Week 4 Flashcards
Para (P)
Refers to the number of times the woman has given birth after 24 weeks gestation, regardless of whether the foetus was alive or stillborn
Primiparous
technically refers to a patient that has given birth after 24 weeks gestation once before
Multiparous
Refers to a patient that has given birth after 24 weeks gestation two or more times
A pregnant woman with three previous deliveries at term
G4 P3
A non-pregnant woman with a previous birth of healthy twins
G1 P1
A non-pregnant woman with a previous miscarriage
G1 P0 + 1
A non-pregnant woman with a previous stillbirth (after 24 weeks gestation):
G1 P1
There are two vaccines offered to all pregnant women
- Whooping cough (pertussis) from 16 weeks gestation
2. Influenza (flu) when available in autumn or winter
Obstetricians describe the position of the baby’s head in relation to the mother’s ischial spines during the descent phase. Descent is measured in centimetres, from:
-5: when the baby is high up at around the pelvic inlet
0: when the head is at the ischial spines (this is when the head is “engaged”)
+5: when the foetal head has descended further out
Risks of prolonged and delayed delivery of placenta in labour
Haemorrhage, or more than a 60-minute delay in delivery of the placenta, should prompt active management. Active management can be associated with nausea and vomiting.
How does suckling ensure milk production?
Suckling reduces dopamine release → increases prolactin release
Strength and duration of suckling determines amount of prolactin released
This determines amount of milk available for subsequent feeds
When is prolactin produced in pregnancy?
Prolactin - stimulates milk production
Prolactin secreted from 16 weeks but breast tissue unresponsive - steroid block
What hormones block the response of breast tissue to prolactin before birth?
Progesterone and oestrogen remains high until delivery of placenta → where lactation can occur - After birth oestrogen and progesterone unblocks the response to prolactin from breast tissue - so prolactin drops in level as it doesn’t need to remain high - just steady level
There are typically two (and sometimes three) ultrasounds performed during in pregnancy
Dating scan – typically 8-9 weeks – if dates are uncertain (NIPT usually performed)
Combined screening test – USS and blood test performed between 11 and 13 weeks
Foetal structural abnormality scan – performed at 18-20 weeks
The combined screening test
should be offered to all pregnancy women. This is a test performed around 12 weeks of gestation (quoted ins one places as between 11 weeks and 2 days and 13 weeks and 6 days)
What does the combined screening test screen for?
>
Down Syndrome – trisomy 21 Edward’s syndrome – trisomy 18 Patau’s syndrome – trisomy 13
False positive rate – <5% (I.e. specificity of >95%)
Sensitivity – 85%
Amniocentesis
– if >15 weeks gestation
In this procedure, a needle is passed, usually under USS guidance, into the amniotic fluid, and roughly 10-20ml of fluid is aspirated (1ml for every week of gestation)
> Contains samples from fetal skin, urinary tract and lungs
When can amniocentesis be performed?
– if >15 weeks gestation
Complications of amniocentesis
Miscarriage rate = 0.5-1% Amniotic fluid leakage – 3% Uterine bleeding – 2% Maternal rhesus sensitisation Sepsis (rare)
Volume of distribution
equals the total amount of drug in the body / drug blood plasma concentration
Teratogenic drugs
> ACE inhibitors/ARB > Androgens > Antiepileptics > Cytotoxics > Lithium > Methotrexate > Retinoids > Warfarin
Adverse effects of drugs on labour abd the baby around term time
Progress of labour Premature closure of ductus arteriosus Opiates – respiratory depression Bleeding with Warfarin Withdrawal syndrome with opiates & SSRIs Sedation
Adverse effects of drugs on foetus in 1st trimester
Risk of early miscarriage
Organogenesis
Period of greatest teratogenic risk
Avoid drugs if at all possible unless maternal benefit outweighs risk to foetus
BP control in pregnancy (prescribed drugs)
BP falls during 2nd trimester If need to treat, use one of: o Labetalol o Methyldopa o (Nifedipine MR) Avoid ACE inhibitors / ARB Beta blockers may inhibit foetal growth in late pregnancy
UTI management of pregnant woman
follow local guidelines
Nitrofurantoin, cefalexin, (3rd trimester – trimethoprim)
Heartburn management in pregnancy
Antacids
Nausea and vomiting management in pregnancy
Cyclizine safest
All pregnant women should be assessed for risk of VTE, Those with significant risk factors should receive thromboprophylaxis with LMWH; what are these risk factors?
o 2 or more risk factors e.g obesity, age>35yrs, smoking, para >3, previous DVT, Caesarean delivery
o LMWH should be given at delivery and up to 7 days post-partum
What complications does phenytoin cause in pregnant women?
causes cleft lip and palate
What complications does amiodarone cause in breastfeeding mothers?
neonatal hypothyroidism
What complications does cytotoxics cause in breastfeeding mothers?
bone marrow suppression
What complications does benzodiazepines cause in breastfeeding mothers?
drowsiness
Nutrition and supplement advice in pregnancy
400 micrograms Folic acid pre-conception & first trimester (5mg in diabetics and on anti-epileptics)
10 micrograms Vitamin D through pregnancy & continuation if breast feeding
Not eating for two!
Optimal weight desired pre-conception
Calories advice in pregnancy
Calories: increase 70 kcal/day in the first trimester to 260 and 500 kcal/day in the second and third, respectively), with an increase of about 500 kcal/day during the first 6 months of exclusive breastfeeding
Protein intake advice in pregnancy
Recommended daily allowances should be increased by 1 g/day in the first trimester of gestation, 8 g/day in the second trimester, and 26 g/day in the third trimester
Fetal Risks of vitamin d deficiency during pregnancy
SGA, Neonatal Hypocalcaemia ,Asthma/Respiratory Infection, Rickets
Foods to avoid in pregnancy
- Soft cheese
- Undercooked meat, cured meats, game
- Tuna
- Raw/partially cooked eggs
- Pate
- Liver
- Vitamin & Fish Oil Supplements
What group of pregnant women are required to take 5mg of folic acid instead of the normal 400micrograms?
obese women, diabetic patients, history of baby with NTD or FH, on anti-epileptics
Sources of iron
Legumes
dark green vegetables
wholemeal bread
eggs (for vegetarians who include them in their diet)
fortified breakfast cereals (with added iron)
dried fruit, such as apricots
Large for gestational age
Babies are defined as being large for gestational age (also known as macrosomia) when the weight of the newborn is more than 4.5kg at birth. During pregnancy, an estimated fetal weight above the 90th centile is considered large for gestational age.
Causes of large for gestational age (macrosomia)
- Constitutional
- Maternal diabetes (gestational)
- Previous macrosomia
- Maternal obesity or rapid weight gain
- Overdue
- Male baby
Risks of macrosomia to the mother
- Shoulder dystocia
- Failure to progress
- Perineal tears
- Instrumental delivery or caesarean
- Postpartum haemorrhage
- Uterine rupture (rare)
Risks of macrosomia to the baby
- Birth injury (Erbs palsy, clavicular fracture, fetal distress and hypoxia)
- Neonatal hypoglycaemia
- Obesity in childhood and later life
- Type 2 diabetes in adulthood
Important points to remember about macrosomia
If you only remember two things about macrosomia, remember that it is caused by gestational diabetes, and there is a significant risk of shoulder dystocia during birth.
Investigations for a large for gestational age baby are:
- Ultrasound to exclude polyhydramnios and estimate the fetal weight
- Oral glucose tolerance test for gestational diabetes
Polyhydramnios
The excessive accumulation of amniotic fluid — the fluid that surrounds the baby in the uterus during pregnancy.
Polyhydramnios symptoms
Abdominal discomfort Pre-labour rupture of membranes Preterm labour Cord prolapse LFD Malpresentation tense shiny abdomen inability to feel fetal parts
Diagnosis of Polyhydramnios
>
Ultrasound Confirmation AFI >25 DVP >8cm
Twin-To- Twin Transfusion Syndrome (TTTS)
Syndrome with artery-vein anastomoses. Donor twin perfuses the recipient twin.
Diagnosis of Twin-To- Twin Transfusion Syndrome (TTTS)
Oligohydramnios- polyhydramnios (Oly-Poly)
Complications of Twin-To- Twin Transfusion Syndrome (TTTS)
>
Mortality >90% with no treatment
> Neurological morbidity 37% and high in surviving twin if IUD
Management of Twin-To- Twin Transfusion Syndrome (TTTS)
>
Before 26/40 – Rx fetoscopic laser ablation >26/40- amnioreduction /septostomy Deliver 34-36/40
Diabetes in pregnancy: Complications
- Pre eclampsia
- Polyhydramnios
- Macrosomia
- Shoulder dystocia- 10% risk vs 1% in general population
- Neonatal hypoglycaemia
Gestational diabetes
o Usually diagnosed in third trimester (24 to 28 weeks )
o In some women diabetes diagnosed in the first trimester- they probably had diabetes before they got pregnant – and it won’t go away after giving birth
Diabetes HBA1C targets in pregnancy
o HBA1C Monitoring Aim for 48mmol/mol (6.5%)
o Avoid pregnancy if HBA1C above 86 mmol/mol (10%)
The main risk with a large for gestational age baby
shoulder dystocia - when the baby’s head has been born but one of the shoulders becomes stuck behind the mother’s pubic bone, delaying the birth of the baby’s body
Small for gestational age (SGA)
Small for gestational age (SGA) = infant born with birth weight below 10th centile Abdominal circumference (AC) or estimated foetal weight (EFW) below 10th centile by ultrasound scan
Fetal growth restriction (FGR)
Failure to achieve genetic potential for growth, implies pathological restriction of genetic growth potential
Placental causes of SGA
o Infarcts
o Abruption
o Often secondary to hypertension
Foetal causes of SGA
o Infection e.g. rubella, CMV, toxoplasma
o Congenital anomalies e.g. absent kidneys
o Chromosomal abnormalities e.g. Down’s syndrome
Maternal causes of SGA
o Smoking o Alcohol o Drugs o Height and weight o Age o Maternal disease e.g. hypertension
SGA diagnosis
- Ultrasound measurement of AC and calculation of EFW
- Measurements plotted on centile chart
- Various charts available
Management of SGA
For women being cared for by a midwife with no pre-existing factors prompting obstetric input
> Measurement of symphysis-fundal height (SFH) at each visit from 24 weeks
> Plotted on growth chart
> Single measurement below 10th centile prompts referral for serial scans for growth
Severe SGA
When the fetus is below the 3rd centile for their gestational age. Low birth weight is defined as a birth weight of less than 2500g.
The causes of SGA can be divided into two categories: what are they?
- Constitutionally small, matching the mother and others in the family, and growing appropriately on the growth chart
- Fetal growth restriction (FGR), also known as intrauterine growth restriction
Difference between SGA and FGR
SGA simply means that the baby is small for the dates, without stating why. The fetus may be constitutionally small, growing appropriately, and not at increased risk of complications. Alternatively, the fetus may be small for gestational age due to pathology (i.e. FGR), with a higher risk of morbidity and mortality.
The causes of fetal growth restriction (FGR) can be divided into two categories: what are they?
- Placenta mediated growth restriction
* Non-placenta mediated growth restriction, where the baby is small due to a genetic or structural abnormality
Placenta mediated growth restriction causes
Refers to conditions that affect the transfer of nutrients across the placenta: • Idiopathic • Pre-eclampsia • Maternal smoking • Maternal alcohol • Anaemia • Malnutrition • Infection • Maternal health conditions
Non-placenta medicated growth restriction causes
- Genetic abnormalities
- Structural abnormalities
- Fetal infection
- Errors of metabolism
Short term complications of fetal growth restriction (FGR) include
- Fetal death or stillbirth
- Birth asphyxia
- Neonatal hypothermia
- Neonatal hypoglycaemia
SGA Low-risk women management
Low-risk women have monitoring of the symphysis fundal height (SFH) at every antenatal appointment from 24 weeks onwards to identify potential SGA. The SFH is plotted on a customised growth chart to assess the appropriate size for the individual woman. If the symphysis fundal height is less than the 10th centile, women are booked for serial growth scans with umbilical artery doppler.
SGA high-risk women management
- Estimated fetal weight (EFW) and abdominal circumference (AC) to determine the growth velocity
- Umbilical arterial pulsatility index (UA-PI) to measure flow through the umbilical artery
- Amniotic fluid volume
When is early delivery considered in SGA?
Considered when growth is static on the growth charts, or other problems are identified (e.g. abnormal Doppler results). This reduces the risk of stillbirth.
Corticosteroids are given when delivery is planned early, particularly when delivered by caesarean section.
Seatbelt advice in pregnancy
Place car seatbelts above and below the bump (not across it)
What is the risk of flying in pregnancy?
Flying increases the risk of venous thromboembolism (VTE)
Complications of alcohol intake in early pregnancy
- Miscarriage
- Small for dates
- Preterm delivery
- Fetal alcohol syndrome
Fetal alcohol syndrome
Refers to certain characteristics that can occur in children of mothers that consumed alcohol during pregnancy.
Fetal alcohol syndrome features
- Microcephaly (small head)
- Thin upper lip
- Smooth flat philtrum (the groove between the nose and upper lip)
- Short palpebral fissure (short horizontal distance from one side of the eye to the other)
- Learning disability
- Behavioural difficulties
- Hearing and vision problems
- Cerebral palsy
Management of hypothyroidism in pregnancy
Hypothyroidism is treated with levothyroxine (T4). Levothyroxine can cross the placenta and provide thyroid hormone to the developing fetus. The levothyroxine dose needs to be increased during pregnancy, usually by at least 25 – 50 mcg (30 – 50%). Treatment is titrated based on the TSH level, aiming for a low-normal TSH level.
Management of rheumatoid arthritis in pregnancy
- Methotrexate is contraindicated
- Hydroxychloroquine is considered safe during pregnancy and is often the first-line choice
- Sulfasalazine is considered safe during pregnancy
- Corticosteroids may be used during flare-ups
Rubella in pregnancy
Rubella is also known as German measles. Congenital rubella syndrome is caused by maternal infection with the rubella virus during the first 20 weeks of pregnancy. The risk is highest before ten weeks gestation.
Rubella and the MMR vaccine in pregnant women
Women planning to become pregnant should ensure they have had the MMR vaccine.
Pregnant women should not receive the MMR vaccination, as this is a live vaccine.
Non-immune women should be offered the vaccine after giving birth.
Chickenpox in pregnancy complications
- More severe cases in the mother, such as varicella pneumonitis, hepatitis or encephalitis
- Fetal varicella syndrome
- Severe neonatal varicella infection (if infected around delivery)
Management of pregnant women with chickenpox
- When they are not sure about their immunity, test the VZV IgG levels. If positive, they are safe.
- When they are not immune, they can be treated with IV varicella immunoglobulins as prophylaxis against developing chickenpox. This should be given within ten days of exposure.
When the chickenpox rash starts in pregnancy, they may be treated with oral aciclovir if they present within 24 hours and are more than 20 weeks gestation.
Congenital varicella syndrome
occurs in around 1% of cases of chickenpox in pregnancy. It occurs when infection occurs in the first 28 weeks of gestation.
Congenital varicella syndrome features
- Fetal growth restriction
- Microcephaly, hydrocephalus and learning disability
- Scars and significant skin changes located in specific dermatomes
- Limb hypoplasia (underdeveloped limbs)
- Cataracts and inflammation in the eye (chorioretinitis)
Listeriosis in pregnant women complications
Listeriosis in pregnant women has a high rate of miscarriage or fetal death. It can also cause severe neonatal infection.
Listeria transmission in pregnancy
Listeria is typically transmitted by unpasteurised dairy products, processed meats and contaminated foods. Pregnant women are advised to avoid high-risk foods (e.g. blue cheese) and practice good food hygiene.
Congenital cytomegalovirus infection in pregnancy
occurs due to a cytomegalovirus (CMV) infection in the mother during pregnancy. The virus is mostly spread via the infected saliva or urine of asymptomatic children. Most cases of CMV in pregnancy do not cause congenital CMV.
There is a classic triad of features in congenital toxoplasmosis:
- Intracranial calcification
- Hydrocephalus
- Chorioretinitis (inflammation of the choroid and retina in the eye)
Congenital Toxoplasmosis
Infection with the Toxoplasma gondii parasite is usually asymptomatic. It is primarily spread by contamination with faeces from a cat that is a host of the parasite. When infection occurs during pregnancy, it can lead to congenital toxoplasmosis. The risk is higher later in the pregnancy.
Parvovirus B19
Parvovirus B19 infection typically affects children. It is also known as fifth disease, slapped cheek syndrome and erythema infectiosum. It is caused by the parvovirus B19 virus. The illness is self-limiting, and the rash and symptoms usually fade over 1 – 2 weeks.
Infections with parvovirus B19 in pregnancy can lead to several complications, particularly in the first and second trimesters. Complications are:
- Miscarriage or fetal death
- Severe fetal anaemia
- Hydrops fetalis (fetal heart failure)
- Maternal pre-eclampsia-like syndrome
Women suspected of parvovirus infection need tests for:
- IgM to parvovirus, which tests for acute infection within the past four weeks
- IgG to parvovirus, which tests for long term immunity to the virus after a previous infection
- Rubella antibodies (as a differential diagnosis)
Zika virus management in pregnancy
Pregnant women that may have contracted the Zika virus should be tested with viral PCR and antibodies to the Zika virus. Women with a positive result should be referred to fetal medicine for close monitoring of the pregnancy. There is no treatment for the virus.
The zika virus
The zika virus is spread by host Aedes mosquitos in areas of the world where the virus is prevalent. It can also be spread by sex with someone infected with the virus. It can cause no symptoms, minimal symptoms, or a mild flu-like illness. In pregnancy, it can lead to congenital Zika syndrome.
What are some situations anti-D injections are given (rhesus negative mothers with rhesus positive baby)?
- Antepartum haemorrhage
- Amniocentesis procedures
- Abdominal trauma
Anti-D injections are given routinely on two occasions:
28 weeks gestation
Birth (if the baby’s blood group is found to be rhesus-positive)
The Kleihauer test
The Kleihauer test checks how much fetal blood has passed into the mother’s blood during a sensitisation event. This test is used after any sensitising event past 20 weeks gestation, to assess whether further doses of anti-D is required.
Diamniotic
two separate amniotic sacs
Monochorionic
share a single placenta
Dichorionic
two separate placentas
Monozygotic
identical twins (from a single zygote)
Dizygotic
non-identical (from two different zygotes)
Diagnosis of multiple pregnancy
Ultrasound is also used to determine the:
• Gestational age
• Number of placentas (chorionicity) and amniotic sacs (amnionicity)
• Risk of Down’s syndrome (as part of the combined test)
The lambda sign, or twin peak sign
refers to a triangular appearance where the membrane between the twins meets the chorion, as the chorion blends partially into the membrane. This indicates a dichorionic twin pregnancy (separate placentas).
The T sign
The T sign refers to where the membrane between the twins abruptly meets the chorion, giving a T appearance. This indicates a monochorionic twin pregnancy (single placenta).
Monochorionic diamniotic twins have what sign?
The T sign - refers to where the membrane between the twins abruptly meets the chorion, giving a T appearance. This indicates a monochorionic twin pregnancy (single placenta).
Twin Anaemia Polycythaemia Sequence
Twin anaemia polycythaemia sequence is similar to twin-twin transfusion syndrome, but less acute. One twin becomes anaemic whilst the other develops polycythaemia (raised haemoglobin).
Investigations in multiple pregnancy women
• Booking clinic ultrasounds
• 20 weeks gestation
• 28 weeks gestation
Additional ultrasound scans are required in multiple pregnancy to monitor for fetal growth restriction, unequal growth and twin-twin transfusion syndrome:
• 2 weekly scans from 16 weeks for monochorionic twins
• 4 weekly scans from 20 weeks for dichorionic twins
Monoamniotic twins delivery management
require elective caesarean section at between 32 and 33 + 6 weeks.
Diamniotic twins delivery management
(aim to deliver between 37 and 37 + 6 weeks):
• Vaginal delivery is possible when the first baby has a cephalic presentation (head first)
• Caesarean section may be required for the second baby after successful birth of the first baby
• Elective caesarean is advised when the presenting twin is not cephalic presentation
UTI in pregnancy
Lower urinary tract infection involves infection in the bladder, causing cystitis (inflammation of the bladder). Upper urinary tract infection involves infection up to the kidneys, called pyelonephritis.
Pregnant women are at higher risk of developing lower urinary tract infections and pyelonephritis.
The risk of UTIs in pregnancy
Urinary tract infections in pregnant women increase the risk of preterm delivery. They may also increase the risk of other adverse pregnancy outcomes, such as low birth weight and pre-eclampsia.
Lower urinary tract infections present with:
- Dysuria (pain, stinging or burning when passing urine)
- Suprapubic pain or discomfort
- Increased frequency of urination
- Urgency
- Incontinence
- Haematuria
Pyelonephritis presents with:
- Fever (more prominent than in lower urinary tract infections)
- Loin, suprapubic or back pain (this may be bilateral or unilateral)
- Looking and feeling generally unwell
- Vomiting
- Loss of appetite
- Haematuria
- Renal angle tenderness on examination
Commonest causes of UTI in pregnancy
Most common cause of urinary tract infection is Escherichia coli (E. coli). This is a gram-negative, anaerobic, rod-shaped bacteria that is part of the normal lower intestinal microbiome. It is found in faeces, and can easily spread to the bladder.
Management of UTI in pregnancy
Urinary tract infection in pregnancy requires 7 days of antibiotics.
The antibiotic options are:
• Nitrofurantoin (avoid in the third trimester)
• Amoxicillin (only after sensitivities are known)
• Cefalexin
Why is nitrofurantoin avoided in the third trimester of pregnacy?
Nitrofurantoin needs to be avoided in the third trimester as there is a risk of neonatal haemolysis (destruction of the neonatal red blood cells).
Why is Trimethoprim avoided in the first trimester of pregnacy?
Trimethoprim needs to be avoided in the first trimester as it is works as a folate antagonist. Folate is important in early pregnancy for the normal development of the fetus. Trimethoprim in early pregnancy can cause congenital malformations, particularly neural tube defects (i.e. spina bifida). It is not known to be harmful later in pregnancy, but is generally avoided unless necessary.
