are addictive to the fetus and cause a withdrawal syndrome in the baby when it is cut off from its supply at birth
- Cocaine and crack are associated with abruption resulting in fetal death
- Women with substance misuse are seen in a specialist multidisciplinary clinic involving obstetricians, midwives, members of the substance misuse team (psychiatrists & CPNs), social workers and health visitors.
What advice regarding pre-existing medical conditions can be given to women pre-pregnancy?
•Optimise maternal health
-Diabetes (Pregnancy is advised against when the HbA1c is significantly elevated)
•Stop/Change any unsuitable drugs
-Good examples are chronic hypertension and epilepsy (Avoid ACE-I and sodium valproate)
•Advise regarding complications associated with maternal medical problems
- Worsening of maternal disease due to pregnancy
- Associated fetal abnormalities
•Occasionally advise against pregnancy
-Significant cardiac disease can be associated with maternal mortality (can only advise)
What is the relevance of phenylketonuria in pregnancy?
- Phenylketonuria is an inborn error of protein metabolism which causes an inability to metabolism essential amnio acid phenylalanine
- This results in high levels which causes mental developmental impairment
- It is screened for in newborn babies and amendable to treatment
- However if a woman with PKU is pregnant she needs to restart her low phenylalanine diet to prevent high levels reaching the developing fetal brain
What is the relevance of low thyroxine levels in pregnancy?
- The demand for thyroxine increases during pregnancy and therefore doses may need to be increased if mother has hypothyroidism
- Normal thyroxine levels are also required for fetal brain development.
What is the relevance of high thyroxine levels in pregnancy?
- A small number of women will be hyperthyroid entering pregnancy such as Graves disease
- They need treatment to keep their thyroid hormone levels normal
- Thyroid stimulating antibodies can cross the placenta to the foetus so the neonate will need to be checked as well
What are the risks associated with diabetes in pregnancy and how are they counteracted?
- Women with type 2 diabetes who are on oral hypoglyceamic medications need to be switched to insulin
- Diabetic patients are more at risk of pregnancy complications such as pre-eclampsia, stillbirth and macrosomic infants
- They should be cared for in a joint diabetic obstetric antenatal clinic
How are renal patients affected by their condition in pregnancy?
- Renal patients are more likely to develop pre-eclampsia which may be difficult to diagnose if they already have proteinuria and pre-existing hypertension
- Pregnancy is now possible for women who previously would not have been able to have children
- Renal transplantation restores fertility as well as renal function
How does epilepsy affect pregnancy?
- The main concern for women with epilepsy is the effect of their anti-epileptic medication on their developing fetus
- Sodium valproate is an effective drug but is associated with a higher rate of spina bifida in the offspring of women taking it
What are some maternal previous pregnancy problems and how are each of these conditions prevented?
- Pre-eclampsia - recommend aspirin 150mg during pregnancy and regular BP monitoring
- Gestational diabetes - HbA1C at booking and OGTT at 28 weeks
- Caesarian section - consider elective caesarian (may be fine if previous breech presentation)
- DVT or PE - consider antenatal thromboprophylaxis and 6 weeks postnatal treatment
What are some fetal previous pregnancy problems and how are each of these conditions prevented?
- Intrauterine growth restriction – recommend aspirin 150mg during pregnancy and serial ultrasound scans
- Preterm birth – consider transvaginal cervical length scans or cervical suture
