Obstetrics Flashcards
What is Pre-eclampsia
Pre-eclampsia refers to new high blood pressure (hypertension) in pregnancy with end-organ dysfunction, notably with proteinuria (protein in the urine). It occurs after 20 weeks gestation, when the spiral arteries of the placenta form abnormally, leading to a high vascular resistance in these vessels.
Pre-eclampsia features a triad of:
- Hypertension
- Proteinuria
- Oedema
Pre-eclampsia is a significant cause of maternal and fetal morbidity and mortality. Without treatment, it can lead to
maternal organ damage, fetal growth restriction, seizures, early labour and in a small proportion, death.
What is Eclampsia
Eclampsia is when seizures occur as a result of pre-eclampsia.
Patho of Pre-eclampsia
When the blastocyst implants on the endometrium, the outermost layer, called the syncytiotrophoblast, grows into the endometrium. It forms finger-like projections called chorionic villi. The chorionic villi contain fetal blood vessels.
Trophoblast invasion of the endometrium sends signals to the spiral arteries in that area of the endometrium, reducing their vascular resistance and making them more fragile. The blood flow to these arteries increases, and eventually they break down, leaving pools of blood called lacunae (lakes). Maternal blood flows from the uterine arteries, into these lacunae, and back out through the uterine veins. Lacunae form at around 20 weeks gestation.
When the process of forming lacunae is inadequate, the woman can develop pre-eclampsia. Pre-eclampsia is caused by high vascular resistance in the spiral arteries and poor perfusion of the placenta. This causes oxidative stress in the placenta, and the release of inflammatory chemicals into the systemic circulation, leading to systemic inflammation and impaired endothelial function in the blood vessels.
Risk Factors for Pre-Eclampsia
High-risk factors are:
- Pre-existing hypertension
- Previous hypertension in pregnancy
- Existing autoimmune conditions (e.g. systemic lupus erythematosus)
- Diabetes
- Chronic kidney disease
Moderate-risk factors are:
- Older than 40
- BMI > 35
- More than 10 years since previous pregnancy
- Multiple pregnancy
- First pregnancy
- Family history of pre-eclampsia
Women are offered _____ from 12 weeks gestation until birth if they have one high-risk factor or more than one moderate-risk factors for pre-eclampsia
Women are offered aspirin from 12 weeks gestation until birth if they have one high-risk factor or more than one moderate-risk factors.
Pre-eclampsia has symptoms of the complications:
- Headache
- Visual disturbance or blurriness
- Nausea and vomiting
- Upper abdominal or epigastric pain (this is due to liver swelling)
- Oedema
- Reduced urine output
- Brisk reflexes
Diagnosis of Pre-eclampsia
The NICE guidelines (2019) advise a diagnosis can be made with a:
- Systolic blood pressure above 140 mmHg
- Diastolic blood pressure above 90 mmHg
PLUS any of:
- Proteinuria (1+ or more on urine dipstick)
- Organ dysfunction (e.g. raised creatinine, elevated liver enzymes, seizures, thrombocytopenia or haemolytic anaemia)
- Placental dysfunction (e.g. fetal growth restriction or abnormal Doppler studies)
Proteinuria in pregnancy can be quantified using:
- Urine protein:creatinine ratio (above 30mg/mmol is significant)
- Urine albumin:creatinine ratio (above 8mg/mmol is significant)
NICE recommends using placental growth factor PlGF between __ and __ weeks gestation to rule-out pre-eclampsia.
NICE recommends using PlGF between 20 and 35 weeks gestation to rule-out pre-eclampsia
All pregnant women are routinely monitored at every antenatal appointment for evidence of pre-eclampsia, with:
Blood pressure
Symptoms
Urine dipstick for proteinuria
When gestational hypertension (without proteinuria) is identified, the general management involves:
- Treating to aim for a blood pressure below 135/85 mmHg
- Admission for women with a blood pressure above 160/110 mmHg
- Urine dipstick testing at least weekly
- Monitoring of blood tests weekly (full blood count, liver enzymes and renal profile)
- Monitoring fetal growth by serial growth scans
- PlGF testing on one occasion
When pre-eclampsia is diagnosed, the general management is similar to gestational HTN to gestational hypertension, except:
- Scoring systems are used to determine whether to admit the woman (fullPIERS or PREP‑S)
- Blood pressure is monitored closely (at least every 48 hours)
- Urine dipstick testing is not routinely necessary (the diagnosis is already made)
- Ultrasound monitoring of the fetus, amniotic fluid and dopplers is performed two weekly
Medical management of pre-eclampsia is with:
- Labetolol is first-line as an antihypertensive
- Nifedipine (modified-release) is commonly used second-line
- Methyldopa is used third-line (needs to be stopped within two days of birth)
- Intravenous hydralazine may be used as an antihypertensive in critical care in severe pre-eclampsia or eclampsia
- IV magnesium sulphate is given during labour and in the 24 hours afterwards to prevent seizures
- Fluid restriction is used during labour in severe pre-eclampsia or eclampsia, to avoid fluid overload
What can be given o women having a premature birth to help mature the fetal lungs.
Corticosteroids
What happens if pre-eclampsia can not be controlled
Planned early birth
What is used to managed seizures in Eclampsia
. IV magnesium sulphate is used to manage seizures associated with pre-eclampsia.
complication of pre-eclampsia and eclampsia
HELLP
Haemolysis
Elevated Liver enzymes
Low Platelets
What is Gestational Diabetes
Gestational diabetes refers to diabetes triggered by pregnancy. It is caused by reduced insulin sensitivity during pregnancy, and resolves after birth.
What are common complications from gestational diabetes
The most significant immediate complication of gestational diabetes is a large for dates fetus and macrosomia.
This has implications for birth, mainly posing a risk of shoulder dystocia
. Longer-term, women are at higher risk of developing type 2 diabetes after pregnancy.
WHat should be the investigation for anyone with risk factors for gestational diabetes?
oral glucose tolerance test at 24 – 28 weeks gestation. Women with previous gestational diabetes also have an OGTT soon after the booking clinic.
RF for gestational Diabetes
The NICE guidelines (2015) list the risk factors that warrant testing for gestational diabetes:
- Previous gestational diabetes
- Previous macrosomic baby (≥ 4.5kg)
- BMI > 30
- Ethnic origin (black Caribbean, Middle Eastern and South Asian)
- Family history of diabetes (first-degree relative)
OGTT should be given to a pregant lady if:
Large for dates fetus
Polyhydramnios (increased amniotic fluid)
Glucose on urine dipstick