Obs 5 Flashcards
What are the RFs for a multiple pregnancy?
- Advanced maternal age
- IVF
- Previous multiple pregnancy
Define chorion and amnion
Chorion = number of placentae
Amnion = number of amniotic sacs
Describe monozygous twins
Division of fertilised egg = IDENTICAL (20% of twins)
Dichorionic diamniotic:
- Cleavage days 1-3
- 2 placenta and 2 amniotic sacs
- S/S: λ sign
Monochorionic diamniotic:
- Cleavage days 4-8
- 1 placenta (share), 2 amniotic sacs
- S/S: T-sign
Monochorionic monoamniotic:
- Cleavage days 8-12
- 1 placenta (share), 1 amniotic sac (share)
- S/S: T-sign, ‘entangled cords’
Conjoined twins:
- Cleavage days 13-15
Describe dizygous twins
Fertilisation of 2 ovum by 2 different sperm = NON-IDENTICAL (80% of twins)
- DCDA – separate placentae, amnions, chorions
How is GA estimated for multiple pregnancies?
Offer 1st trimester USS when CRL 45-84 mm (11-13+6 weeks) to determine: EGA, chorionicity, and to screen for Down syndrome (use largest baby to estimate GA)
How is chronionicity detected for multiple pregnancies?
> Refers to the type of placentation (this is the most important feature to an obstetrician)
- Detect at time of detecting twin/triplet pregnancy by USS using number of placental masses, lambda (dichorionic) or T-sign (monochorionic) and membrane thickness
- Examine junction between the inter-fetal membrane and the placenta
- In DC pregnancies = triangular placental tissue projection (λ sign) into base of the membrane
- In MC pregnancies = no placental tissue projection (T-sign) into the base of the membrane
- If presenting after 14 weeks, determine chorionicity using all of membrane thickness, lambda sign, number of placental masses and disconcordant foetal sex
What are the S/S of multiple pregnancies?
(Asymptomatic):
1st trimester = incidental on USS, hyperemesis (increased βHCG)
2nd trimester = large for dates, multiple parts on abdominal exam
Abdominal exam = increased SFH, multiple parts, >1 FH
What is the antenatal management of a multiple pregnancy?
- FBC at 20-24w (query extra supplementation of iron or folic acid, repeat at 28w)
- BP (increased chance of eclampsia)
- GTT (increased likelihood of diabetes) - 16w (every 2w) for MC, 20w (every 4w) for DC
- TTTS screening = every 2 weeks from 16-24 weeks – if MC
- General growth scans = after 24w (every 2 or 4 weeks)
Serial USS for foetal growths:
- MC twins = scan at 12, 16 and then every 2 weeks until delivery
- DC twins = scan at 12, 20 and then every 4 weeks until delivery
- MC/ DC triplets = scan at 12, 16 and every 2 weeks until delivery
- TC triplets = scan at 12, 20 and every 4 weeks until delivery
Describe the specialist care for multiple pregnancies
- Uncomplicated monochorionic diamniotic twin pregnancy should be offered at least 9 appointments with a healthcare professional, at least 2 should be with a specialist obstetrician
- Uncomplicated dichorionic twin pregnancy should be offered at least 8 appointments and at least 2 with a specialist obstetrician
- Uncomplicated monochorionic triamniotic or dichorionic triamniotic pregnancy should be offered at least 11 appointments and at least 2 with a specialist obstetrician
- Uncomplicated trichorionic triamniotic triplet pregnancy should be offered at least 7 scans and at least 2 with a specialist obstetrician
How is pre-term birth in multiple pregnancies prevented?
Do NOT use the following routinely to prevent spontaneous preterm birth:
- Bed rest at home or in hospital
- IM or vaginal progesterone
- Cervical cerclage
- Oral tocolytics
- Corticosteroids will be useful if preterm birth is likely (should be targeted)
Describe the birth of multiple pregnancies
- 60% of twin pregnancies result in spontaneous birth before 37 weeks
- Offer continuous foetal monitoring (CTG); if needed: scalp electrode and foetal blood monitoring
- Offer elective birth if (if declined > weekly obstetrician appointments):
- Uncomplicated monochorionic twin – from 36 weeks (after course of steroids)
- Uncomplicated dichorionic twin – from 37 weeks
- Uncomplicated triplet – from 35 weeks (after a course of steroids)
Vaginal delivery (first twin is in the cephalic position; 2nd may be breech but this is ok)
- Second breech baby can be turned using Internal Pedalic Version (IPV)
Describe the foetal complications of multiple pregnancies
IUGR:
(and discordant IUGR: when one baby is SGA and the other normal or LGA)
- Monitored with EFW discordance (not SFH)
- Difference in size >20% is an indicator of IUGR
Intra-uterine death (IUD):
- For dizygotic twins, the other twin will be fine
- In monochorionic, this can be bad as the BP will drop in the surviving twins’ placenta > neurological damage in the surviving twin in 25%
Down Syndrome:
(greater absolute risk as same risk PER baby so increased TOTAL risk)
Also:
- Structural Abnormalities (2x in monozygotic babies)
- Twin-to-Twin Transfusion Syndrome (TTTS)
- Malpresentation
- Premature
What are the maternal complications of multiple pregnancies?
- Pre-eclampsia (more risk of abnormal vasculature development)
- Hyperemesis gravidarum (more bHCG)
- GDM (more placental lactogen and placental steroids so more likely to tip into diabetes)
- APH, PPH (stretched uterus)
- Anaemia and thrombocytopaenia (more required to sustain the two children)
What is TTTS?
Results from an unbalanced blood supply through placental anastomoses in monochorionic twins
Donor twin = growth restriction, renal tubular dysgenesis, and oliguria
Recipient twin = visceromegaly and polyuria
Mother = sudden abdomen size increase, SOB
- Start diagnostic monitoring with USS from 16-24 weeks on a 2-weekly basis
- Delivered by 34-37 weeks
- New treatment (<26w) = foetoscopic laser ablation of vascular anastomoses
- New treatment (>26w) = delivery
What are RFs for high-risk pregnancies?
- Any previous complicated pregnancies (biggest risk for another abnormal pregnancy)
- Age <15yo or >35yo
- Pre-pregnancy weight under 45kg or obese
- Height under 5 ft (1.5m)
- Incompetent cervix
- Uterine malformations
- Small pelvis
- Being single, smoker, alcohol, illicit drugs
- No access to early prenatal care
- Low socioeconomic status
- Hx of recurrent miscarriages
- Hypothyroid / Hyperthyroid
What is the management of high-risk pregnancies?
- Continued surveillance for high risk patients – more frequent scans
- Offer high dose folate 5mg – also given to…
- Previous child with NTD
- Diabetes mellitus
- Woman on an anti-epileptic
- Obesity
- HIV positive taking co-trimoxazole
- Sickle cell disease
- Offer low dose aspirin (75mg, OD) as prophylaxis for pre-eclampsia
Define obesity in pregnancy
Obesity = BMI >30kg/m2
What is the aetiology of obesity in pregnancy?
Pre-existing obesity – poor diet, lack of exercise
Fluid retention – polyhydramnios, heart, kidney, liver failure
What are the S/S of obesity in pregnancy?
Obesity
+Associated conditions may be present:
- GDM
- Pre-eclampsia
- Infections
What are the investigations for obesity in pregnancy?
- BMI monitoring
- Bloods – FBC, LFT, UE, cholesterol, OGTT
- USS – liquor volume, foetal growth scans
What is the management of obesity in pregnancy?
Conservative:
- More exercise, better diet, vitamin D supplementation
Labour planning:
- Assess risk of giving birth via vaginal delivery and whether there needs to be induction/CS
Post-natal follow up:
- T2DM testing
What are the complications of obesity in pregnancy?
- GDM
- Pre-eclampsia
- Infections
- Overdue pregnancy, labour difficulties, CS or miscarriage
Prognosis – almost 1/3 maternal deaths are in obese mothers
What is oligohydramnios?
Decreased volume of amniotic fluid, <5th centile, deepest pool <2cm
What are the causes of oligohydramnios?
Reduced input fluid:
- Placental insufficiency
- Pre-eclampsia
Reduced output fluid:
- Structural pathology (renal agenesis, atresia of ureter / urethra)
- Medications (ACEi, NSAIDs)
Lost fluid:
- Amniotic rupture
What are the S/S of oligohydramnios?
Commonly asymptomatic
- History of fluid leak PV, rupture of membranes
- Abdominal exam – decreased fundal height, foetal parts easily palpable
- Speculum – assess for membrane rupture if appropriate
What are the investigations for oligohydramnios?
- Speculum - assess for membrane rupture
- USS – liquor volume, foetal anomalies
- CTG– foetal wellbeing
What is the management of oligohydramnios?
Planned birth in an obstetric unit is recommended
Pre-Term:
- Expectant management
- Ongoing antepartum surveillance
- Continuous fetal heart rate monitoring during labour
- Delivery if further abnormalities arise
Term:
- Delivery is often the most appropriate management
What are the complications of olighydramnios?
Labour:
- Increased incidence of CTG abnormalities
- Meconium liquor
- Emergency CS
Neonate: can cause POTTER SEQUENCE
- Pulmonary hypoplasia
- Twisted faces
- Twisted skin
- Extremity deformities
- Renal agenesis
Prognosis – increased perinatal mortality rates with early onset oligohydramnios
What is polyhydramnios?
Increased volume of amniotic fluid, above 95th centile, or deepest pool greater than 8 cm.
What are the causes of polyhydramnios?
Failure of foetal swallowing:
- Neurological / chromosomal abnormalities
- GIT (duodenal atresia, oesophageal atresia, TOF)
Foetal polyuria:
- Maternal diabetes
- TTTS
Also:
- Congenital infections
What are the S/S of polyhydramnios?
- Symptoms of underlying cause
- Abdomen – increased fundal height, impalpable foetal parts, tense abdo
What are the investigations for polyhydramnios?
- USS - liquor volume, foetal growth
- Umbilical artery dopplers - exclude foetal anomalies
- Other – exclude maternal diabetes
What is the management of polyhydramnios?
- Antenatal monitoring of foetus, ensure diabetes control, paediatrician present at delivery
- Amnioreduction (if gross polyhydramnios / discomfort)
- COX inhibitors to decrease foetal urine output
What are the complications of polyhydramnios?
- PTL
- Malpresentation
- Placental abruption
- Cord prolapse
- PPH
- Increased risk CS
Prognosis – increased perinatal morbidity and mortality, related to PTL/congenital
Define a low-lying placenta
Placental edge is <2cm from internal os on TVUSS
What is placenta praevia?
Placenta lies over the internal os (diagnosed at ≥32 weeks)
What are the types of placenta praevia?
Classical grading:
- I = placenta does not cover internal cervical os but is low lying
- II = placenta reaches internal os but doesn’t cover it (lower edge reaching internal os)
- III = placenta covers the internal os before dilation but not when dilated / lower edge partially covering the internal os
- IV (‘major’) = placenta completely covers the internal os
What are the RFs for placenta praevia?
- Multiple pregnancy
- Increased maternal age
- Previous uterine surgery (i.e. CS)
- Previous praevia history
- Smoking
- IVF (6x increased risk)
What are the S/S of placenta praevia?
- Painless bright red PV bleeding in 2nd or 3rd trimester
- Can have small bleeds before large
- Potential signs of shock (shock in proportion to visible loss)
- Uterus not tender
- Lie and presentation may be abnormal
- Fetal heart usually normal
- Coagulation problems rare
What are the investigations for placenta praevia?
Digital vaginal examination should not be performed before an USS as it may provoke a severe haemorrhage (speculum ok to assess bleeding)
- 1st line diagnosis: TVUSS
- Bloods – FBC, clotting studies, G&S, U&E, LFT
- If mother RhD -ve: Kleihauer test (check level of foetal blood in maternal circulation) +/- administer anti-D
- CTG
Placenta praevia often picked up on routine 20w abdominal USS
What is the management of placenta praevia?
1. Picked up on 20w anomaly scan:
- Only 10% go on to have a low-lying placenta later in pregnancy
- Rescan at 32 weeks
2. USS at 32 weeks:
- Still present and grade I/II: Rescan at 36 weeks
- Still present and grade III/IV: Admit at 34 weeks with CS at 37 weeks
3. USS at 36 weeks:
- Grade I = vaginal delivery
- Grade III/IV = CS
Also:
- Antenatal corticosteroids from 34-36 weeks (can be earlier if at risk of PTL)
- Tocolysis (facilitate antenatal corticosteroids)
- General advice: NOT to have sex if low-lying placenta or placenta praevia
If a woman with known placenta praevia goes into labour prior to the elective C section, an emergency C section should be performed due to the risk of PPH
What is the management of placenta praevia with bleeding?
- Admit and ABC approach (IV access and fluids)
- Bloods: FBC, G&S, consider crossmatch, Kleihauer test
- Anti-D if Rh-D -ve and Kleihauer test
- Admit at least until bleeding has stopped (and keep them in for 48 hours to observe)
- If not able to stabilise = emergency C section
- If in labour or term reached = emergency C section
Scans:
- CTG (if >27 weeks)
- Umbilical artery dopplers (every 2 weeks)
- Growth scan
What are the complications of placenta praevia?
Maternal:
- Haemorrhage – antepartum and postpartum
- DIC
- Hysterectomy
- Maternal mortality is 1 in 300
Foetal:
- IUGR
- Death
What is vasa praevia?
Foetal blood vessels connecting the umbilical cord to the placenta travel across the internal cervical os and below the foetal presenting part, unprotected by placental tissue or umbilical cord
> When baby descends, they can rupture the vessels
What are the 2 types of vasa praevia?
Type 1 VP = vessels connect a velamentous umbilical cord to the placenta (single or bilobed placenta)
Type 2 VP = vessels connect the lobes of the placenta (single or bilobed) to 1 or more succenturiate lobes (accessory lobes)
What is Benckaiser’s haemorrhage?
The haemorrhage of blood when the vessels are ruptured
What are the RFs for vasa praevia?
- Foetal anomaly (bilobed placenta or succenturiate lobes)
- History of low-lying placenta in 2nd trimester
- Multiple pregnancies
- IVF
What are the S/S of vasa praevia?
Typical picture = ROM > fresh PV bleeding + foetal bradycardia
- After the membranes rupture, the veins alone can’t hold the weight of the baby > bleeding
- Foetal HR abnormalities – decelerations, bradycardia, sinusoidal trace, foetal demise
- O/E > you can palpate the vessels in the membranes, amnioscope can directly visualise this
What are the investigations for vasa praevia?
Can be clinical based on sx
- Usually diagnosed via TVUSS with Doppler
- VE - may be able to detect pulsating foetal vessels inside internal os
- Kleihauer test (measures amount of foetal Hb in a mother’s bloodstream)
- Haemoglobin electrophoresis – identify if foetal or maternal blood (takes a long time)
- Doppler USS
What is the management of vasa praevia?
C-section
> Rapid delivery + aggressive resuscitation including use of blood transfusion if required are essential
What are the complications of vasa praevia?
Foetal mortality if presenting with haemorrhage is 60% but if identified antenatally its 3%
- No major maternal risk
- Foetus: Loss of relatively small amounts of blood can have major implications for the foetus
What is placental abruption?
Separation of the placenta from the uterine wall before delivery (>24 weeks; if <24w, miscarriage)
Haemorrhage may be concealed (20%) or revealed (80%)
What are the RFs for placental abruption?
- Previous placental abruption
- HTN
- Previous APH
- PPROM
- Abdominal trauma
- Smoking, cocaine
- Polyhydramnios
- Idiopathic
Although most cases occur in low-risk pregnancies
What are the S/S of placental abruption?
Constant abdominal pain ± PV bleeding (if revealed – 80%), SUSTAINED contractions
On examination:
- General – shock out of keeping with visible loss
- Abdomen – hypertonic “woody” tender uterus
- Speculum – assess bleeding
- Vaginal exam (NOT in praevia) – cervical dilatation
- Normal lie and presentation
- Fetal heart: absent/distressed
- Coagulation problems
- Beware pre-eclampsia, DIC, anuria
What is a key difference between placenta praevia and placental abruption?
Praevia = bleed, no pain
Abruption = bleed, pain
What are the investigations for placental abruption?
- Basic obs
- Abdominal exam
- Bloods – FBC, clotting, U&E, crossmatch
- CTG for baby
- TVUSS – exclude praevia – abruption unlikely to be present unless very large, may show retroplacental collection of blood
If unsure if praevia, DO NOT BIMANUAL
What is the management of placental abruption?
Mild:
- If preterm and stable: conservative management with close monitoring > IOL at term
- Admit for at least 48 hours or until bleeding stops
- Anti-D Ig followed by Kleihauer test
- Foetus alive and >36 weeks without distress = vaginal delivery
Severe:
- ABC > 2x wide bore cannulae, fluids, blood transfusions, correct coagulopathies
- Foetus alive and >36 weeks and distress = Emergency CS
- Corticosteroids for foetal lung development (between 24-34+6w)
- Consider IOL if foetal compromise
- Foetus dead = induce vaginal delivery
What are the complications of placental abruption?
Maternal:
- Haemorrhage (APH, PPH)
- DIC
- Renal failure
- “Couvelaire uterus” (extravasation of blood into myometrium and beneath the peritoneum > very hard uterus)
- Sheehan syndrome
Foetal:
- Birth asphyxia
- Death
What antenatal Down Syndrome screening is offered?
Combined test is now standard:
- Should be done between 11 - 13+6 weeks
- High HCG, low pregnancy-associated plasma protein A (PAPP-A), thickened nuchal translucency
Quadruple test:
- If women book later in pregnancy the quadruple test should be offered between 15 - 20 weeks
- Low Alpha-fetoprotein, low unconjugated oestriol, high HCG and high inhibin A
