Fetal Medicine Flashcards
Echogenic bowel
Causes, investigations, management
1% in second trimester
Causes:
* Cystic fibrosis
* CMV, toxoplasmosis
* Trisomy 21
* Congenital bowel anomaly - atresia, obstruction, perforation, Hirschprung’s
* IUGR - mesenteric ischaemia
* Swallowed blood
* Alpha thalassaemia
* Fetal alcohol syndrome
* Normal, no concern - 75% cases
Investigations:
* NIPT
* Invasive test - CVS or amnio
* USS detailed anatomy and growth - other markers of aneuploidy
* Maternal CMV/Toxo IgG and IgM
* CMV/Toxo PCR if amnio
* Parental CF screen, otherwise test on amnio
* Parental thalassaemia screen - FBC (HB, MCV), Fe, electrophoresis, genetic screen
Management:
* Above
* Paeds consult
* 4weekly follow up
* Paeds at birth
A CVS performed for increased risk MSS1 reveals a balanced translocation. How do you proceed?
Counsel, further management
Counsel - switching of sections of DNA, all material is still there in correct number - no loss or gain.
Impact uncertain - may be significant, minor or not at all. Will depend if breakage is at point of a gene and whether it is important.
Future childbearing may be affected as gametes pass on same changes. May be healthy but could also cause congenital abnormalities or miscarriage
Screen karyotypes of both parents
Genetics referral
Options - TOP, continue
Growth USS, detailed anatomy
What are causes for fetal hydrops and how do you investiagte?
Causes:
Immune
* Rh disease
* Other antibodies (Kell in particular)
Non-immune
* Infection - parvovirus, CMV, syhpilis
* Fetal anaemia - haemolytic, volume loss, thalassaemia
* Metabolic - G6PD
* Cardiac defect - congenital, heart block
* TTTS
* Mirror syndrome
* Aneuploidy e.g. Turner’s
Chromosomal
Anaemia
Unexplained
Structural
Twins
Infection
Cardiac
Investigations:
* MCA PSV
* Antibody screen
* Serology - parvovirus, syphilis, CMV, toxoplasmosis
* FBC, MCV, Fe - thalassaemia screen of parents if low MCV (DNA analysis for alpha)
* Kleihauer
* Detailed structural assessment
* Fetal echo
* Anti Ro/La if heartblock
* Amniocentesis - karyotype, infection, thalassaemia
Manage:
* Assess above
* Poor prognosis 50-90% mortality
* Consider need for delivery
You are referred a woman who is G4P1 who is Anti-K (Kell antibody) positive with a titre of 1:128.
Outline your assessment, investigations and management plan for this woman.
- History - transfusions, prev pregnancy outcomes, HDFN, jaundice
- Counsel re risks - HDFN from transplacental antibody passage as attaches to bone marrow precursors (anaemia, hydrops, death, PTB)
- Test partner’s Kell genotype (if paternity certain)
if Kell negative: no further action
if Kell heterozygous: cfDNA test or amniocentesis for fetal genotype
if Kell homozygous: refer MFM - Weekly MCA PSV, assess for hydrops from 16weeks
- If PSV >1.5 MoM: Cordocentesis to check Hb +/- RBC transfusion
- Titres 4weekly until 28 weeks then 2weekly
- IOL 37weeks (if IUTs often don’t do past 34weeks as risks higher than risk of prematurity)
- At delivery ensure neonatal team aware with RBCs available and ensure at least 2units crossmatched (4 if higher risk) for mother
- Postnatal - cord bloods for DAT, Hb, Bili
How do you explain to a patient kell antibodies?
She has antibodies towards a red blood cell antigen called Kell. Likley originate from a previous blood transfusion or from a FMH in previous pregnancy.
These antibodies can cross the placenta to baby. If baby is Kell-positive they can develop significant anaemia and heart failure secondary to antibody destruction of cells that make red blood cells. Titres do not correlate with extent of disease.
Umbilical vein varix
Assess:
*
Counsel:
* Dilation of umbilical vein intra-abdominal
* Associated genetic abnormalities 10%, structural abnormalities 20%
* Risk of thrombosis in varix
* 4% stillbirth prelabour in late third trimester
Manage:
* MFM referral
* Detailed anatomy USS
* Consider invasive testing
* Weekly USS
* Once to twice weekly CTGs from 32weeks
* IOL 39+ weeeks
* CTG in labour
Fetal arrthymia
Tachycardia:
Assess - TRABs
Detailed cardiac scan
Treat
Bradycardia:
Causes - Congenital heart block, structural, long QT syndrome
Assess - Anti-Ro/La antibodies, detailed cardiac scan and screen for hydrops
Manage -
Fetal ventriculomegaly
Definitions:
Causes:
* Congenital infection
* Neural tube defect
* Structural abnormalities
* IVH
* Aneuploidy
Assess:
* Maternal serology
* Tertiary anatomy USS
* Antiplatelet antibodies
* Maternal platelet specific antibodies
Counsel:
* Prognosis depends on severity and association with abnormalities
* Small neurodevelopmental delay with mild, isolated
Manage:
FNAIT
Assess:
Counsel:
Manage:
According to gestation of
* IVIG from 16weeks, give at 12 weeks if severely affected sibling
* IVIG from 20weeks if no sibling affected
* Serial USS 2-4weeks to assess fetal brain and for ICH
* Delivery - consider ElCS if prev baby affected, otherwise
* PN - regular neonatal plt surveillance as nadir usually 4days, neonatal head USS
Gastroschisis
Abdominal wall defect
Assess:
* Detailed anatomy scan
* Extent of bowel involvement
Counsel:
* Good prognosis if isolated
* Survival - 90%, IUFD 10%
* Risk of IUGR
* Complications arise from bowel dilation, obstruction, IUGR
Manage:
* Serial growth USS
* IOL 37-38weeks
* Aim vaginal delivery
* Don’t feed at birth, wrap abdomen in gladwrap
*
Increased NT
> 95% for gestation or >99% if 3.5mm
Measure if CRL <84mm
Causes:
* Chromosomal abnormalities
* Cardiac defects
Counsel:
* Prognosis worsens with increasing size and associated chromosomal abnormality
Manage:
* Detailed anatomy USS
* Amniocentesis
Ebstein’s anomaly
Tricuspid valve defectm increased R atrial pressure, patent FO, cyanosis
Causes:
* Lithium
* Valproate
* SSRI
Management
* MFM
* Surgical repair
*
Talipes
1:1000
More common in male fetus, Fhx, Maori ethnicity
Indrawing of the fetal feet, diagnosed on USS when feet are seen in the same plane as tibia/fibula
Congenital pulmonary airway malformation
Complications:
Survival >95%
No increased risk of recurrence
Low association with chromosomal conditions
Omphalocoele
Midline defect, contains abdominal contents contained within sac, at the base of the umbilicus. Develops after failure of the midgut to return to abdomen after first trimester.
Assess:
* Extent of involvement
* Detailed anatomy
* Amniocentesis
Counsel:
* Strong association with chromosomal abnormality >50%
* Risk IUGR, stillbirth
*
Manage:
* MFM referral
* Psychological support, written information
* MDT review - paeds surg
* Consider TOP
* Growth surveillance
* Aim vaginal birth but CS if large amount of liver involvement
* Do not feed, cover with wrapping
* Postnatal repair
