Teach Me ObGyn

Question 1

When is a baby defined as small for gestational age (SGA)?

Answer 1

an infant with a birth weight <10th centile for its gestational age
Severe SGA – a birth weight < 3rd centile

Question 2

What is fetal growth restriction?

Answer 2

when a pathological process has restricted genetic growth potential

can present with features of fetal compromise including reduced liquor volume (LV) or abnormal doppler studies

likelihood of FGR is higher in a severe SGA fetus.

Question 3

What is classed as a low birth weight?

Answer 3

an infant with a birth weight <2500g

Question 4

What can cause a baby to be SGA?

Answer 4

Normal (Constitutionally) Small:
ethnicity, sex, and parental height may contribute

Placenta Mediated Growth Restriction
(conditions that affect the transfer of nutrients across the placenta):
Pre-eclampsia, maternal smoking /alcohol, anaemia, malnutrition, infection

Non-Placenta Mediated Growth Restriction:
Growth is affected by fetal factors such as a chromosomal or structural anomaly, an error in metabolism or fetal infection

Question 5

What may suggest a constitutionally small v growth restricted baby on investigation?

Answer 5

The ratio of head circumference (HC) and AC:
a symmetrically small fetus is more likely to be constitutionally small whilst an asymmetrically small fetus is more likely to be caused by placental insufficiency

Placental insufficiency can result in impaired fetal kidney function which will result in reduced amniotic fluid volume

Question 6

Short term complications of fetal growth restriction?

Answer 6

Fetal death or stillbirth
Birth asphyxia
Neonatal hypothermia
Neonatal hypoglycaemia

Question 7

Risk factors for SGA?

Answer 7

Previous SGA baby
Smoking
Older mother (over 35 years)
Obesity, Diabetes
Existing hypertension , Pre-eclampsia
Multiple pregnancy
Low pregnancy‑associated plasma protein‑A (PAPPA)
Antepartum haemorrhage
Antiphospholipid syndrome

Question 8

What can be used for surveillance of SGA?

Answer 8

Women are booked for serial growth scans with umbilical artery doppler if they have:

Three or more minor risk factors
One or more major risk factors
Issues with measuring the symphysis fundal height (e.g. large fibroids or BMI > 35)

If UAD is normal induction can be offered at 37 weeks

Question 9

List some complications of SGA

Answer 9

stillbirth, birth asphyxia, hypothermia, obesity and cancer

Question 10

When is a baby defined as large for gestational age (LGA)?

Answer 10

an estimated fetal weight above the 90th centile during pregnancy is considered large for gestational age

OR when the weight of the newborn is more than 4.5kg at birth

Question 11

What can cause macrosomia?

Answer 11

Constitutional, Male baby, Overdue
Previous macrosomia
Maternal diabetes
Maternal obesity or rapid weight gain

Question 12

What are the risks of macrosomia to the mother ?

Answer 12

Shoulder dystocia
Failure to progress
Perineal tears
Instrumental delivery or caesarean
Postpartum haemorrhage
Uterine rupture (rare)

Question 13

What are the risks of macrosomia to the baby ?

Answer 13

Birth injury (Erbs palsy, clavicular fracture, fetal distress and hypoxia)
Neonatal hypoglycaemia
Obesity in childhood and later life
Type 2 diabetes in adulthood

Question 14

How should an LGA baby be investigated?

Answer 14

Ultrasound to exclude polyhydramnios and estimate the fetal weight
Oral glucose tolerance test for gestational diabetes

Question 15

How can risk be reduced when delivering an LGA baby?

Answer 15

Delivery on a consultant lead unit
Delivery by an experienced midwife or obstetrician
Access to an obstetrician and theatre if required
Active management of the third stage (delivery of the placenta)
Early decision for caesarean section if required
Paediatrician attending the birth

Question 16

In Rhesus D negative women, the administration of anti-D immunoglobulin should be considered following any sensitising event:

Answer 16

Invasive obstetric testing (e.g amniocentesis or chorionic villus sampling)
Antepartum haemorrhage (APH)
Ectopic pregnancy
ECV
Fall or abdominal trauma
Intrauterine death, miscarriage, termination of pregnancy
Delivery

Question 17

There are two main blood tests that should be considered following a rhesus sensitising event:

Answer 17

Maternal blood group and antibody screen – determines ABO and RhD blood groups, and detects any antibodies directed against RBC surface antigens

Feto-maternal haemorrhage test (Kleihauer test) - assesses how much fetal blood has entered the maternal circulation. If there has been a sensitising event after 20 weeks gestation, this test is used to determine how much anti-D immunoglobulin should be administered

Question 18

The WHO classify prematurity as:

Answer 18

Under 28 weeks: extreme preterm
28 – 32 weeks: very preterm
32 – 37 weeks: moderate to late preterm

Question 19

In women with a history of preterm birth (or an USS demonstrating a cervical length < 25mm before 24 weeks) there are two options of trying to delay birth:

Answer 19

Prophylactic vaginal progesterone: putting a progesterone suppository in the vagina to discourage labour
Prophylactic cervical cerclage: putting a suture in the cervix to hold it closed

Question 20

Where preterm labour is suspected or confirmed there are several options for improving the outcomes:

Answer 20

Tocolysis with nifedipine: nifedipine is a CCB that suppresses labour

Maternal corticosteroids: can be offered before 35 weeks gestation to reduce neonatal morbidity and mortality

IV Magnesium sulphate: can be offered before 34 weeks gestation and helps protect the baby’s brain

Delayed cord clamping or cord milking: can increase the circulating blood volume and haemoglobin in the baby

Question 21

Define post-term and post-dates pregnancy

Answer 21

Post-term pregnancy refers to a pregnancy extending past 42 weeks gestation (term refers to the 37-42 week gestation period)

Post-dates pregnancy refers to a pregnancy extending past the estimated delivery date (EDD), also known as due date at 40 weeks gestation.

Question 22

Risk factors for prolonged pregnancy?

Answer 22

Nulliparity
Maternal age >40
Previous prolonged pregnancy / fam hx
High BMI

Question 23

Complications of prolonged pregnancy?

Answer 23

increased risk of stillbirth

increased potential for placental insufficiency = higher risk of fetal acidaemia and meconium aspiration in labour, and the need for instrumental or caesarean delivery

Question 24

Define fetal lie

Answer 24

the relationship between the long axis of the fetus and the mother.
Longitudinal, transverse or oblique

Question 25

Define fetal presentation
What is the most common presentation?

Answer 25

the fetal part that first enters the maternal pelvis

Cephalic vertex presentation is the most common and is considered the safest

Other presentations include breech, shoulder, face and brow

Question 26

Define fetal position

Answer 26

the position of the fetal head as it exits the birth canal.
Usually the fetal head engages in the occipito-anterior position (the fetal occiput facing anteriorly) – this is ideal for birth

Question 27

Define polyhydramnios

Answer 27

the presence of amniotic fluid >95th centile

Question 28

What can cause polyhydramnios?

Answer 28

Usually idiopathic

Macrosomia – larger babies produce more urine

Maternal diabetes – especially if poorly controlled

Maternal ingestion of lithium – leads to fetal diabetes insipidus

Any condition that prevents the fetus from swallowing – e.g. oesophageal atresia, muscular dystrophies, congenital diaphragmatic hernia

Duodenal atresia – ‘double bubble’ sign on ultrasound scan

Anaemia

Fetal hydrops

Genetic or chromosomal abnormalities

Question 29

What groups can secondary causes of headaches in pregnancy be split into?

Answer 29

Hypertensive
Vascular
SOL

Question 30

What can cause hypertensive headaches in pregnancy?

Answer 30

Pre-eclampsia and eclampsia:
worsening bilateral pulsatile headache, pain can be worse with exercise and doesn’t improve with mild analgesics, visual disturbance may be present, along with other signs of end organ damage or seizures

Posterior reversible encephalopathy syndrome:
progressive headache, reduced consciousness, visual disturbance, seizures, vomiting and focal neurology

Question 31

Vascular causes of headaches in pregnancy?

Answer 31

Ischaemic stroke

Subarachnoid haemorrhage
- risk of SAH is around 20 times higher in the postnatal period compared to the general population

Cerebral venous sinus thrombosis

Reversible cerebral vasoconstriction syndrome
- recurrent, sudden, severe headache starting in the first week postnatally

Question 32

Management of primary headaches in pregnancy?

Answer 32

Conservative – minimise triggers, physical activity, regular sleeping patterns, healthy diet, acupuncture, yoga

Analgesia – paracetamol is the safest option in pregnancy, with codeine and tramadol as second-line options

Prophylaxis – propranolol is first-line for migraine prevention with amitriptyline as an alternative

Question 33

How long should LMWH be given for in women with confirmed VTE in pregnancy?

Answer 33

anticoagulation should be maintained throughout the pregnancy, until 6-12 weeks post-partum. Women should be advised to omit their dose 24 hours before any planned induction of labour or caesarean section

Question 34

What are the pros and cons of VBAC (vaginal birth after C section) versus elective repeat C section?

Answer 34

VBAC has a shorter hospital stay and recovery
1 in 200 women experience scar rupture

Question 35

How should a VBAC be managed?

Answer 35

hospital setting with facilities for emergency caesarean
Continuous CTG monitoring.
beware that additional analgesic requirements during the labour may indicate impeding uterine rupture
Avoid induction where possible
Be cautious with augmentation (increased risk of uterine scar rupture)
After 39 weeks an elective repeat caesarean is recommended delivery method.

Question 36

Contraindications to VBAC?

Answer 36

Absolute – classical caesarean scar, previous uterine rupture and any other contraindications for vaginal birth that apply to the clinical scenario (for example placenta praevia)

Relative – complex uterine scars or >2 prior lower segment Caesarean sections

Question 37

Clinical features of shoulder dystocia?

Answer 37

Difficulty in delivery of the fetal head or chin

Failure of restitution – the fetal head remains in the occipital-anterior position after delivery by extension and therefore does not ‘turn to look to the side’

‘Turtle Neck‘ sign – the fetal head retracts slightly back into the pelvis, so that the neck is no longer visible, akin to a turtle retreated into its shell

Question 38

What are the key points of postpartum contraception to remember?

Answer 38

Women become fertile 21 days after delivery

Progesterone-only methods and the copper coil are all safe immediately after delivery and during breastfeeding

Women who are not breastfeeding should wait 3 weeks to start combined hormonal contraception, those who are breastfeeding should wait 6 weeks

Contraception is needed from 5 days of ectopic pregnancy management, miscarriage or abortion

Question 39

What is a Bartholin’s cyst?

Answer 39

a fluid-filled sac within one of the Bartholin’s glands of the vagina

the Bartholin’s glands are located deep to the posterior aspect of the labia majora (at 4 and 8 o’clock) and secrete mucus to lubricate the vagina

cysts can can cause vulvar pain (particularly when walking and sitting), and superficial dyspareunia

Question 40

How are Bartholin’s cysts managed?

Answer 40

Word Catheter or marsupialisation

Question 41

What is Lichen Sclerosus?

Answer 41

chronic inflammatory skin disease of the anogenital region in women

presents with white atrophic patches on the skin, itching

bimodal incidence, peaking in prepubescent girls and post-menopausal women

can progress to squamous cell carcinoma

Question 42

How should Lichen Sclerosus be managed?

Answer 42

immunosuppression

topical steroids, such as clobetasol propionate

Question 43

Give some tubal causes of infertility in women

Answer 43

Pelvic inflammatory disease (PID)
Endometriosis
Previous sterilisation

Question 44

Give some uterine and peritoneal causes of infertility in women?

Answer 44

Endometriosis
Previous pelvic surgery (formation of adhesions, including intrauterine)
Uterine fibroids
Uterine anomalies
Cervical factors

Question 45

Investigations for a woman struggling with infertility?

Answer 45

Mid-luteal phase progesterone – to assess ovulation
Chlamydia screening
Testing for susceptibility to rubella
Serum progesterone in women with prolonged irregular menstrual cycles
Gonadotrophins in women with irregular menstrual cycles
Thyroid function tests if the symptoms are suggestive

Question 46

What tubal patency tests are available?

Answer 46

if no comorbid conditions:
Hysterosalpingography – screens for tubal occlusion

If comorbid conditions (including pelvic inflammatory disease and endometriosis):
Diagnostic laparoscopy and dye

Question 47

How do CMV infections present in pregnancy?

Answer 47

usually asymptomatic in immunocompetent individuals.

can occasionally produce a mild flu-like illness.

in some patients, it can cause a mononucleosis syndrome (similar to Epstein-Barr); resulting in fever, splenomegaly and impaired liver function.

Question 48

How can CMV in pregnancy be investigated and managed?

Answer 48

viral serology for CMV specific IgM and IgG is performed

Mx:
referred to a fetal medicine specialist
Fetal CMV infection can be diagnosed prenatally via amniocentesis and PCR
If fetal CMV infection is confirmed, there is no effective therapy, and termination of pregnancy can be offered. If the woman wishes to continue the pregnancy, serial ultrasound scanning should be performed to assess for manifestations of congenital CMV.

Question 49

Neonates born following an intrauterine CMV infection can have several problems:

Answer 49

Intrauterine growth restriction
Hepatosplenomegaly
Thrombocytopaenic purpura
Jaundice
Microencephaly
Chorioretinitis

Question 50

How can parvovirus B19 be investigated and managed in pregnancy?

Answer 50

Ix: viral serology can be performed:
Parvovirus specific IgM = recent infection
Parvovirus specific IgG = past infection and therefore immunity

The main risk of fetal parvovirus infection is fetal hydrops – the abnormal accumulation of fluid in two or more fetal compartments.

Mx is typically:
Serial ultrasound scans and Doppler assessment
Starting 4 weeks post infection or at 16 weeks.
Repeated every 1-2 weeks, until 30 weeks gestation.
If there is evidence of fetal hydrops on ultrasound, the patient should be referred to tertiary centre for intrauterine erythrocyte transfusion.

Question 51

How should rubella be investigated in pregnancy?

Answer 51

In women where rubella infection is suspected, ELISA can be performed to measure rubella specific IgG and IgM:

IgM antibody – present in acute infection.
IgG antibody – present following infection or vaccination.

Question 52

Congenital rubella syndrome describes the neonatal manifestation of infection with the rubella virus during pregnancy. What features may be present at birth?

Answer 52

Sensorineural deafness

Cardiac Defects:
Pulmonary Stenosis, Patent Ductus Arteriosus, Ventricular Septal Defect

Ophthalmic Defects:
Retinopathy, Congenital Cataracts

Central Nervous System Abnormalities:
Learning disabilities, Microencephaly

Question 53

What are the late onset features of congenital rubella syndrome?

Answer 53

Diabetes mellitus
Thyroiditis
Growth Hormone Abnormalities
Behavioural Disorders